patch, 5 partsFilter combination

list-objects-filter.c, list-objects-filter.h, list-objects.c

diff --git a/list-objects-filter.c b/list-objects-filter.c
index ee449de3f7..8e8616b9b8 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -19,82 +19,60 @@
  * FILTER_SHOWN_BUT_REVISIT -- we set this bit on tree objects
  * that have been shown, but should be revisited if they appear
  * in the traversal (until we mark it SEEN).  This is a way to
  * let us silently de-dup calls to show() in the caller.  This
  * is subtly different from the "revision.h:SHOWN" and the
  * "sha1-name.c:ONELINE_SEEN" bits.  And also different from
  * the non-de-dup usage in pack-bitmap.c
  */
 #define FILTER_SHOWN_BUT_REVISIT (1<<21)
 
-/*
- * A filter for list-objects to omit ALL blobs from the traversal.
- * And to OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_blobs_none_data {
-	struct oidset *omits;
-};
-
 static enum list_objects_filter_result filter_blobs_none(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_context *ctx)
 {
-	struct filter_blobs_none_data *filter_data = filter_data_;
-
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		/* always include all tree objects */
 		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 
 	case LOFS_END_TREE:
 		assert(obj->type == OBJ_TREE);
 		return LOFR_ZERO;
 
 	case LOFS_BLOB:
 		assert(obj->type == OBJ_BLOB);
 		assert((obj->flags & SEEN) == 0);
 
-		if (filter_data->omits)
-			oidset_insert(filter_data->omits, &obj->oid);
+		if (ctx->omits)
+			oidset_insert(ctx->omits, &obj->oid);
 		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
 	}
 }
 
-static void *filter_blobs_none__init(
-	struct oidset *omitted,
+static void filter_blobs_none__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_context *ctx)
 {
-	struct filter_blobs_none_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
-
-	*filter_fn = filter_blobs_none;
-	*filter_free_fn = free;
-	return d;
+	ctx->filter_fn = filter_blobs_none;
 }
 
-/*
- * A filter for list-objects to omit ALL trees and blobs from the traversal.
- * Can OPTIONALLY collect a list of the omitted OIDs.
- */
+/* A filter for list-objects to omit ALL trees and blobs from the traversal. */
 struct filter_trees_depth_data {
-	struct oidset *omits;
-
 	/*
 	 * Maps trees to the minimum depth at which they were seen. It is not
 	 * necessary to re-traverse a tree at deeper or equal depths than it has
 	 * already been traversed.
 	 *
 	 * We can't use LOFR_MARK_SEEN for tree objects since this will prevent
 	 * it from being traversed at shallower depths.
 	 */
 	struct oidmap seen_at_depth;
 
@@ -103,41 +81,41 @@ struct filter_trees_depth_data {
 };
 
 struct seen_map_entry {
 	struct oidmap_entry base;
 	size_t depth;
 };
 
 /* Returns 1 if the oid was in the omits set before it was invoked. */
 static int filter_trees_update_omits(
 	struct object *obj,
-	struct filter_trees_depth_data *filter_data,
+	struct filter_context *ctx,
 	int include_it)
 {
-	if (!filter_data->omits)
+	if (!ctx->omits)
 		return 0;
 
 	if (include_it)
-		return oidset_remove(filter_data->omits, &obj->oid);
+		return oidset_remove(ctx->omits, &obj->oid);
 	else
-		return oidset_insert(filter_data->omits, &obj->oid);
+		return oidset_insert(ctx->omits, &obj->oid);
 }
 
 static enum list_objects_filter_result filter_trees_depth(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_context *ctx)
 {
-	struct filter_trees_depth_data *filter_data = filter_data_;
+	struct filter_trees_depth_data *filter_data = ctx->data;
 	struct seen_map_entry *seen_info;
 	int include_it = filter_data->current_depth <
 		filter_data->exclude_depth;
 	int filter_res;
 	int already_seen;
 
 	/*
 	 * Note that we do not use _MARK_SEEN in order to allow re-traversal in
 	 * case we encounter a tree or blob again at a shallower depth.
 	 */
@@ -145,47 +123,47 @@ static enum list_objects_filter_result filter_trees_depth(
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_END_TREE:
 		assert(obj->type == OBJ_TREE);
 		filter_data->current_depth--;
 		return LOFR_ZERO;
 
 	case LOFS_BLOB:
-		filter_trees_update_omits(obj, filter_data, include_it);
+		filter_trees_update_omits(obj, ctx, include_it);
 		return include_it ? LOFR_MARK_SEEN | LOFR_DO_SHOW : LOFR_ZERO;
 
 	case LOFS_BEGIN_TREE:
 		seen_info = oidmap_get(
 			&filter_data->seen_at_depth, &obj->oid);
 		if (!seen_info) {
 			seen_info = xcalloc(1, sizeof(*seen_info));
 			oidcpy(&seen_info->base.oid, &obj->oid);
 			seen_info->depth = filter_data->current_depth;
 			oidmap_put(&filter_data->seen_at_depth, seen_info);
 			already_seen = 0;
 		} else {
 			already_seen =
 				filter_data->current_depth >= seen_info->depth;
 		}
 
 		if (already_seen) {
 			filter_res = LOFR_SKIP_TREE;
 		} else {
 			int been_omitted = filter_trees_update_omits(
-				obj, filter_data, include_it);
+				obj, ctx, include_it);
 			seen_info->depth = filter_data->current_depth;
 
 			if (include_it)
 				filter_res = LOFR_DO_SHOW;
-			else if (filter_data->omits && !been_omitted)
+			else if (ctx->omits && !been_omitted)
 				/*
 				 * Must update omit information of children
 				 * recursively; they have not been omitted yet.
 				 */
 				filter_res = LOFR_ZERO;
 			else
 				filter_res = LOFR_SKIP_TREE;
 		}
 
 		filter_data->current_depth++;
@@ -194,55 +172,48 @@ static enum list_objects_filter_result filter_trees_depth(
 }
 
 static void filter_trees_free(void *filter_data) {
 	struct filter_trees_depth_data *d = filter_data;
 	if (!d)
 		return;
 	oidmap_free(&d->seen_at_depth, 1);
 	free(d);
 }
 
-static void *filter_trees_depth__init(
-	struct oidset *omitted,
+static void filter_trees_depth__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_context *ctx)
 {
 	struct filter_trees_depth_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	oidmap_init(&d->seen_at_depth, 0);
 	d->exclude_depth = filter_options->tree_exclude_depth;
 	d->current_depth = 0;
 
-	*filter_fn = filter_trees_depth;
-	*filter_free_fn = filter_trees_free;
-	return d;
+	ctx->filter_fn = filter_trees_depth;
+	ctx->free_fn = filter_trees_free;
+	ctx->data = d;
 }
 
-/*
- * A filter for list-objects to omit large blobs.
- * And to OPTIONALLY collect a list of the omitted OIDs.
- */
+/* A filter for list-objects to omit large blobs. */
 struct filter_blobs_limit_data {
-	struct oidset *omits;
 	unsigned long max_bytes;
 };
 
 static enum list_objects_filter_result filter_blobs_limit(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_context *ctx)
 {
-	struct filter_blobs_limit_data *filter_data = filter_data_;
+	struct filter_blobs_limit_data *filter_data = ctx->data;
 	unsigned long object_length;
 	enum object_type t;
 
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		/* always include all tree objects */
@@ -263,44 +234,41 @@ static enum list_objects_filter_result filter_blobs_limit(
 			 * apply the size filter criteria.  Be conservative
 			 * and force show it (and let the caller deal with
 			 * the ambiguity).
 			 */
 			goto include_it;
 		}
 
 		if (object_length < filter_data->max_bytes)
 			goto include_it;
 
-		if (filter_data->omits)
-			oidset_insert(filter_data->omits, &obj->oid);
+		if (ctx->omits)
+			oidset_insert(ctx->omits, &obj->oid);
 		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
 	}
 
 include_it:
-	if (filter_data->omits)
-		oidset_remove(filter_data->omits, &obj->oid);
+	if (ctx->omits)
+		oidset_remove(ctx->omits, &obj->oid);
 	return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 }
 
-static void *filter_blobs_limit__init(
-	struct oidset *omitted,
+static void filter_blobs_limit__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_context *ctx)
 {
 	struct filter_blobs_limit_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	d->max_bytes = filter_options->blob_limit_value;
 
-	*filter_fn = filter_blobs_limit;
-	*filter_free_fn = free;
-	return d;
+	ctx->filter_fn = filter_blobs_limit;
+	ctx->free_fn = free;
+	ctx->data = d;
 }
 
 /*
  * A filter driven by a sparse-checkout specification to only
  * include blobs that a sparse checkout would populate.
  *
  * The sparse-checkout spec can be loaded from a blob with the
  * given OID or from a local pathname.  We allow an OID because
  * the repo may be bare or we may be doing the filtering on the
  * server.
@@ -319,36 +287,35 @@ struct frame {
 	 * omitted objects.
 	 *
 	 * 0 if everything (recursively) contained in this directory
 	 * has been explicitly included (SHOWN) in the result and
 	 * the directory may be short-cut later in the traversal.
 	 */
 	unsigned child_prov_omit : 1;
 };
 
 struct filter_sparse_data {
-	struct oidset *omits;
 	struct exclude_list el;
 
 	size_t nr, alloc;
 	struct frame *array_frame;
 };
 
 static enum list_objects_filter_result filter_sparse(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_context *ctx)
 {
-	struct filter_sparse_data *filter_data = filter_data_;
+	struct filter_sparse_data *filter_data = ctx->data;
 	int val, dtype;
 	struct frame *frame;
 
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		dtype = DT_DIR;
@@ -414,128 +381,117 @@ static enum list_objects_filter_result filter_sparse(
 
 		frame = &filter_data->array_frame[filter_data->nr];
 
 		dtype = DT_REG;
 		val = is_excluded_from_list(pathname, strlen(pathname),
 					    filename, &dtype, &filter_data->el,
 					    r->index);
 		if (val < 0)
 			val = frame->defval;
 		if (val > 0) {
-			if (filter_data->omits)
-				oidset_remove(filter_data->omits, &obj->oid);
+			if (ctx->omits)
+				oidset_remove(ctx->omits, &obj->oid);
 			return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 		}
 
 		/*
 		 * Provisionally omit it.  We've already established that
 		 * this pathname is not in the sparse-checkout specification
 		 * with the CURRENT pathname, so we *WANT* to omit this blob.
 		 *
 		 * However, a pathname elsewhere in the tree may also
 		 * reference this same blob, so we cannot reject it yet.
 		 * Leave the LOFR_ bits unset so that if the blob appears
 		 * again in the traversal, we will be asked again.
 		 */
-		if (filter_data->omits)
-			oidset_insert(filter_data->omits, &obj->oid);
+		if (ctx->omits)
+			oidset_insert(ctx->omits, &obj->oid);
 
 		/*
 		 * Remember that at least 1 blob in this tree was
 		 * provisionally omitted.  This prevents us from short
 		 * cutting the tree in future iterations.
 		 */
 		frame->child_prov_omit = 1;
 		return LOFR_ZERO;
 	}
 }
 
 
 static void filter_sparse_free(void *filter_data)
 {
 	struct filter_sparse_data *d = filter_data;
 	/* TODO free contents of 'd' */
 	free(d);
 }
 
-static void *filter_sparse_oid__init(
-	struct oidset *omitted,
+static void filter_sparse_oid__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_context *ctx)
 {
 	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	if (add_excludes_from_blob_to_list(filter_options->sparse_oid_value,
 					   NULL, 0, &d->el) < 0)
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
-	*filter_fn = filter_sparse;
-	*filter_free_fn = filter_sparse_free;
-	return d;
+	ctx->filter_fn = filter_sparse;
+	ctx->free_fn = filter_sparse_free;
+	ctx->data = d;
 }
 
-static void *filter_sparse_path__init(
-	struct oidset *omitted,
+static void filter_sparse_path__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_context *ctx)
 {
 	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	if (add_excludes_from_file_to_list(filter_options->sparse_path_value,
 					   NULL, 0, &d->el, NULL) < 0)
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
-	*filter_fn = filter_sparse;
-	*filter_free_fn = filter_sparse_free;
-	return d;
+	ctx->filter_fn = filter_sparse;
+	ctx->free_fn = filter_sparse_free;
+	ctx->data = d;
 }
 
-typedef void *(*filter_init_fn)(
-	struct oidset *omitted,
+typedef void (*filter_init_fn)(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn);
+	struct filter_context *ctx);
 
 /*
  * Must match "enum list_objects_filter_choice".
  */
 static filter_init_fn s_filters[] = {
 	NULL,
 	filter_blobs_none__init,
 	filter_blobs_limit__init,
 	filter_trees_depth__init,
 	filter_sparse_oid__init,
 	filter_sparse_path__init,
 };
 
-void *list_objects_filter__init(
+void list_objects_filter__init(
 	struct oidset *omitted,
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_context *ctx)
 {
 	filter_init_fn init_fn;
 
 	assert((sizeof(s_filters) / sizeof(s_filters[0])) == LOFC__COUNT);
 
 	if (filter_options->choice >= LOFC__COUNT)
 		BUG("invalid list-objects filter choice: %d",
 		    filter_options->choice);
 
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->omits = omitted;
 	init_fn = s_filters[filter_options->choice];
 	if (init_fn)
-		return init_fn(omitted, filter_options,
-			       filter_fn, filter_free_fn);
-	*filter_fn = NULL;
-	*filter_free_fn = NULL;
-	return NULL;
+		init_fn(filter_options, ctx);
 }
diff --git a/list-objects-filter.h b/list-objects-filter.h
index 1d45a4ad57..ee807f5d9b 100644
--- a/list-objects-filter.h
+++ b/list-objects-filter.h
@@ -53,37 +53,46 @@ enum list_objects_filter_result {
 	LOFR_DO_SHOW   = 1<<1,
 	LOFR_SKIP_TREE = 1<<2,
 };
 
 enum list_objects_filter_situation {
 	LOFS_BEGIN_TREE,
 	LOFS_END_TREE,
 	LOFS_BLOB
 };
 
-typedef enum list_objects_filter_result (*filter_object_fn)(
-	struct repository *r,
-	enum list_objects_filter_situation filter_situation,
-	struct object *obj,
-	const char *pathname,
-	const char *filename,
-	void *filter_data);
+struct filter_context {
+	enum list_objects_filter_result (*filter_fn)(
+		struct repository *r,
+		enum list_objects_filter_situation filter_situation,
+		struct object *obj,
+		const char *pathname,
+		const char *filename,
+		struct filter_context *ctx);
+	void (*free_fn)(void *filter_data);
 
-typedef void (*filter_free_fn)(void *filter_data);
+	struct oidset *omits;
+	void *data;
+};
 
 /*
  * Constructor for the set of defined list-objects filters.
  * Returns a generic "void *filter_data".
  *
  * The returned "filter_fn" will be used by traverse_commit_list()
  * to filter the results.
  *
  * The returned "filter_free_fn" is a destructor for the
  * filter_data.
  */
-void *list_objects_filter__init(
+void list_objects_filter__init(
 	struct oidset *omitted,
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn);
+	struct filter_context *ctx);
+
+static inline void list_objects_filter__release(struct filter_context *ctx) {
+	if (ctx->data && ctx->free_fn)
+		ctx->free_fn(ctx->data);
+	memset(ctx, 0, sizeof(*ctx));
+}
 
 #endif /* LIST_OBJECTS_FILTER_H */
diff --git a/list-objects.c b/list-objects.c
index b5651ddd5b..7a73f7deee 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -11,22 +11,21 @@
 #include "list-objects-filter-options.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "trace.h"
 
 struct traversal_context {
 	struct rev_info *revs;
 	show_object_fn show_object;
 	show_commit_fn show_commit;
 	void *show_data;
-	filter_object_fn filter_fn;
-	void *filter_data;
+	struct filter_context filter_ctx;
 };
 
 static void process_blob(struct traversal_context *ctx,
 			 struct blob *blob,
 			 struct strbuf *path,
 			 const char *name)
 {
 	struct object *obj = &blob->object;
 	size_t pathlen;
 	enum list_objects_filter_result r = LOFR_MARK_SEEN | LOFR_DO_SHOW;
@@ -47,25 +46,25 @@ static void process_blob(struct traversal_context *ctx,
 	 * may cause the actual filter to report an incomplete list
 	 * of missing objects.
 	 */
 	if (ctx->revs->exclude_promisor_objects &&
 	    !has_object_file(&obj->oid) &&
 	    is_promisor_object(&obj->oid))
 		return;
 
 	pathlen = path->len;
 	strbuf_addstr(path, name);
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_BLOB, obj,
-				   path->buf, &path->buf[pathlen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_ctx.filter_fn)
+		r = ctx->filter_ctx.filter_fn(ctx->revs->repo,
+					      LOFS_BLOB, obj,
+					      path->buf, &path->buf[pathlen],
+					      &ctx->filter_ctx);
 	if (r & LOFR_MARK_SEEN)
 		obj->flags |= SEEN;
 	if (r & LOFR_DO_SHOW)
 		ctx->show_object(obj, path->buf, ctx->show_data);
 	strbuf_setlen(path, pathlen);
 }
 
 /*
  * Processing a gitlink entry currently does nothing, since
  * we do not recurse into the subproject.
@@ -179,42 +178,42 @@ static void process_tree(struct traversal_context *ctx,
 		 */
 		if (revs->exclude_promisor_objects &&
 		    is_promisor_object(&obj->oid))
 			return;
 
 		if (!revs->do_not_die_on_missing_tree)
 			die("bad tree object %s", oid_to_hex(&obj->oid));
 	}
 
 	strbuf_addstr(base, name);
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_BEGIN_TREE, obj,
-				   base->buf, &base->buf[baselen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_ctx.filter_fn)
+		r = ctx->filter_ctx.filter_fn(ctx->revs->repo,
+					      LOFS_BEGIN_TREE, obj,
+					      base->buf, &base->buf[baselen],
+					      &ctx->filter_ctx);
 	if (r & LOFR_MARK_SEEN)
 		obj->flags |= SEEN;
 	if (r & LOFR_DO_SHOW)
 		ctx->show_object(obj, base->buf, ctx->show_data);
 	if (base->len)
 		strbuf_addch(base, '/');
 
 	if (r & LOFR_SKIP_TREE)
 		trace_printf("Skipping contents of tree %s...\n", base->buf);
 	else if (!failed_parse)
 		process_tree_contents(ctx, tree, base);
 
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn) {
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_END_TREE, obj,
-				   base->buf, &base->buf[baselen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_ctx.filter_fn) {
+		r = ctx->filter_ctx.filter_fn(ctx->revs->repo,
+					      LOFS_END_TREE, obj,
+					      base->buf, &base->buf[baselen],
+					      &ctx->filter_ctx);
 		if (r & LOFR_MARK_SEEN)
 			obj->flags |= SEEN;
 		if (r & LOFR_DO_SHOW)
 			ctx->show_object(obj, base->buf, ctx->show_data);
 	}
 
 	strbuf_setlen(base, baselen);
 	free_tree_buffer(tree);
 }
 
@@ -395,38 +394,34 @@ static void do_traverse(struct traversal_context *ctx)
 void traverse_commit_list(struct rev_info *revs,
 			  show_commit_fn show_commit,
 			  show_object_fn show_object,
 			  void *show_data)
 {
 	struct traversal_context ctx;
 	ctx.revs = revs;
 	ctx.show_commit = show_commit;
 	ctx.show_object = show_object;
 	ctx.show_data = show_data;
-	ctx.filter_fn = NULL;
-	ctx.filter_data = NULL;
+	memset(&ctx.filter_ctx, 0, sizeof(ctx.filter_ctx));
 	do_traverse(&ctx);
 }
 
 void traverse_commit_list_filtered(
 	struct list_objects_filter_options *filter_options,
 	struct rev_info *revs,
 	show_commit_fn show_commit,
 	show_object_fn show_object,
 	void *show_data,
 	struct oidset *omitted)
 {
 	struct traversal_context ctx;
-	filter_free_fn filter_free_fn = NULL;
+	memset(&ctx, 0, sizeof(ctx));
 
 	ctx.revs = revs;
 	ctx.show_object = show_object;
 	ctx.show_commit = show_commit;
 	ctx.show_data = show_data;
-	ctx.filter_fn = NULL;
 
-	ctx.filter_data = list_objects_filter__init(omitted, filter_options,
-						    &ctx.filter_fn, &filter_free_fn);
+	list_objects_filter__init(omitted, filter_options, &ctx.filter_ctx);
 	do_traverse(&ctx);
-	if (ctx.filter_data && filter_free_fn)
-		filter_free_fn(ctx.filter_data);
+	list_objects_filter__release(&ctx.filter_ctx);
 }

list-objects-filter-options.h, list-objects-filter.c, list-objects-filter.h, list-objects.c

diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index e3adc78ebf..ac320c3312 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -2,25 +2,44 @@
 #define LIST_OBJECTS_FILTER_OPTIONS_H
 
 #include "parse-options.h"
 #include "strbuf.h"
 
 /*
  * The list of defined filters for list-objects.
  */
 enum list_objects_filter_choice {
 	LOFC_DISABLED = 0,
+
+	/* A filter for list-objects to omit ALL blobs from the traversal. */
 	LOFC_BLOB_NONE,
+
+	/* A filter for list-objects to omit large blobs. */
 	LOFC_BLOB_LIMIT,
+
+	/*
+	 * A filter for list-objects to omit ALL trees and blobs from the
+	 * traversal.
+	 */
 	LOFC_TREE_DEPTH,
+
+	/*
+	 * Filters driven by a sparse-checkout specification to only include
+	 * blobs that a sparse checkout would populate.
+	 *
+	 * The sparse-checkout spec can be loaded from a blob with the given
+	 * OID or from a local pathname.  We allow an OID because the repo may
+	 * be bare or we may be doing the filtering on the server.
+	 */
 	LOFC_SPARSE_OID,
 	LOFC_SPARSE_PATH,
+
 	LOFC__COUNT /* must be last */
 };
 
 struct list_objects_filter_options {
 	/*
 	 * 'filter_spec' is the raw argument value given on the command line
 	 * or protocol request.  (The part after the "--keyword=".)  For
 	 * commands that launch filtering sub-processes, or for communication
 	 * over the network, don't use this value; use the result of
 	 * expand_list_objects_filter_spec() instead.
diff --git a/list-objects-filter.c b/list-objects-filter.c
index ee449de3f7..334b0d959b 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -19,38 +19,67 @@
  * FILTER_SHOWN_BUT_REVISIT -- we set this bit on tree objects
  * that have been shown, but should be revisited if they appear
  * in the traversal (until we mark it SEEN).  This is a way to
  * let us silently de-dup calls to show() in the caller.  This
  * is subtly different from the "revision.h:SHOWN" and the
  * "sha1-name.c:ONELINE_SEEN" bits.  And also different from
  * the non-de-dup usage in pack-bitmap.c
  */
 #define FILTER_SHOWN_BUT_REVISIT (1<<21)
 
-/*
- * A filter for list-objects to omit ALL blobs from the traversal.
- * And to OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_blobs_none_data {
+struct filter_data {
+	/* Used by all filter types. */
 	struct oidset *omits;
+
+	enum list_objects_filter_result (*filter_object_fn)(
+		struct repository *r,
+		enum list_objects_filter_situation filter_situation,
+		struct object *obj,
+		const char *pathname,
+		const char *filename,
+		struct filter_data *filter_data);
+
+	/* BEGIN tree:<depth> filter data */
+
+	/*
+	 * Maps trees to the minimum depth at which they were seen. It is not
+	 * necessary to re-traverse a tree at deeper or equal depths than it has
+	 * already been traversed.
+	 *
+	 * We can't use LOFR_MARK_SEEN for tree objects since this will prevent
+	 * it from being traversed at shallower depths.
+	 */
+	struct oidmap seen_at_depth;
+
+	unsigned long exclude_depth;
+	unsigned long current_depth;
+
+	/* BEGIN blobs:limit=<limit> filter data */
+
+	unsigned long max_bytes;
+
+	/* BEGIN sparse:... filter data */
+
+	struct exclude_list el;
+
+	size_t nr, alloc;
+	struct frame *array_frame;
 };
 
 static enum list_objects_filter_result filter_blobs_none(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_blobs_none_data *filter_data = filter_data_;
-
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		/* always include all tree objects */
 		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 
 	case LOFS_END_TREE:
@@ -60,84 +89,55 @@ static enum list_objects_filter_result filter_blobs_none(
 	case LOFS_BLOB:
 		assert(obj->type == OBJ_BLOB);
 		assert((obj->flags & SEEN) == 0);
 
 		if (filter_data->omits)
 			oidset_insert(filter_data->omits, &obj->oid);
 		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
 	}
 }
 
-static void *filter_blobs_none__init(
-	struct oidset *omitted,
+static void filter_blobs_none__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_blobs_none_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
-
-	*filter_fn = filter_blobs_none;
-	*filter_free_fn = free;
-	return d;
+	d->filter_object_fn = filter_blobs_none;
 }
 
-/*
- * A filter for list-objects to omit ALL trees and blobs from the traversal.
- * Can OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_trees_depth_data {
-	struct oidset *omits;
-
-	/*
-	 * Maps trees to the minimum depth at which they were seen. It is not
-	 * necessary to re-traverse a tree at deeper or equal depths than it has
-	 * already been traversed.
-	 *
-	 * We can't use LOFR_MARK_SEEN for tree objects since this will prevent
-	 * it from being traversed at shallower depths.
-	 */
-	struct oidmap seen_at_depth;
-
-	unsigned long exclude_depth;
-	unsigned long current_depth;
-};
-
 struct seen_map_entry {
 	struct oidmap_entry base;
 	size_t depth;
 };
 
 /* Returns 1 if the oid was in the omits set before it was invoked. */
 static int filter_trees_update_omits(
 	struct object *obj,
-	struct filter_trees_depth_data *filter_data,
+	struct filter_data *filter_data,
 	int include_it)
 {
 	if (!filter_data->omits)
 		return 0;
 
 	if (include_it)
 		return oidset_remove(filter_data->omits, &obj->oid);
 	else
 		return oidset_insert(filter_data->omits, &obj->oid);
 }
 
 static enum list_objects_filter_result filter_trees_depth(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_trees_depth_data *filter_data = filter_data_;
 	struct seen_map_entry *seen_info;
 	int include_it = filter_data->current_depth <
 		filter_data->exclude_depth;
 	int filter_res;
 	int already_seen;
 
 	/*
 	 * Note that we do not use _MARK_SEEN in order to allow re-traversal in
 	 * case we encounter a tree or blob again at a shallower depth.
 	 */
@@ -186,63 +186,38 @@ static enum list_objects_filter_result filter_trees_depth(
 				filter_res = LOFR_ZERO;
 			else
 				filter_res = LOFR_SKIP_TREE;
 		}
 
 		filter_data->current_depth++;
 		return filter_res;
 	}
 }
 
-static void filter_trees_free(void *filter_data) {
-	struct filter_trees_depth_data *d = filter_data;
-	if (!d)
-		return;
-	oidmap_free(&d->seen_at_depth, 1);
-	free(d);
-}
-
-static void *filter_trees_depth__init(
-	struct oidset *omitted,
+static void filter_trees_depth__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_trees_depth_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	oidmap_init(&d->seen_at_depth, 0);
 	d->exclude_depth = filter_options->tree_exclude_depth;
 	d->current_depth = 0;
-
-	*filter_fn = filter_trees_depth;
-	*filter_free_fn = filter_trees_free;
-	return d;
+	d->filter_object_fn = filter_trees_depth;
 }
 
-/*
- * A filter for list-objects to omit large blobs.
- * And to OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_blobs_limit_data {
-	struct oidset *omits;
-	unsigned long max_bytes;
-};
-
 static enum list_objects_filter_result filter_blobs_limit(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_blobs_limit_data *filter_data = filter_data_;
 	unsigned long object_length;
 	enum object_type t;
 
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		/* always include all tree objects */
@@ -274,81 +249,57 @@ static enum list_objects_filter_result filter_blobs_limit(
 			oidset_insert(filter_data->omits, &obj->oid);
 		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
 	}
 
 include_it:
 	if (filter_data->omits)
 		oidset_remove(filter_data->omits, &obj->oid);
 	return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 }
 
-static void *filter_blobs_limit__init(
-	struct oidset *omitted,
+static void filter_blobs_limit__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_blobs_limit_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	d->max_bytes = filter_options->blob_limit_value;
-
-	*filter_fn = filter_blobs_limit;
-	*filter_free_fn = free;
-	return d;
+	d->filter_object_fn = filter_blobs_limit;
 }
 
-/*
- * A filter driven by a sparse-checkout specification to only
- * include blobs that a sparse checkout would populate.
- *
- * The sparse-checkout spec can be loaded from a blob with the
- * given OID or from a local pathname.  We allow an OID because
- * the repo may be bare or we may be doing the filtering on the
- * server.
- */
+/* For use with sparse checkout filters. */
 struct frame {
 	/*
 	 * defval is the usual default include/exclude value that
 	 * should be inherited as we recurse into directories based
 	 * upon pattern matching of the directory itself or of a
 	 * containing directory.
 	 */
 	int defval;
 
 	/*
 	 * 1 if the directory (recursively) contains any provisionally
 	 * omitted objects.
 	 *
 	 * 0 if everything (recursively) contained in this directory
 	 * has been explicitly included (SHOWN) in the result and
 	 * the directory may be short-cut later in the traversal.
 	 */
 	unsigned child_prov_omit : 1;
 };
 
-struct filter_sparse_data {
-	struct oidset *omits;
-	struct exclude_list el;
-
-	size_t nr, alloc;
-	struct frame *array_frame;
-};
-
 static enum list_objects_filter_result filter_sparse(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_sparse_data *filter_data = filter_data_;
 	int val, dtype;
 	struct frame *frame;
 
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		dtype = DT_DIR;
@@ -442,100 +393,96 @@ static enum list_objects_filter_result filter_sparse(
 		/*
 		 * Remember that at least 1 blob in this tree was
 		 * provisionally omitted.  This prevents us from short
 		 * cutting the tree in future iterations.
 		 */
 		frame->child_prov_omit = 1;
 		return LOFR_ZERO;
 	}
 }
 
-
-static void filter_sparse_free(void *filter_data)
-{
-	struct filter_sparse_data *d = filter_data;
-	/* TODO free contents of 'd' */
-	free(d);
-}
-
-static void *filter_sparse_oid__init(
-	struct oidset *omitted,
+static void filter_sparse_oid__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	if (add_excludes_from_blob_to_list(filter_options->sparse_oid_value,
 					   NULL, 0, &d->el) < 0)
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
-	*filter_fn = filter_sparse;
-	*filter_free_fn = filter_sparse_free;
-	return d;
+	d->filter_object_fn = filter_sparse;
 }
 
-static void *filter_sparse_path__init(
-	struct oidset *omitted,
+static void filter_sparse_path__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	if (add_excludes_from_file_to_list(filter_options->sparse_path_value,
 					   NULL, 0, &d->el, NULL) < 0)
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
-	*filter_fn = filter_sparse;
-	*filter_free_fn = filter_sparse_free;
-	return d;
+	d->filter_object_fn = filter_sparse;
 }
 
-typedef void *(*filter_init_fn)(
-	struct oidset *omitted,
+typedef void (*filter_init_fn)(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn);
+	struct filter_data *filter_data);
 
 /*
  * Must match "enum list_objects_filter_choice".
  */
 static filter_init_fn s_filters[] = {
 	NULL,
 	filter_blobs_none__init,
 	filter_blobs_limit__init,
 	filter_trees_depth__init,
 	filter_sparse_oid__init,
 	filter_sparse_path__init,
 };
 
-void *list_objects_filter__init(
+struct filter_data *list_objects_filter__init(
 	struct oidset *omitted,
-	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct list_objects_filter_options *filter_options)
 {
 	filter_init_fn init_fn;
+	struct filter_data *filter_data;
 
 	assert((sizeof(s_filters) / sizeof(s_filters[0])) == LOFC__COUNT);
 
 	if (filter_options->choice >= LOFC__COUNT)
 		BUG("invalid list-objects filter choice: %d",
 		    filter_options->choice);
 
 	init_fn = s_filters[filter_options->choice];
-	if (init_fn)
-		return init_fn(omitted, filter_options,
-			       filter_fn, filter_free_fn);
-	*filter_fn = NULL;
-	*filter_free_fn = NULL;
-	return NULL;
+	if (!init_fn)
+		return NULL;
+
+	filter_data = xcalloc(1, sizeof(*filter_data));
+	filter_data->omits = omitted;
+	init_fn(filter_options, filter_data);
+
+	return filter_data;
+}
+
+enum list_objects_filter_result list_objects_filter__filter_object(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct filter_data *filter_data)
+{
+	return filter_data->filter_object_fn(
+		r, filter_situation, obj, pathname, filename, filter_data);
+}
+
+void list_objects_filter__free(struct filter_data *d) {
+	oidmap_free(&d->seen_at_depth, 1);
+	free(d);
 }
diff --git a/list-objects-filter.h b/list-objects-filter.h
index 1d45a4ad57..2bc59147a7 100644
--- a/list-objects-filter.h
+++ b/list-objects-filter.h
@@ -53,37 +53,34 @@ enum list_objects_filter_result {
 	LOFR_DO_SHOW   = 1<<1,
 	LOFR_SKIP_TREE = 1<<2,
 };
 
 enum list_objects_filter_situation {
 	LOFS_BEGIN_TREE,
 	LOFS_END_TREE,
 	LOFS_BLOB
 };
 
-typedef enum list_objects_filter_result (*filter_object_fn)(
-	struct repository *r,
-	enum list_objects_filter_situation filter_situation,
-	struct object *obj,
-	const char *pathname,
-	const char *filename,
-	void *filter_data);
-
-typedef void (*filter_free_fn)(void *filter_data);
+struct filter_data;
 
 /*
  * Constructor for the set of defined list-objects filters.
  * Returns a generic "void *filter_data".
  *
  * The returned "filter_fn" will be used by traverse_commit_list()
  * to filter the results.
- *
- * The returned "filter_free_fn" is a destructor for the
- * filter_data.
  */
-void *list_objects_filter__init(
+struct filter_data *list_objects_filter__init(
 	struct oidset *omitted,
-	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn);
+	struct list_objects_filter_options *filter_options);
+
+enum list_objects_filter_result list_objects_filter__filter_object(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct filter_data *filter_data);
+
+void list_objects_filter__free(struct filter_data *filter_data);
 
 #endif /* LIST_OBJECTS_FILTER_H */
diff --git a/list-objects.c b/list-objects.c
index b5651ddd5b..9d5cd1b1e5 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -11,22 +11,21 @@
 #include "list-objects-filter-options.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "trace.h"
 
 struct traversal_context {
 	struct rev_info *revs;
 	show_object_fn show_object;
 	show_commit_fn show_commit;
 	void *show_data;
-	filter_object_fn filter_fn;
-	void *filter_data;
+	struct filter_data *filter_data;
 };
 
 static void process_blob(struct traversal_context *ctx,
 			 struct blob *blob,
 			 struct strbuf *path,
 			 const char *name)
 {
 	struct object *obj = &blob->object;
 	size_t pathlen;
 	enum list_objects_filter_result r = LOFR_MARK_SEEN | LOFR_DO_SHOW;
@@ -47,25 +46,26 @@ static void process_blob(struct traversal_context *ctx,
 	 * may cause the actual filter to report an incomplete list
 	 * of missing objects.
 	 */
 	if (ctx->revs->exclude_promisor_objects &&
 	    !has_object_file(&obj->oid) &&
 	    is_promisor_object(&obj->oid))
 		return;
 
 	pathlen = path->len;
 	strbuf_addstr(path, name);
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_BLOB, obj,
-				   path->buf, &path->buf[pathlen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_data)
+		r = list_objects_filter__filter_object(
+			ctx->revs->repo,
+			LOFS_BLOB, obj,
+			path->buf, &path->buf[pathlen],
+			ctx->filter_data);
 	if (r & LOFR_MARK_SEEN)
 		obj->flags |= SEEN;
 	if (r & LOFR_DO_SHOW)
 		ctx->show_object(obj, path->buf, ctx->show_data);
 	strbuf_setlen(path, pathlen);
 }
 
 /*
  * Processing a gitlink entry currently does nothing, since
  * we do not recurse into the subproject.
@@ -179,42 +179,44 @@ static void process_tree(struct traversal_context *ctx,
 		 */
 		if (revs->exclude_promisor_objects &&
 		    is_promisor_object(&obj->oid))
 			return;
 
 		if (!revs->do_not_die_on_missing_tree)
 			die("bad tree object %s", oid_to_hex(&obj->oid));
 	}
 
 	strbuf_addstr(base, name);
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_BEGIN_TREE, obj,
-				   base->buf, &base->buf[baselen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_data)
+		r = list_objects_filter__filter_object(
+			ctx->revs->repo,
+			LOFS_BEGIN_TREE, obj,
+			base->buf, &base->buf[baselen],
+			ctx->filter_data);
 	if (r & LOFR_MARK_SEEN)
 		obj->flags |= SEEN;
 	if (r & LOFR_DO_SHOW)
 		ctx->show_object(obj, base->buf, ctx->show_data);
 	if (base->len)
 		strbuf_addch(base, '/');
 
 	if (r & LOFR_SKIP_TREE)
 		trace_printf("Skipping contents of tree %s...\n", base->buf);
 	else if (!failed_parse)
 		process_tree_contents(ctx, tree, base);
 
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn) {
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_END_TREE, obj,
-				   base->buf, &base->buf[baselen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_data) {
+		r = list_objects_filter__filter_object(
+			ctx->revs->repo,
+			LOFS_END_TREE, obj,
+			base->buf, &base->buf[baselen],
+			ctx->filter_data);
 		if (r & LOFR_MARK_SEEN)
 			obj->flags |= SEEN;
 		if (r & LOFR_DO_SHOW)
 			ctx->show_object(obj, base->buf, ctx->show_data);
 	}
 
 	strbuf_setlen(base, baselen);
 	free_tree_buffer(tree);
 }
 
@@ -395,38 +397,32 @@ static void do_traverse(struct traversal_context *ctx)
 void traverse_commit_list(struct rev_info *revs,
 			  show_commit_fn show_commit,
 			  show_object_fn show_object,
 			  void *show_data)
 {
 	struct traversal_context ctx;
 	ctx.revs = revs;
 	ctx.show_commit = show_commit;
 	ctx.show_object = show_object;
 	ctx.show_data = show_data;
-	ctx.filter_fn = NULL;
 	ctx.filter_data = NULL;
 	do_traverse(&ctx);
 }
 
 void traverse_commit_list_filtered(
 	struct list_objects_filter_options *filter_options,
 	struct rev_info *revs,
 	show_commit_fn show_commit,
 	show_object_fn show_object,
 	void *show_data,
 	struct oidset *omitted)
 {
 	struct traversal_context ctx;
-	filter_free_fn filter_free_fn = NULL;
 
 	ctx.revs = revs;
 	ctx.show_object = show_object;
 	ctx.show_commit = show_commit;
 	ctx.show_data = show_data;
-	ctx.filter_fn = NULL;
 
-	ctx.filter_data = list_objects_filter__init(omitted, filter_options,
-						    &ctx.filter_fn, &filter_free_fn);
+	ctx.filter_data = list_objects_filter__init(omitted, filter_options);
 	do_traverse(&ctx);
-	if (ctx.filter_data && filter_free_fn)
-		filter_free_fn(ctx.filter_data);
 }

list-objects-filter-options.h, list-objects-filter.c, list-objects-filter.h, list-objects.c

diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index e3adc78ebf..ac320c3312 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -2,25 +2,44 @@
 #define LIST_OBJECTS_FILTER_OPTIONS_H
 
 #include "parse-options.h"
 #include "strbuf.h"
 
 /*
  * The list of defined filters for list-objects.
  */
 enum list_objects_filter_choice {
 	LOFC_DISABLED = 0,
+
+	/* A filter for list-objects to omit ALL blobs from the traversal. */
 	LOFC_BLOB_NONE,
+
+	/* A filter for list-objects to omit large blobs. */
 	LOFC_BLOB_LIMIT,
+
+	/*
+	 * A filter for list-objects to omit ALL trees and blobs from the
+	 * traversal.
+	 */
 	LOFC_TREE_DEPTH,
+
+	/*
+	 * Filters driven by a sparse-checkout specification to only include
+	 * blobs that a sparse checkout would populate.
+	 *
+	 * The sparse-checkout spec can be loaded from a blob with the given
+	 * OID or from a local pathname.  We allow an OID because the repo may
+	 * be bare or we may be doing the filtering on the server.
+	 */
 	LOFC_SPARSE_OID,
 	LOFC_SPARSE_PATH,
+
 	LOFC__COUNT /* must be last */
 };
 
 struct list_objects_filter_options {
 	/*
 	 * 'filter_spec' is the raw argument value given on the command line
 	 * or protocol request.  (The part after the "--keyword=".)  For
 	 * commands that launch filtering sub-processes, or for communication
 	 * over the network, don't use this value; use the result of
 	 * expand_list_objects_filter_spec() instead.
diff --git a/list-objects-filter.c b/list-objects-filter.c
index ee449de3f7..d35bd5c904 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -19,38 +19,73 @@
  * FILTER_SHOWN_BUT_REVISIT -- we set this bit on tree objects
  * that have been shown, but should be revisited if they appear
  * in the traversal (until we mark it SEEN).  This is a way to
  * let us silently de-dup calls to show() in the caller.  This
  * is subtly different from the "revision.h:SHOWN" and the
  * "sha1-name.c:ONELINE_SEEN" bits.  And also different from
  * the non-de-dup usage in pack-bitmap.c
  */
 #define FILTER_SHOWN_BUT_REVISIT (1<<21)
 
-/*
- * A filter for list-objects to omit ALL blobs from the traversal.
- * And to OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_blobs_none_data {
+struct filter_data {
+	/* Used by all filter types. */
 	struct oidset *omits;
+
+	enum list_objects_filter_result (*filter_object_fn)(
+		struct repository *r,
+		enum list_objects_filter_situation filter_situation,
+		struct object *obj,
+		const char *pathname,
+		const char *filename,
+		struct filter_data *filter_data);
+
+	void (*filter_clear_fn)(struct filter_data *filter_data);
+
+	union {
+		struct {
+			/*
+			 * Maps trees to the minimum depth at which they were
+			 * seen. It is not necessary to re-traverse a tree at
+			 * deeper or equal depths than it has already been
+			 * traversed.
+			 *
+			 * We can't use LOFR_MARK_SEEN for tree objects since
+			 * this will prevent it from being traversed at
+			 * shallower depths.
+			 */
+			struct oidmap seen_at_depth;
+
+			unsigned long exclude_depth;
+			unsigned long current_depth;
+		};
+
+		struct {
+			unsigned long max_bytes;
+		};
+
+		struct {
+			struct exclude_list el;
+
+			size_t nr, alloc;
+			struct frame *array_frame;
+		};
+	};
 };
 
 static enum list_objects_filter_result filter_blobs_none(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_blobs_none_data *filter_data = filter_data_;
-
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		/* always include all tree objects */
 		return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 
 	case LOFS_END_TREE:
@@ -60,84 +95,55 @@ static enum list_objects_filter_result filter_blobs_none(
 	case LOFS_BLOB:
 		assert(obj->type == OBJ_BLOB);
 		assert((obj->flags & SEEN) == 0);
 
 		if (filter_data->omits)
 			oidset_insert(filter_data->omits, &obj->oid);
 		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
 	}
 }
 
-static void *filter_blobs_none__init(
-	struct oidset *omitted,
+static void filter_blobs_none__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_blobs_none_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
-
-	*filter_fn = filter_blobs_none;
-	*filter_free_fn = free;
-	return d;
+	d->filter_object_fn = filter_blobs_none;
 }
 
-/*
- * A filter for list-objects to omit ALL trees and blobs from the traversal.
- * Can OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_trees_depth_data {
-	struct oidset *omits;
-
-	/*
-	 * Maps trees to the minimum depth at which they were seen. It is not
-	 * necessary to re-traverse a tree at deeper or equal depths than it has
-	 * already been traversed.
-	 *
-	 * We can't use LOFR_MARK_SEEN for tree objects since this will prevent
-	 * it from being traversed at shallower depths.
-	 */
-	struct oidmap seen_at_depth;
-
-	unsigned long exclude_depth;
-	unsigned long current_depth;
-};
-
 struct seen_map_entry {
 	struct oidmap_entry base;
 	size_t depth;
 };
 
 /* Returns 1 if the oid was in the omits set before it was invoked. */
 static int filter_trees_update_omits(
 	struct object *obj,
-	struct filter_trees_depth_data *filter_data,
+	struct filter_data *filter_data,
 	int include_it)
 {
 	if (!filter_data->omits)
 		return 0;
 
 	if (include_it)
 		return oidset_remove(filter_data->omits, &obj->oid);
 	else
 		return oidset_insert(filter_data->omits, &obj->oid);
 }
 
 static enum list_objects_filter_result filter_trees_depth(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_trees_depth_data *filter_data = filter_data_;
 	struct seen_map_entry *seen_info;
 	int include_it = filter_data->current_depth <
 		filter_data->exclude_depth;
 	int filter_res;
 	int already_seen;
 
 	/*
 	 * Note that we do not use _MARK_SEEN in order to allow re-traversal in
 	 * case we encounter a tree or blob again at a shallower depth.
 	 */
@@ -186,63 +192,44 @@ static enum list_objects_filter_result filter_trees_depth(
 				filter_res = LOFR_ZERO;
 			else
 				filter_res = LOFR_SKIP_TREE;
 		}
 
 		filter_data->current_depth++;
 		return filter_res;
 	}
 }
 
-static void filter_trees_free(void *filter_data) {
-	struct filter_trees_depth_data *d = filter_data;
-	if (!d)
-		return;
-	oidmap_free(&d->seen_at_depth, 1);
-	free(d);
+static void filter_trees_clear(struct filter_data *filter_data)
+{
+	oidmap_free(&filter_data->seen_at_depth, 1);
 }
 
-static void *filter_trees_depth__init(
-	struct oidset *omitted,
+static void filter_trees_depth__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_trees_depth_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	oidmap_init(&d->seen_at_depth, 0);
 	d->exclude_depth = filter_options->tree_exclude_depth;
 	d->current_depth = 0;
-
-	*filter_fn = filter_trees_depth;
-	*filter_free_fn = filter_trees_free;
-	return d;
+	d->filter_object_fn = filter_trees_depth;
+	d->filter_clear_fn = filter_trees_clear;
 }
 
-/*
- * A filter for list-objects to omit large blobs.
- * And to OPTIONALLY collect a list of the omitted OIDs.
- */
-struct filter_blobs_limit_data {
-	struct oidset *omits;
-	unsigned long max_bytes;
-};
-
 static enum list_objects_filter_result filter_blobs_limit(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_blobs_limit_data *filter_data = filter_data_;
 	unsigned long object_length;
 	enum object_type t;
 
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		/* always include all tree objects */
@@ -274,81 +261,57 @@ static enum list_objects_filter_result filter_blobs_limit(
 			oidset_insert(filter_data->omits, &obj->oid);
 		return LOFR_MARK_SEEN; /* but not LOFR_DO_SHOW (hard omit) */
 	}
 
 include_it:
 	if (filter_data->omits)
 		oidset_remove(filter_data->omits, &obj->oid);
 	return LOFR_MARK_SEEN | LOFR_DO_SHOW;
 }
 
-static void *filter_blobs_limit__init(
-	struct oidset *omitted,
+static void filter_blobs_limit__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_blobs_limit_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	d->max_bytes = filter_options->blob_limit_value;
-
-	*filter_fn = filter_blobs_limit;
-	*filter_free_fn = free;
-	return d;
+	d->filter_object_fn = filter_blobs_limit;
 }
 
-/*
- * A filter driven by a sparse-checkout specification to only
- * include blobs that a sparse checkout would populate.
- *
- * The sparse-checkout spec can be loaded from a blob with the
- * given OID or from a local pathname.  We allow an OID because
- * the repo may be bare or we may be doing the filtering on the
- * server.
- */
+/* For use with sparse checkout filters. */
 struct frame {
 	/*
 	 * defval is the usual default include/exclude value that
 	 * should be inherited as we recurse into directories based
 	 * upon pattern matching of the directory itself or of a
 	 * containing directory.
 	 */
 	int defval;
 
 	/*
 	 * 1 if the directory (recursively) contains any provisionally
 	 * omitted objects.
 	 *
 	 * 0 if everything (recursively) contained in this directory
 	 * has been explicitly included (SHOWN) in the result and
 	 * the directory may be short-cut later in the traversal.
 	 */
 	unsigned child_prov_omit : 1;
 };
 
-struct filter_sparse_data {
-	struct oidset *omits;
-	struct exclude_list el;
-
-	size_t nr, alloc;
-	struct frame *array_frame;
-};
-
 static enum list_objects_filter_result filter_sparse(
 	struct repository *r,
 	enum list_objects_filter_situation filter_situation,
 	struct object *obj,
 	const char *pathname,
 	const char *filename,
-	void *filter_data_)
+	struct filter_data *filter_data)
 {
-	struct filter_sparse_data *filter_data = filter_data_;
 	int val, dtype;
 	struct frame *frame;
 
 	switch (filter_situation) {
 	default:
 		BUG("unknown filter_situation: %d", filter_situation);
 
 	case LOFS_BEGIN_TREE:
 		assert(obj->type == OBJ_TREE);
 		dtype = DT_DIR;
@@ -442,100 +405,104 @@ static enum list_objects_filter_result filter_sparse(
 		/*
 		 * Remember that at least 1 blob in this tree was
 		 * provisionally omitted.  This prevents us from short
 		 * cutting the tree in future iterations.
 		 */
 		frame->child_prov_omit = 1;
 		return LOFR_ZERO;
 	}
 }
 
-
-static void filter_sparse_free(void *filter_data)
+static void filter_sparse_clear(struct filter_data *filter_data)
 {
-	struct filter_sparse_data *d = filter_data;
-	/* TODO free contents of 'd' */
-	free(d);
+	FREE_AND_NULL(filter_data->array_frame);
 }
 
-static void *filter_sparse_oid__init(
-	struct oidset *omitted,
+static void filter_sparse_oid__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	if (add_excludes_from_blob_to_list(filter_options->sparse_oid_value,
 					   NULL, 0, &d->el) < 0)
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
-	*filter_fn = filter_sparse;
-	*filter_free_fn = filter_sparse_free;
-	return d;
+	d->filter_object_fn = filter_sparse;
+	d->filter_clear_fn = filter_sparse_clear;
 }
 
-static void *filter_sparse_path__init(
-	struct oidset *omitted,
+static void filter_sparse_path__init(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct filter_data *d)
 {
-	struct filter_sparse_data *d = xcalloc(1, sizeof(*d));
-	d->omits = omitted;
 	if (add_excludes_from_file_to_list(filter_options->sparse_path_value,
 					   NULL, 0, &d->el, NULL) < 0)
 		die("could not load filter specification");
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
-	*filter_fn = filter_sparse;
-	*filter_free_fn = filter_sparse_free;
-	return d;
+	d->filter_object_fn = filter_sparse;
+	d->filter_clear_fn = filter_sparse_clear;
 }
 
-typedef void *(*filter_init_fn)(
-	struct oidset *omitted,
+typedef void (*filter_init_fn)(
 	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn);
+	struct filter_data *filter_data);
 
 /*
  * Must match "enum list_objects_filter_choice".
  */
 static filter_init_fn s_filters[] = {
 	NULL,
 	filter_blobs_none__init,
 	filter_blobs_limit__init,
 	filter_trees_depth__init,
 	filter_sparse_oid__init,
 	filter_sparse_path__init,
 };
 
-void *list_objects_filter__init(
+struct filter_data *list_objects_filter__init(
 	struct oidset *omitted,
-	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn)
+	struct list_objects_filter_options *filter_options)
 {
 	filter_init_fn init_fn;
+	struct filter_data *filter_data;
 
 	assert((sizeof(s_filters) / sizeof(s_filters[0])) == LOFC__COUNT);
 
 	if (filter_options->choice >= LOFC__COUNT)
 		BUG("invalid list-objects filter choice: %d",
 		    filter_options->choice);
 
 	init_fn = s_filters[filter_options->choice];
-	if (init_fn)
-		return init_fn(omitted, filter_options,
-			       filter_fn, filter_free_fn);
-	*filter_fn = NULL;
-	*filter_free_fn = NULL;
-	return NULL;
+	if (!init_fn)
+		return NULL;
+
+	filter_data = xcalloc(1, sizeof(*filter_data));
+	filter_data->omits = omitted;
+	init_fn(filter_options, filter_data);
+
+	return filter_data;
+}
+
+enum list_objects_filter_result list_objects_filter__filter_object(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct filter_data *filter_data)
+{
+	return filter_data->filter_object_fn(
+		r, filter_situation, obj, pathname, filename, filter_data);
+}
+
+void list_objects_filter__free(struct filter_data *d) {
+	if (d->filter_clear_fn)
+		d->filter_clear_fn(d);
+	FREE_AND_NULL(d);
 }
diff --git a/list-objects-filter.h b/list-objects-filter.h
index 1d45a4ad57..2bc59147a7 100644
--- a/list-objects-filter.h
+++ b/list-objects-filter.h
@@ -53,37 +53,34 @@ enum list_objects_filter_result {
 	LOFR_DO_SHOW   = 1<<1,
 	LOFR_SKIP_TREE = 1<<2,
 };
 
 enum list_objects_filter_situation {
 	LOFS_BEGIN_TREE,
 	LOFS_END_TREE,
 	LOFS_BLOB
 };
 
-typedef enum list_objects_filter_result (*filter_object_fn)(
-	struct repository *r,
-	enum list_objects_filter_situation filter_situation,
-	struct object *obj,
-	const char *pathname,
-	const char *filename,
-	void *filter_data);
-
-typedef void (*filter_free_fn)(void *filter_data);
+struct filter_data;
 
 /*
  * Constructor for the set of defined list-objects filters.
  * Returns a generic "void *filter_data".
  *
  * The returned "filter_fn" will be used by traverse_commit_list()
  * to filter the results.
- *
- * The returned "filter_free_fn" is a destructor for the
- * filter_data.
  */
-void *list_objects_filter__init(
+struct filter_data *list_objects_filter__init(
 	struct oidset *omitted,
-	struct list_objects_filter_options *filter_options,
-	filter_object_fn *filter_fn,
-	filter_free_fn *filter_free_fn);
+	struct list_objects_filter_options *filter_options);
+
+enum list_objects_filter_result list_objects_filter__filter_object(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct filter_data *filter_data);
+
+void list_objects_filter__free(struct filter_data *filter_data);
 
 #endif /* LIST_OBJECTS_FILTER_H */
diff --git a/list-objects.c b/list-objects.c
index b5651ddd5b..a5502a226d 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -11,22 +11,21 @@
 #include "list-objects-filter-options.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "trace.h"
 
 struct traversal_context {
 	struct rev_info *revs;
 	show_object_fn show_object;
 	show_commit_fn show_commit;
 	void *show_data;
-	filter_object_fn filter_fn;
-	void *filter_data;
+	struct filter_data *filter_data;
 };
 
 static void process_blob(struct traversal_context *ctx,
 			 struct blob *blob,
 			 struct strbuf *path,
 			 const char *name)
 {
 	struct object *obj = &blob->object;
 	size_t pathlen;
 	enum list_objects_filter_result r = LOFR_MARK_SEEN | LOFR_DO_SHOW;
@@ -47,25 +46,26 @@ static void process_blob(struct traversal_context *ctx,
 	 * may cause the actual filter to report an incomplete list
 	 * of missing objects.
 	 */
 	if (ctx->revs->exclude_promisor_objects &&
 	    !has_object_file(&obj->oid) &&
 	    is_promisor_object(&obj->oid))
 		return;
 
 	pathlen = path->len;
 	strbuf_addstr(path, name);
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_BLOB, obj,
-				   path->buf, &path->buf[pathlen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_data)
+		r = list_objects_filter__filter_object(
+			ctx->revs->repo,
+			LOFS_BLOB, obj,
+			path->buf, &path->buf[pathlen],
+			ctx->filter_data);
 	if (r & LOFR_MARK_SEEN)
 		obj->flags |= SEEN;
 	if (r & LOFR_DO_SHOW)
 		ctx->show_object(obj, path->buf, ctx->show_data);
 	strbuf_setlen(path, pathlen);
 }
 
 /*
  * Processing a gitlink entry currently does nothing, since
  * we do not recurse into the subproject.
@@ -179,42 +179,44 @@ static void process_tree(struct traversal_context *ctx,
 		 */
 		if (revs->exclude_promisor_objects &&
 		    is_promisor_object(&obj->oid))
 			return;
 
 		if (!revs->do_not_die_on_missing_tree)
 			die("bad tree object %s", oid_to_hex(&obj->oid));
 	}
 
 	strbuf_addstr(base, name);
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn)
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_BEGIN_TREE, obj,
-				   base->buf, &base->buf[baselen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_data)
+		r = list_objects_filter__filter_object(
+			ctx->revs->repo,
+			LOFS_BEGIN_TREE, obj,
+			base->buf, &base->buf[baselen],
+			ctx->filter_data);
 	if (r & LOFR_MARK_SEEN)
 		obj->flags |= SEEN;
 	if (r & LOFR_DO_SHOW)
 		ctx->show_object(obj, base->buf, ctx->show_data);
 	if (base->len)
 		strbuf_addch(base, '/');
 
 	if (r & LOFR_SKIP_TREE)
 		trace_printf("Skipping contents of tree %s...\n", base->buf);
 	else if (!failed_parse)
 		process_tree_contents(ctx, tree, base);
 
-	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_fn) {
-		r = ctx->filter_fn(ctx->revs->repo,
-				   LOFS_END_TREE, obj,
-				   base->buf, &base->buf[baselen],
-				   ctx->filter_data);
+	if ((obj->flags & NOT_USER_GIVEN) && ctx->filter_data) {
+		r = list_objects_filter__filter_object(
+			ctx->revs->repo,
+			LOFS_END_TREE, obj,
+			base->buf, &base->buf[baselen],
+			ctx->filter_data);
 		if (r & LOFR_MARK_SEEN)
 			obj->flags |= SEEN;
 		if (r & LOFR_DO_SHOW)
 			ctx->show_object(obj, base->buf, ctx->show_data);
 	}
 
 	strbuf_setlen(base, baselen);
 	free_tree_buffer(tree);
 }
 
@@ -395,38 +397,33 @@ static void do_traverse(struct traversal_context *ctx)
 void traverse_commit_list(struct rev_info *revs,
 			  show_commit_fn show_commit,
 			  show_object_fn show_object,
 			  void *show_data)
 {
 	struct traversal_context ctx;
 	ctx.revs = revs;
 	ctx.show_commit = show_commit;
 	ctx.show_object = show_object;
 	ctx.show_data = show_data;
-	ctx.filter_fn = NULL;
 	ctx.filter_data = NULL;
 	do_traverse(&ctx);
 }
 
 void traverse_commit_list_filtered(
 	struct list_objects_filter_options *filter_options,
 	struct rev_info *revs,
 	show_commit_fn show_commit,
 	show_object_fn show_object,
 	void *show_data,
 	struct oidset *omitted)
 {
 	struct traversal_context ctx;
-	filter_free_fn filter_free_fn = NULL;
 
 	ctx.revs = revs;
 	ctx.show_object = show_object;
 	ctx.show_commit = show_commit;
 	ctx.show_data = show_data;
-	ctx.filter_fn = NULL;
 
-	ctx.filter_data = list_objects_filter__init(omitted, filter_options,
-						    &ctx.filter_fn, &filter_free_fn);
+	ctx.filter_data = list_objects_filter__init(omitted, filter_options);
 	do_traverse(&ctx);
-	if (ctx.filter_data && filter_free_fn)
-		filter_free_fn(ctx.filter_data);
+	list_objects_filter__free(ctx.filter_data);
 }

diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index c0036f7378..e46ea467bc 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -81,21 +81,21 @@ static int gently_parse_list_objects_filter(
 		filter_options->choice = LOFC_SPARSE_PATH;
 		filter_options->sparse_path_value = strdup(v0);
 		return 0;
 	}
 	/*
 	 * Please update _git_fetch() in git-completion.bash when you
 	 * add new filters
 	 */
 
 	if (errbuf)
-		strbuf_addf(errbuf, "invalid filter-spec '%s'", arg);
+		strbuf_addf(errbuf, _("invalid filter-spec '%s'"), arg);
 
 	memset(filter_options, 0, sizeof(*filter_options));
 	return 1;
 }
 
 int parse_list_objects_filter(struct list_objects_filter_options *filter_options,
 			      const char *arg)
 {
 	struct strbuf buf = STRBUF_INIT;
 	if (gently_parse_list_objects_filter(filter_options, arg, &buf))

Documentation/rev-list-options.txt, contrib/completion/git-completion.bash, list-objects-filter-options.c, list-objects-filter-options.h, list-objects-filter.c, t/t6112-rev-list-filters-objects.sh

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index ddbc1de43f..4fb0c4fbb0 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -730,20 +730,32 @@ specification contained in <path>.
 +
 The form '--filter=tree:<depth>' omits all blobs and trees whose depth
 from the root tree is >= <depth> (minimum depth if an object is located
 at multiple depths in the commits traversed). <depth>=0 will not include
 any trees or blobs unless included explicitly in the command-line (or
 standard input when --stdin is used). <depth>=1 will include only the
 tree and blobs which are referenced directly by a commit reachable from
 <commit> or an explicitly-given object. <depth>=2 is like <depth>=1
 while also including trees and blobs one more level removed from an
 explicitly-given commit or tree.
++
+The form '--filter=combine:<filter1>+<filter2>+...<filterN>' combines
+several filters. Only objects which are accepted by every filter are
+included. Filters are joined by '{plus}' and individual filters are %-encoded
+(i.e. URL-encoded). Besides the '{plus}' and '%' characters, the following
+characters are reserved and also must be encoded:
+`~!@#$^&*()[]{}\;",<>?`+&#39;&#96;+ as well as all characters with ASCII code
+&lt;= `0x20`, which includes space and newline.
++
+Other arbitrary characters can also be encoded. For instance,
+'combine:tree:3+blob:none' and 'combine:tree%3A2+blob%3Anone' are
+equivalent.
 
 --no-filter::
 	Turn off any previous `--filter=` argument.
 
 --filter-print-omitted::
 	Only useful with `--filter=`; prints a list of the objects omitted
 	by the filter.  Object IDs are prefixed with a ``~'' character.
 
 --missing=<missing-action>::
 	A debug option to help with future "partial clone" development.
diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 3eefbabdb1..0fd0a10d0c 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1529,21 +1529,21 @@ _git_difftool ()
 __git_fetch_recurse_submodules="yes on-demand no"
 
 _git_fetch ()
 {
 	case "$cur" in
 	--recurse-submodules=*)
 		__gitcomp "$__git_fetch_recurse_submodules" "" "${cur##--recurse-submodules=}"
 		return
 		;;
 	--filter=*)
-		__gitcomp "blob:none blob:limit= sparse:oid= sparse:path=" "" "${cur##--filter=}"
+		__gitcomp "blob:none blob:limit= sparse:oid= sparse:path= combine: tree:" "" "${cur##--filter=}"
 		return
 		;;
 	--*)
 		__gitcomp_builtin fetch
 		return
 		;;
 	esac
 	__git_complete_remote_or_refspec
 }
 
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index e46ea467bc..d7a1516188 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -1,19 +1,24 @@
 #include "cache.h"
 #include "commit.h"
 #include "config.h"
 #include "revision.h"
 #include "argv-array.h"
 #include "list-objects.h"
 #include "list-objects-filter.h"
 #include "list-objects-filter-options.h"
 
+static int parse_combine_filter(
+	struct list_objects_filter_options *filter_options,
+	const char *arg,
+	struct strbuf *errbuf);
+
 /*
  * Parse value of the argument to the "filter" keyword.
  * On the command line this looks like:
  *       --filter=<arg>
  * and in the pack protocol as:
  *       "filter" SP <arg>
  *
  * The filter keyword will be used by many commands.
  * See Documentation/rev-list-options.txt for allowed values for <arg>.
  *
@@ -31,22 +36,20 @@ static int gently_parse_list_objects_filter(
 
 	if (filter_options->choice) {
 		if (errbuf) {
 			strbuf_addstr(
 				errbuf,
 				_("multiple filter-specs cannot be combined"));
 		}
 		return 1;
 	}
 
-	filter_options->filter_spec = strdup(arg);
-
 	if (!strcmp(arg, "blob:none")) {
 		filter_options->choice = LOFC_BLOB_NONE;
 		return 0;
 
 	} else if (skip_prefix(arg, "blob:limit=", &v0)) {
 		if (git_parse_ulong(v0, &filter_options->blob_limit_value)) {
 			filter_options->choice = LOFC_BLOB_LIMIT;
 			return 0;
 		}
 
@@ -74,37 +77,183 @@ static int gently_parse_list_objects_filter(
 		if (!get_oid_with_context(the_repository, v0, GET_OID_BLOB,
 					  &sparse_oid, &oc))
 			filter_options->sparse_oid_value = oiddup(&sparse_oid);
 		filter_options->choice = LOFC_SPARSE_OID;
 		return 0;
 
 	} else if (skip_prefix(arg, "sparse:path=", &v0)) {
 		filter_options->choice = LOFC_SPARSE_PATH;
 		filter_options->sparse_path_value = strdup(v0);
 		return 0;
+
+	} else if (skip_prefix(arg, "combine:", &v0)) {
+		int sub_parse_res = parse_combine_filter(
+			filter_options, v0, errbuf);
+		if (sub_parse_res)
+			return sub_parse_res;
+		return 0;
+
 	}
 	/*
 	 * Please update _git_fetch() in git-completion.bash when you
 	 * add new filters
 	 */
 
 	if (errbuf)
 		strbuf_addf(errbuf, _("invalid filter-spec '%s'"), arg);
 
 	memset(filter_options, 0, sizeof(*filter_options));
 	return 1;
 }
 
+static int digit_value(int c, struct strbuf *errbuf) {
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	if (c >= 'A' && c <= 'F')
+		return c - 'A' + 10;
+
+	if (!errbuf)
+		return -1;
+
+	strbuf_addf(errbuf, _("error in filter-spec - "));
+	if (c)
+		strbuf_addf(
+			errbuf,
+			_("expect two hex digits after %%, but got: '%c'"),
+			c);
+	else
+		strbuf_addf(
+			errbuf,
+			_("not enough hex digits after %%; expected two"));
+
+	return -1;
+}
+
+static int url_decode(struct strbuf *s, struct strbuf *errbuf) {
+	char *dest = s->buf;
+	char *src = s->buf;
+	size_t new_len;
+
+	while (*src) {
+		int digit_value_0, digit_value_1;
+
+		if (src[0] != '%') {
+			*dest++ = *src++;
+			continue;
+		}
+		src++;
+
+		digit_value_0 = digit_value(*src++, errbuf);
+		if (digit_value_0 < 0)
+			return 1;
+		digit_value_1 = digit_value(*src++, errbuf);
+		if (digit_value_1 < 0)
+			return 1;
+		*dest++ = digit_value_0 * 16 + digit_value_1;
+	}
+	new_len = dest - s->buf;
+	strbuf_remove(s, new_len, s->len - new_len);
+
+	return 0;
+}
+
+static const char *RESERVED_NON_WS = "~`!@#$^&*()[]{}\\;'\",<>?";
+
+static int has_reserved_character(
+	struct strbuf *sub_spec, struct strbuf *errbuf)
+{
+	const char *c = sub_spec->buf;
+	while (*c) {
+		if (*c <= ' ' || strchr(RESERVED_NON_WS, *c))
+			goto found_reserved;
+		c++;
+	}
+
+	return 0;
+
+found_reserved:
+	if (errbuf)
+		strbuf_addf(errbuf,
+			    "must escape char in sub-filter-spec: '%c'",
+			    *c);
+	return 1;
+}
+
+static int parse_combine_filter(
+	struct list_objects_filter_options *filter_options,
+	const char *arg,
+	struct strbuf *errbuf)
+{
+	struct strbuf **sub_specs = strbuf_split_str(arg, '+', 2);
+	int result;
+
+	if (!sub_specs[0]) {
+		if (errbuf)
+			strbuf_addf(errbuf,
+				    _("expected something after combine:"));
+		result = 1;
+		goto cleanup;
+	}
+
+	result = has_reserved_character(sub_specs[0], errbuf);
+	if (result)
+		goto cleanup;
+
+	/*
+	 * Only decode the first sub-filter, since the rest will be decoded on
+	 * the recursive call.
+	 */
+	result = url_decode(sub_specs[0], errbuf);
+	if (result)
+		goto cleanup;
+
+	if (!sub_specs[1]) {
+		/*
+		 * There is only one sub-filter, so we don't need the
+		 * combine: - just parse it as a non-composite filter.
+		 */
+		result = gently_parse_list_objects_filter(
+			filter_options, sub_specs[0]->buf, errbuf);
+		goto cleanup;
+	}
+
+	/* Remove trailing "+" so we can parse it. */
+	assert(sub_specs[0]->buf[sub_specs[0]->len - 1] == '+');
+	strbuf_remove(sub_specs[0], sub_specs[0]->len - 1, 1);
+
+	filter_options->choice = LOFC_COMBINE;
+	filter_options->lhs = xcalloc(1, sizeof(*filter_options->lhs));
+	filter_options->rhs = xcalloc(1, sizeof(*filter_options->rhs));
+
+	result = gently_parse_list_objects_filter(filter_options->lhs,
+						  sub_specs[0]->buf,
+						  errbuf) ||
+		parse_combine_filter(filter_options->rhs,
+				      sub_specs[1]->buf,
+				      errbuf);
+
+cleanup:
+	strbuf_list_free(sub_specs);
+	if (result) {
+		list_objects_filter_release(filter_options);
+		memset(filter_options, 0, sizeof(*filter_options));
+	}
+	return result;
+}
+
 int parse_list_objects_filter(struct list_objects_filter_options *filter_options,
 			      const char *arg)
 {
 	struct strbuf buf = STRBUF_INIT;
+	filter_options->filter_spec = strdup(arg);
 	if (gently_parse_list_objects_filter(filter_options, arg, &buf))
 		die("%s", buf.buf);
 	return 0;
 }
 
 int opt_parse_list_objects_filter(const struct option *opt,
 				  const char *arg, int unset)
 {
 	struct list_objects_filter_options *filter_options = opt->value;
 
@@ -127,23 +276,29 @@ void expand_list_objects_filter_spec(
 	else if (filter->choice == LOFC_TREE_DEPTH)
 		strbuf_addf(expanded_spec, "tree:%lu",
 			    filter->tree_exclude_depth);
 	else
 		strbuf_addstr(expanded_spec, filter->filter_spec);
 }
 
 void list_objects_filter_release(
 	struct list_objects_filter_options *filter_options)
 {
+	if (!filter_options)
+		return;
 	free(filter_options->filter_spec);
 	free(filter_options->sparse_oid_value);
 	free(filter_options->sparse_path_value);
+	list_objects_filter_release(filter_options->lhs);
+	free(filter_options->lhs);
+	list_objects_filter_release(filter_options->rhs);
+	free(filter_options->rhs);
 	memset(filter_options, 0, sizeof(*filter_options));
 }
 
 void partial_clone_register(
 	const char *remote,
 	const struct list_objects_filter_options *filter_options)
 {
 	/*
 	 * Record the name of the partial clone remote in the
 	 * config and in the global variable -- the latter is
@@ -171,14 +326,16 @@ void partial_clone_register(
 }
 
 void partial_clone_get_default_filter_spec(
 	struct list_objects_filter_options *filter_options)
 {
 	/*
 	 * Parse default value, but silently ignore it if it is invalid.
 	 */
 	if (!core_partial_clone_filter_default)
 		return;
+
+	filter_options->filter_spec = strdup(core_partial_clone_filter_default);
 	gently_parse_list_objects_filter(filter_options,
 					 core_partial_clone_filter_default,
 					 NULL);
 }
diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index e3adc78ebf..6c0f0ecd08 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -7,20 +7,21 @@
 /*
  * The list of defined filters for list-objects.
  */
 enum list_objects_filter_choice {
 	LOFC_DISABLED = 0,
 	LOFC_BLOB_NONE,
 	LOFC_BLOB_LIMIT,
 	LOFC_TREE_DEPTH,
 	LOFC_SPARSE_OID,
 	LOFC_SPARSE_PATH,
+	LOFC_COMBINE,
 	LOFC__COUNT /* must be last */
 };
 
 struct list_objects_filter_options {
 	/*
 	 * 'filter_spec' is the raw argument value given on the command line
 	 * or protocol request.  (The part after the "--keyword=".)  For
 	 * commands that launch filtering sub-processes, or for communication
 	 * over the network, don't use this value; use the result of
 	 * expand_list_objects_filter_spec() instead.
@@ -32,28 +33,35 @@ struct list_objects_filter_options {
 	 * the filtering algorithm to use.
 	 */
 	enum list_objects_filter_choice choice;
 
 	/*
 	 * Choice is LOFC_DISABLED because "--no-filter" was requested.
 	 */
 	unsigned int no_filter : 1;
 
 	/*
-	 * Parsed values (fields) from within the filter-spec.  These are
-	 * choice-specific; not all values will be defined for any given
-	 * choice.
+	 * BEGIN choice-specific parsed values from within the filter-spec. Only
+	 * some values will be defined for any given choice.
 	 */
+
 	struct object_id *sparse_oid_value;
 	char *sparse_path_value;
 	unsigned long blob_limit_value;
 	unsigned long tree_exclude_depth;
+
+	/* LOFC_COMBINE values */
+	struct list_objects_filter_options *lhs, *rhs;
+
+	/*
+	 * END choice-specific parsed values.
+	 */
 };
 
 /* Normalized command line arguments */
 #define CL_ARG__FILTER "filter"
 
 int parse_list_objects_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg);
 
 int opt_parse_list_objects_filter(const struct option *opt,
diff --git a/list-objects-filter.c b/list-objects-filter.c
index 8e8616b9b8..b97277a46f 100644
--- a/list-objects-filter.c
+++ b/list-objects-filter.c
@@ -453,34 +453,148 @@ static void filter_sparse_path__init(
 
 	ALLOC_GROW(d->array_frame, d->nr + 1, d->alloc);
 	d->array_frame[d->nr].defval = 0; /* default to include */
 	d->array_frame[d->nr].child_prov_omit = 0;
 
 	ctx->filter_fn = filter_sparse;
 	ctx->free_fn = filter_sparse_free;
 	ctx->data = d;
 }
 
+struct filter_combine_data {
+	/* sub[0] corresponds to lhs, sub[1] to rhs. */
+	struct {
+		struct filter_context ctx;
+		struct oidset seen;
+		struct object_id skip_tree;
+		unsigned is_skipping_tree : 1;
+	} sub[2];
+
+	struct oidset rhs_omits;
+};
+
+static void add_all(struct oidset *dest, struct oidset *src) {
+	struct oidset_iter iter;
+	struct object_id *src_oid;
+
+	oidset_iter_init(src, &iter);
+	while ((src_oid = oidset_iter_next(&iter)) != NULL)
+		oidset_insert(dest, src_oid);
+}
+
+static void filter_combine_free(void *filter_data)
+{
+	struct filter_combine_data *d = filter_data;
+	int i;
+
+	/* Anything omitted by rhs should be added to the overall omits set. */
+	if (d->sub[0].ctx.omits)
+		add_all(d->sub[0].ctx.omits, d->sub[1].ctx.omits);
+
+	for (i = 0; i < 2; i++) {
+		list_objects_filter__release(&d->sub[i].ctx);
+		oidset_clear(&d->sub[i].seen);
+	}
+	oidset_clear(&d->rhs_omits);
+	free(d);
+}
+
+static int should_delegate(enum list_objects_filter_situation filter_situation,
+			   struct object *obj,
+			   struct filter_combine_data *d,
+			   int side)
+{
+	if (!d->sub[side].is_skipping_tree)
+		return 1;
+	if (filter_situation == LOFS_END_TREE &&
+		oideq(&obj->oid, &d->sub[side].skip_tree)) {
+		d->sub[side].is_skipping_tree = 0;
+		return 1;
+	}
+	return 0;
+}
+
+static enum list_objects_filter_result filter_combine(
+	struct repository *r,
+	enum list_objects_filter_situation filter_situation,
+	struct object *obj,
+	const char *pathname,
+	const char *filename,
+	struct filter_context *ctx)
+{
+	struct filter_combine_data *d = ctx->data;
+	enum list_objects_filter_result result[2];
+	enum list_objects_filter_result combined_result = LOFR_ZERO;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		if (oidset_contains(&d->sub[i].seen, &obj->oid) ||
+			!should_delegate(filter_situation, obj, d, i)) {
+			result[i] = LOFR_ZERO;
+			continue;
+		}
+
+		result[i] = d->sub[i].ctx.filter_fn(
+			r, filter_situation, obj, pathname, filename,
+			&d->sub[i].ctx);
+
+		if (result[i] & LOFR_MARK_SEEN)
+			oidset_insert(&d->sub[i].seen, &obj->oid);
+
+		if (result[i] & LOFR_SKIP_TREE) {
+			d->sub[i].is_skipping_tree = 1;
+			d->sub[i].skip_tree = obj->oid;
+		}
+	}
+
+	if ((result[0] & LOFR_DO_SHOW) && (result[1] & LOFR_DO_SHOW))
+		combined_result |= LOFR_DO_SHOW;
+	if (d->sub[0].is_skipping_tree && d->sub[1].is_skipping_tree)
+		combined_result |= LOFR_SKIP_TREE;
+
+	return combined_result;
+}
+
+static void filter_combine__init(
+	struct list_objects_filter_options *filter_options,
+	struct filter_context *ctx)
+{
+	struct filter_combine_data *d = xcalloc(1, sizeof(*d));
+
+	if (ctx->omits)
+		oidset_init(&d->rhs_omits, 16);
+
+	list_objects_filter__init(ctx->omits, filter_options->lhs,
+				  &d->sub[0].ctx);
+	list_objects_filter__init(&d->rhs_omits, filter_options->rhs,
+				  &d->sub[1].ctx);
+
+	ctx->filter_fn = filter_combine;
+	ctx->free_fn = filter_combine_free;
+	ctx->data = d;
+}
+
 typedef void (*filter_init_fn)(
 	struct list_objects_filter_options *filter_options,
 	struct filter_context *ctx);
 
 /*
  * Must match "enum list_objects_filter_choice".
  */
 static filter_init_fn s_filters[] = {
 	NULL,
 	filter_blobs_none__init,
 	filter_blobs_limit__init,
 	filter_trees_depth__init,
 	filter_sparse_oid__init,
 	filter_sparse_path__init,
+	filter_combine__init,
 };
 
 void list_objects_filter__init(
 	struct oidset *omitted,
 	struct list_objects_filter_options *filter_options,
 	struct filter_context *ctx)
 {
 	filter_init_fn init_fn;
 
 	assert((sizeof(s_filters) / sizeof(s_filters[0])) == LOFC__COUNT);
diff --git a/t/t6112-rev-list-filters-objects.sh b/t/t6112-rev-list-filters-objects.sh
index 9c11427719..ddfacb1a1a 100755
--- a/t/t6112-rev-list-filters-objects.sh
+++ b/t/t6112-rev-list-filters-objects.sh
@@ -284,21 +284,33 @@ test_expect_success 'verify tree:0 includes trees in "filtered" output' '
 # Make sure tree:0 does not iterate through any trees.
 
 test_expect_success 'verify skipping tree iteration when not collecting omits' '
 	GIT_TRACE=1 git -C r3 rev-list \
 		--objects --filter=tree:0 HEAD 2>filter_trace &&
 	grep "Skipping contents of tree [.][.][.]" filter_trace >actual &&
 	# One line for each commit traversed.
 	test_line_count = 2 actual &&
 
 	# Make sure no other trees were considered besides the root.
-	! grep "Skipping contents of tree [^.]" filter_trace
+	! grep "Skipping contents of tree [^.]" filter_trace &&
+
+	# Try this again with "combine:". If both sub-filters are skipping
+	# trees, the composite filter should also skip trees. This is not
+	# important unless the user does combine:tree:X+tree:Y or another filter
+	# besides "tree:" is implemented in the future which can skip trees.
+	GIT_TRACE=1 git -C r3 rev-list \
+		--objects --filter=combine:tree:1+tree:3 HEAD 2>filter_trace &&
+
+	# Only skip the dir1/ tree, which is shared between the two commits.
+	grep "Skipping contents of tree " filter_trace >actual &&
+	test_write_lines "Skipping contents of tree dir1/..." >expected &&
+	test_cmp expected actual
 '
 
 # Test tree:# filters.
 
 expect_has () {
 	commit=$1 &&
 	name=$2 &&
 
 	hash=$(git -C r3 rev-parse $commit:$name) &&
 	grep "^$hash $name$" actual
@@ -336,20 +348,134 @@ test_expect_success 'verify tree:3 includes everything expected' '
 	expect_has HEAD dir1/sparse1 &&
 	expect_has HEAD dir1/sparse2 &&
 	expect_has HEAD pattern &&
 	expect_has HEAD sparse1 &&
 	expect_has HEAD sparse2 &&
 
 	# There are also 2 commit objects
 	test_line_count = 10 actual
 '
 
+test_expect_success 'combine:... for a simple combination' '
+	git -C r3 rev-list --objects --filter=combine:tree:2+blob:none HEAD \
+		>actual &&
+
+	expect_has HEAD "" &&
+	expect_has HEAD~1 "" &&
+	expect_has HEAD dir1 &&
+
+	# There are also 2 commit objects
+	test_line_count = 5 actual
+'
+
+test_expect_success 'combine:... with URL encoding' '
+	git -C r3 rev-list --objects \
+		--filter=combine:tree%3a2+blob:%6Eon%65 HEAD >actual &&
+
+	expect_has HEAD "" &&
+	expect_has HEAD~1 "" &&
+	expect_has HEAD dir1 &&
+
+	# There are also 2 commit objects
+	test_line_count = 5 actual
+'
+
+expect_invalid_filter_spec () {
+	spec="$1" &&
+	err="$2" &&
+
+	test_must_fail git -C r3 rev-list --objects --filter="$spec" HEAD \
+		>actual 2>actual_stderr &&
+	test_must_be_empty actual &&
+	test_i18ngrep "$err" actual_stderr
+}
+
+test_expect_success 'combine:... while URL-encoding things that should not be' '
+	expect_invalid_filter_spec combine%3Atree:2+blob:none \
+		"invalid filter-spec"
+'
+
+test_expect_success 'combine: with nothing after the :' '
+	expect_invalid_filter_spec combine: "expected something after combine:"
+'
+
+test_expect_success 'parse error in first sub-filter in combine:' '
+	expect_invalid_filter_spec combine:tree:asdf+blob:none \
+		"expected .tree:<depth>."
+'
+
+test_expect_success 'combine:... with invalid URL-encoded sequences' '
+	expect_invalid_filter_spec combine:tree:2+blob:non%a \
+		"error in filter-spec - not enough hex digits after %" &&
+	# Edge cases for non-hex chars: "Gg/:"
+	expect_invalid_filter_spec combine:tree:2+blob%G5none \
+		"error in filter-spec - expect two hex digits .*: .G." &&
+	expect_invalid_filter_spec combine:tree:2+blob%g5none \
+		"error in filter-spec - expect two hex digits .*: .g." &&
+	expect_invalid_filter_spec combine:tree:2+blob%5/none \
+		"error in filter-spec - expect two hex digits .*: ./." &&
+	expect_invalid_filter_spec combine:%:5tree:2+blob:none \
+		"error in filter-spec - expect two hex digits .*: .:."
+'
+
+test_expect_success 'combine:... with non-encoded reserved chars' '
+	expect_invalid_filter_spec combine:tree:2+sparse:@xyz \
+		"must escape char in sub-filter-spec: .@." &&
+	expect_invalid_filter_spec combine:tree:2+sparse:\` \
+		"must escape char in sub-filter-spec: .\`." &&
+	expect_invalid_filter_spec combine:tree:2+sparse:~abc \
+		"must escape char in sub-filter-spec: .\~."
+'
+
+test_expect_success 'validate err msg for "combine:<valid-filter>+"' '
+	expect_invalid_filter_spec combine:tree:2+ "expected .tree:<depth>."
+'
+
+test_expect_success 'combine:... with edge-case hex digits: Ff Aa 0 9' '
+	git -C r3 rev-list --objects --filter="combine:tree:2+bl%6Fb:n%6fne" \
+		HEAD >actual &&
+	test_line_count = 5 actual &&
+	git -C r3 rev-list --objects --filter="combine:tree%3A2+blob%3anone" \
+		HEAD >actual &&
+	test_line_count = 5 actual &&
+	git -C r3 rev-list --objects --filter="combine:tree:%30" HEAD >actual &&
+	test_line_count = 2 actual &&
+	git -C r3 rev-list --objects --filter="combine:tree:%39+blob:none" \
+		HEAD >actual &&
+	test_line_count = 5 actual
+'
+
+test_expect_success 'combine:... with more than two sub-filters' '
+	git -C r3 rev-list --objects \
+		--filter=combine:tree:3+blob:limit=40+sparse:path=../pattern1 \
+		HEAD >actual &&
+
+	expect_has HEAD "" &&
+	expect_has HEAD~1 "" &&
+	expect_has HEAD dir1 &&
+	expect_has HEAD dir1/sparse1 &&
+	expect_has HEAD dir1/sparse2 &&
+
+	# Should also have 2 commits
+	test_line_count = 7 actual &&
+
+	# Try again, this time making sure the last sub-filter is only
+	# URL-decoded once.
+	cp pattern1 pattern1+renamed% &&
+	cp actual expect &&
+
+	git -C r3 rev-list --objects \
+		--filter=combine:tree:3+blob:limit=40+sparse:path=../pattern1%2brenamed%25 \
+		HEAD >actual &&
+	test_cmp expect actual
+'
+
 # Test provisional omit collection logic with a repo that has objects appearing
 # at multiple depths - first deeper than the filter's threshold, then shallow.
 
 test_expect_success 'setup r4' '
 	git init r4 &&
 
 	echo foo > r4/foo &&
 	mkdir r4/subdir &&
 	echo bar > r4/subdir/bar &&
 
@@ -379,20 +505,51 @@ test_expect_success 'test tree:# filter provisional omit for blob and tree' '
 
 test_expect_success 'verify skipping tree iteration when collecting omits' '
 	GIT_TRACE=1 git -C r4 rev-list --filter-print-omitted \
 		--objects --filter=tree:0 HEAD 2>filter_trace &&
 	grep "^Skipping contents of tree " filter_trace >actual &&
 
 	echo "Skipping contents of tree subdir/..." >expect &&
 	test_cmp expect actual
 '
 
+test_expect_success 'setup r5' '
+	git init r5 &&
+	mkdir -p r5/subdir &&
+
+	echo 1     >r5/short-root          &&
+	echo 12345 >r5/long-root           &&
+	echo a     >r5/subdir/short-subdir &&
+	echo abcde >r5/subdir/long-subdir  &&
+
+	git -C r5 add short-root long-root subdir &&
+	git -C r5 commit -m "commit msg"
+'
+
+test_expect_success 'verify collecting omits in combined: filter' '
+	# Note that this test guards against the naive implementation of simply
+	# giving both filters the same "omits" set and expecting it to
+	# automatically merge them.
+	git -C r5 rev-list --objects --quiet --filter-print-omitted \
+		--filter=combine:tree:2+blob:limit=3 HEAD >actual &&
+
+	# Expect 0 trees/commits, 3 blobs omitted (all blobs except short-root)
+	omitted_1=$(echo 12345 | git hash-object --stdin) &&
+	omitted_2=$(echo a     | git hash-object --stdin) &&
+	omitted_3=$(echo abcde | git hash-object --stdin) &&
+
+	grep ~$omitted_1 actual &&
+	grep ~$omitted_2 actual &&
+	grep ~$omitted_3 actual &&
+	test_line_count = 3 actual
+'
+
 # Test tree:<depth> where a tree is iterated to twice - once where a subentry is
 # too deep to be included, and again where the blob inside it is shallow enough
 # to be included. This makes sure we don't use LOFR_MARK_SEEN incorrectly (we
 # can't use it because a tree can be iterated over again at a lower depth).
 
 test_expect_success 'tree:<depth> where we iterate over tree at two levels' '
 	git init r5 &&
 
 	mkdir -p r5/a/subdir/b &&
 	echo foo > r5/a/subdir/b/foo &&

list-objects-filter-options.c, t/t6112-rev-list-filters-objects.sh, url.c, url.h

diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index ed02c88eb6..0f135602a7 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -1,19 +1,20 @@
 #include "cache.h"
 #include "commit.h"
 #include "config.h"
 #include "revision.h"
 #include "argv-array.h"
 #include "list-objects.h"
 #include "list-objects-filter.h"
 #include "list-objects-filter-options.h"
 #include "trace.h"
+#include "url.h"
 
 static int parse_combine_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg,
 	struct strbuf *errbuf);
 
 /*
  * Parse value of the argument to the "filter" keyword.
  * On the command line this looks like:
  *       --filter=<arg>
@@ -84,54 +85,20 @@ static int gently_parse_list_objects_filter(
 	 * Please update _git_fetch() in git-completion.bash when you
 	 * add new filters
 	 */
 
 	strbuf_addf(errbuf, "invalid filter-spec '%s'", arg);
 
 	memset(filter_options, 0, sizeof(*filter_options));
 	return 1;
 }
 
-static int url_decode(struct strbuf *s, struct strbuf *errbuf)
-{
-	char *dest = s->buf;
-	char *src = s->buf;
-	size_t new_len;
-
-	while (*src) {
-		if (src[0] != '%') {
-			*dest++ = *src++;
-			continue;
-		}
-
-		if (hex_to_bytes((unsigned char *)dest, src + 1, 1)) {
-			strbuf_addstr(errbuf,
-				      "error in filter-spec - "
-				      "invalid hex sequence after %");
-			return 1;
-		}
-
-		if (!*dest) {
-			strbuf_addstr(errbuf,
-				      "error in filter-spec - unexpected %00");
-			return 1;
-		}
-
-		src += 3;
-		dest++;
-	}
-	new_len = dest - s->buf;
-	strbuf_remove(s, new_len, s->len - new_len);
-
-	return 0;
-}
-
 static const char *RESERVED_NON_WS = "~`!@#$^&*()[]{}\\;'\",<>?";
 
 static int has_reserved_character(
 	struct strbuf *sub_spec, struct strbuf *errbuf)
 {
 	const char *c = sub_spec->buf;
 	while (*c) {
 		if (*c <= ' ' || strchr(RESERVED_NON_WS, *c)) {
 			strbuf_addf(errbuf,
 				    "must escape char in sub-filter-spec: '%c'",
@@ -147,56 +114,57 @@ static int has_reserved_character(
 static int parse_combine_subfilter(
 	struct list_objects_filter_options *filter_options,
 	struct strbuf *subspec,
 	struct strbuf *errbuf)
 {
 	size_t new_index = filter_options->sub_nr;
 
 	ALLOC_GROW_BY(filter_options->sub, filter_options->sub_nr, 1,
 		      filter_options->sub_alloc);
 
-	return has_reserved_character(subspec, errbuf) ||
-		url_decode(subspec, errbuf) ||
-		gently_parse_list_objects_filter(
-			&filter_options->sub[new_index], subspec->buf, errbuf);
+	decoded = url_percent_decode(subspec->buf);
+
+	result = gently_parse_list_objects_filter(
+		&filter_options->sub[new_index], decoded, errbuf);
+
+	free(decoded);
+	return result;
 }
 
 static int parse_combine_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg,
 	struct strbuf *errbuf)
 {
 	struct strbuf **subspecs = strbuf_split_str(arg, '+', 0);
 	size_t sub;
-	int result;
+	int result = 0;
 
 	if (!subspecs[0]) {
 		strbuf_addf(errbuf,
 			    _("expected something after combine:"));
 		result = 1;
 		goto cleanup;
 	}
 
-	for (sub = 0; subspecs[sub]; sub++) {
+	for (sub = 0; subspecs[sub] && !result; sub++) {
 		if (subspecs[sub + 1]) {
 			/*
 			 * This is not the last subspec. Remove trailing "+" so
 			 * we can parse it.
 			 */
 			size_t last = subspecs[sub]->len - 1;
 			assert(subspecs[sub]->buf[last] == '+');
 			strbuf_remove(subspecs[sub], last, 1);
 		}
 		result = parse_combine_subfilter(
 			filter_options, subspecs[sub], errbuf);
-		if (result)
-			goto cleanup;
 	}
 
 	filter_options->choice = LOFC_COMBINE;
 
 cleanup:
 	strbuf_list_free(subspecs);
 	if (result) {
 		list_objects_filter_release(filter_options);
 		memset(filter_options, 0, sizeof(*filter_options));
 	}
diff --git a/t/t6112-rev-list-filters-objects.sh b/t/t6112-rev-list-filters-objects.sh
index 7fb5e50cde..e1bf3ed038 100755
--- a/t/t6112-rev-list-filters-objects.sh
+++ b/t/t6112-rev-list-filters-objects.sh
@@ -405,32 +405,20 @@ test_expect_success 'combine:... while URL-encoding things that should not be' '
 
 test_expect_success 'combine: with nothing after the :' '
 	expect_invalid_filter_spec combine: "expected something after combine:"
 '
 
 test_expect_success 'parse error in first sub-filter in combine:' '
 	expect_invalid_filter_spec combine:tree:asdf+blob:none \
 		"expected .tree:<depth>."
 '
 
-test_expect_success 'combine:... with invalid URL-encoded sequences' '
-	# Not enough hex chars
-	expect_invalid_filter_spec combine:tree:2+blob:non%a \
-		"error in filter-spec - invalid hex sequence after %" &&
-	# Non-hex digit after %
-	expect_invalid_filter_spec combine:tree:2+blob%G5none \
-		"error in filter-spec - invalid hex sequence after %" &&
-	# Null byte encoded by %
-	expect_invalid_filter_spec combine:tree:2+blob%00none \
-		"error in filter-spec - unexpected %00"
-'
-
 test_expect_success 'combine:... with non-encoded reserved chars' '
 	expect_invalid_filter_spec combine:tree:2+sparse:@xyz \
 		"must escape char in sub-filter-spec: .@." &&
 	expect_invalid_filter_spec combine:tree:2+sparse:\` \
 		"must escape char in sub-filter-spec: .\`." &&
 	expect_invalid_filter_spec combine:tree:2+sparse:~abc \
 		"must escape char in sub-filter-spec: .\~."
 '
 
 test_expect_success 'validate err msg for "combine:<valid-filter>+"' '
diff --git a/url.c b/url.c
index 25576c390b..bdede647bc 100644
--- a/url.c
+++ b/url.c
@@ -79,20 +79,26 @@ char *url_decode_mem(const char *url, int len)
 
 	/* Skip protocol part if present */
 	if (colon && url < colon) {
 		strbuf_add(&out, url, colon - url);
 		len -= colon - url;
 		url = colon;
 	}
 	return url_decode_internal(&url, len, NULL, &out, 0);
 }
 
+char *url_percent_decode(const char *encoded)
+{
+	struct strbuf out = STRBUF_INIT;
+	return url_decode_internal(&encoded, strlen(encoded), NULL, &out, 0);
+}
+
 char *url_decode_parameter_name(const char **query)
 {
 	struct strbuf out = STRBUF_INIT;
 	return url_decode_internal(query, -1, "&=", &out, 1);
 }
 
 char *url_decode_parameter_value(const char **query)
 {
 	struct strbuf out = STRBUF_INIT;
 	return url_decode_internal(query, -1, "&", &out, 1);
diff --git a/url.h b/url.h
index 00b7d58c33..2a27c34277 100644
--- a/url.h
+++ b/url.h
@@ -1,16 +1,24 @@
 #ifndef URL_H
 #define URL_H
 
 struct strbuf;
 
 int is_url(const char *url);
 int is_urlschemechar(int first_flag, int ch);
 char *url_decode(const char *url);
 char *url_decode_mem(const char *url, int len);
+
+/*
+ * Similar to the url_decode_{,mem} methods above, but doesn't assume there
+ * is a scheme followed by a : at the start of the string. Instead, %-sequences
+ * before any : are also parsed.
+ */
+char *url_percent_decode(const char *encoded);
+
 char *url_decode_parameter_name(const char **query);
 char *url_decode_parameter_value(const char **query);
 
 void end_url_with_slash(struct strbuf *buf, const char *url);
 void str_end_url_with_slash(const char *url, char **dest);
 
 #endif /* URL_H */

diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 0f135602a7..6b206dc58b 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -110,28 +110,31 @@ static int has_reserved_character(
 
 	return 0;
 }
 
 static int parse_combine_subfilter(
 	struct list_objects_filter_options *filter_options,
 	struct strbuf *subspec,
 	struct strbuf *errbuf)
 {
 	size_t new_index = filter_options->sub_nr;
+	char *decoded;
+	int result;
 
 	ALLOC_GROW_BY(filter_options->sub, filter_options->sub_nr, 1,
 		      filter_options->sub_alloc);
 
 	decoded = url_percent_decode(subspec->buf);
 
-	result = gently_parse_list_objects_filter(
-		&filter_options->sub[new_index], decoded, errbuf);
+	result = has_reserved_character(subspec, errbuf) ||
+		gently_parse_list_objects_filter(
+			&filter_options->sub[new_index], decoded, errbuf);
 
 	free(decoded);
 	return result;
 }
 
 static int parse_combine_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg,
 	struct strbuf *errbuf)
 {

> > strbuf_addstr_urlencode will either escape or not escape all rfc3986
> > reserved characters, and that set includes both : and +. The former
> > should not require escaping since it's a common character in filter
> > specs, and I would like the hand-encoded combine specs to be relatively
> > easy to type and read. The + must be escaped since it is used as part of
> > the combine:... syntax to delimit sub filters. So
> > strbuf_addstr_url_encode would have to be more customizable to make it
> > work for this context. I'd like to add a parameterizable should_escape
> > predicate (iow function pointer) which strbuf_addstr_urlencode accepts.
> > I actually think this will be more readable than the current strbuf API.
> 
> That makes some sense, and I agree that readability is a good goal. Do
> we not need to be escaping colons in other URLs? Or are the strings
> you're generating not true by-the-book URLs? I'm just wondering if we
> could take this opportunity to improve the URLs we output elsewhere,
> too.

The strings I'm generating are not URLs. Also, in http.c, we have to use : to
delimit a username and password:

	strbuf_addstr_urlencode(&s, proxy_auth.username, 1);
	strbuf_addch(&s, ':');
	strbuf_addstr_urlencode(&s, proxy_auth.password, 1);

I think this is dictated by libcurl and is not flexible.

credential-store.c, http.c, list-objects-filter-options.c, strbuf.c, strbuf.h

diff --git a/credential-store.c b/credential-store.c
index ac295420dd..c010497cb2 100644
--- a/credential-store.c
+++ b/credential-store.c
@@ -65,29 +65,30 @@ static void rewrite_credential_file(const char *fn, struct credential *c,
 	parse_credential_file(fn, c, NULL, print_line);
 	if (commit_lock_file(&credential_lock) < 0)
 		die_errno("unable to write credential store");
 }
 
 static void store_credential_file(const char *fn, struct credential *c)
 {
 	struct strbuf buf = STRBUF_INIT;
 
 	strbuf_addf(&buf, "%s://", c->protocol);
-	strbuf_addstr_urlencode(&buf, c->username, 1);
+	strbuf_addstr_urlencode(&buf, c->username, is_rfc3986_unreserved);
 	strbuf_addch(&buf, ':');
-	strbuf_addstr_urlencode(&buf, c->password, 1);
+	strbuf_addstr_urlencode(&buf, c->password, is_rfc3986_unreserved);
 	strbuf_addch(&buf, '@');
 	if (c->host)
-		strbuf_addstr_urlencode(&buf, c->host, 1);
+		strbuf_addstr_urlencode(&buf, c->host, is_rfc3986_unreserved);
 	if (c->path) {
 		strbuf_addch(&buf, '/');
-		strbuf_addstr_urlencode(&buf, c->path, 0);
+		strbuf_addstr_urlencode(&buf, c->path,
+					is_rfc3986_reserved_or_unreserved);
 	}
 
 	rewrite_credential_file(fn, c, &buf);
 	strbuf_release(&buf);
 }
 
 static void store_credential(const struct string_list *fns, struct credential *c)
 {
 	struct string_list_item *fn;
 
diff --git a/http.c b/http.c
index 27aa0a3192..938b9e55af 100644
--- a/http.c
+++ b/http.c
@@ -506,23 +506,25 @@ static void var_override(const char **var, char *value)
 static void set_proxyauth_name_password(CURL *result)
 {
 #if LIBCURL_VERSION_NUM >= 0x071301
 		curl_easy_setopt(result, CURLOPT_PROXYUSERNAME,
 			proxy_auth.username);
 		curl_easy_setopt(result, CURLOPT_PROXYPASSWORD,
 			proxy_auth.password);
 #else
 		struct strbuf s = STRBUF_INIT;
 
-		strbuf_addstr_urlencode(&s, proxy_auth.username, 1);
+		strbuf_addstr_urlencode(&s, proxy_auth.username,
+					is_rfc3986_unreserved);
 		strbuf_addch(&s, ':');
-		strbuf_addstr_urlencode(&s, proxy_auth.password, 1);
+		strbuf_addstr_urlencode(&s, proxy_auth.password,
+					is_rfc3986_unreserved);
 		curl_proxyuserpwd = strbuf_detach(&s, NULL);
 		curl_easy_setopt(result, CURLOPT_PROXYUSERPWD, curl_proxyuserpwd);
 #endif
 }
 
 static void init_curl_proxy_auth(CURL *result)
 {
 	if (proxy_auth.username) {
 		if (!proxy_auth.password)
 			credential_fill(&proxy_auth);
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 6b206dc58b..9a5677c2c8 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -167,30 +167,25 @@ static int parse_combine_filter(
 
 cleanup:
 	strbuf_list_free(subspecs);
 	if (result) {
 		list_objects_filter_release(filter_options);
 		memset(filter_options, 0, sizeof(*filter_options));
 	}
 	return result;
 }
 
-static void add_url_encoded(struct strbuf *dest, const char *s)
+static int allow_unencoded(char ch)
 {
-	while (*s) {
-		if (*s <= ' ' || strchr(RESERVED_NON_WS, *s) ||
-			*s == '%' || *s == '+')
-			strbuf_addf(dest, "%%%02X", (int)*s);
-		else
-			strbuf_addf(dest, "%c", *s);
-		s++;
-	}
+	if (ch <= ' ' || ch == '%' || ch == '+')
+		return 0;
+	return !strchr(RESERVED_NON_WS, ch);
 }
 
 /*
  * Changes filter_options into an equivalent LOFC_COMBINE filter options
  * instance. Does not do anything if filter_options is already LOFC_COMBINE.
  */
 static void transform_to_combine_type(
 	struct list_objects_filter_options *filter_options)
 {
 	assert(filter_options->choice);
@@ -202,22 +197,23 @@ static void transform_to_combine_type(
 			xcalloc(initial_sub_alloc, sizeof(*sub_array));
 		sub_array[0] = *filter_options;
 		memset(filter_options, 0, sizeof(*filter_options));
 		filter_options->sub = sub_array;
 		filter_options->sub_alloc = initial_sub_alloc;
 	}
 	filter_options->sub_nr = 1;
 	filter_options->choice = LOFC_COMBINE;
 	strbuf_init(&filter_options->filter_spec, 0);
 	strbuf_addstr(&filter_options->filter_spec, "combine:");
-	add_url_encoded(&filter_options->filter_spec,
-			filter_options->sub[0].filter_spec.buf);
+	strbuf_addstr_urlencode(&filter_options->filter_spec,
+				filter_options->sub[0].filter_spec.buf,
+				allow_unencoded);
 	/*
 	 * We don't need the filter_spec strings for subfilter specs, only the
 	 * top level.
 	 */
 	strbuf_release(&filter_options->sub[0].filter_spec);
 }
 
 void list_objects_filter_die_if_populated(
 	struct list_objects_filter_options *filter_options)
 {
@@ -239,21 +235,22 @@ void parse_list_objects_filter(
 		parse_error = gently_parse_list_objects_filter(
 			filter_options, arg, &errbuf);
 	} else {
 		/*
 		 * Make filter_options an LOFC_COMBINE spec so we can trivially
 		 * add subspecs to it.
 		 */
 		transform_to_combine_type(filter_options);
 
 		strbuf_addstr(&filter_options->filter_spec, "+");
-		add_url_encoded(&filter_options->filter_spec, arg);
+		strbuf_addstr_urlencode(&filter_options->filter_spec, arg,
+					allow_unencoded);
 		trace_printf("Generated composite filter-spec: %s\n",
 			     filter_options->filter_spec.buf);
 		ALLOC_GROW_BY(filter_options->sub, filter_options->sub_nr, 1,
 			      filter_options->sub_alloc);
 
 		parse_error = gently_parse_list_objects_filter(
 			&filter_options->sub[filter_options->sub_nr - 1], arg,
 			&errbuf);
 	}
 	if (parse_error)
diff --git a/strbuf.c b/strbuf.c
index 0e18b259ce..60ab5144f2 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -767,55 +767,56 @@ void strbuf_addstr_xml_quoted(struct strbuf *buf, const char *s)
 		case '&':
 			strbuf_addstr(buf, "&amp;");
 			break;
 		case 0:
 			return;
 		}
 		s++;
 	}
 }
 
-static int is_rfc3986_reserved(char ch)
+int is_rfc3986_reserved_or_unreserved(char ch)
 {
+	if (is_rfc3986_unreserved(ch))
+		return 1;
 	switch (ch) {
 		case '!': case '*': case '\'': case '(': case ')': case ';':
 		case ':': case '@': case '&': case '=': case '+': case '$':
 		case ',': case '/': case '?': case '#': case '[': case ']':
 			return 1;
 	}
 	return 0;
 }
 
-static int is_rfc3986_unreserved(char ch)
+int is_rfc3986_unreserved(char ch)
 {
 	return isalnum(ch) ||
 		ch == '-' || ch == '_' || ch == '.' || ch == '~';
 }
 
 static void strbuf_add_urlencode(struct strbuf *sb, const char *s, size_t len,
-				 int reserved)
+				 char_predicate allow_unencoded_fn)
 {
 	strbuf_grow(sb, len);
 	while (len--) {
 		char ch = *s++;
-		if (is_rfc3986_unreserved(ch) ||
-		    (!reserved && is_rfc3986_reserved(ch)))
+		if (allow_unencoded_fn(ch))
 			strbuf_addch(sb, ch);
 		else
 			strbuf_addf(sb, "%%%02x", (unsigned char)ch);
 	}
 }
 
 void strbuf_addstr_urlencode(struct strbuf *sb, const char *s,
-			     int reserved)
+			     char_predicate allow_unencoded_fn)
 {
-	strbuf_add_urlencode(sb, s, strlen(s), reserved);
+	strbuf_add_urlencode(sb, s, strlen(s), allow_unencoded_fn);
 }
 
 void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes)
 {
 	if (bytes > 1 << 30) {
 		strbuf_addf(buf, "%u.%2.2u GiB",
 			    (unsigned)(bytes >> 30),
 			    (unsigned)(bytes & ((1 << 30) - 1)) / 10737419);
 	} else if (bytes > 1 << 20) {
 		unsigned x = bytes + 5243;  /* for rounding */
diff --git a/strbuf.h b/strbuf.h
index c8d98dfb95..346d722492 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -659,22 +659,27 @@ void strbuf_branchname(struct strbuf *sb, const char *name,
 		       unsigned allowed);
 
 /*
  * Like strbuf_branchname() above, but confirm that the result is
  * syntactically valid to be used as a local branch name in refs/heads/.
  *
  * The return value is "0" if the result is valid, and "-1" otherwise.
  */
 int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
 
+typedef int (*char_predicate)(char ch);
+
+int is_rfc3986_unreserved(char ch);
+int is_rfc3986_reserved_or_unreserved(char ch);
+
 void strbuf_addstr_urlencode(struct strbuf *sb, const char *name,
-			     int reserved);
+			     char_predicate allow_unencoded_fn);
 
 __attribute__((format (printf,1,2)))
 int printf_ln(const char *fmt, ...);
 __attribute__((format (printf,2,3)))
 int fprintf_ln(FILE *fp, const char *fmt, ...);
 
 char *xstrdup_tolower(const char *);
 char *xstrdup_toupper(const char *);
 
 /**

diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index d7a1516188..647b2b220e 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -27,28 +27,22 @@ static int parse_combine_filter(
  * expand_list_objects_filter_spec() first).  We also "intern" the arg for the
  * convenience of the current command.
  */
 static int gently_parse_list_objects_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg,
 	struct strbuf *errbuf)
 {
 	const char *v0;
 
-	if (filter_options->choice) {
-		if (errbuf) {
-			strbuf_addstr(
-				errbuf,
-				_("multiple filter-specs cannot be combined"));
-		}
-		return 1;
-	}
+	if (filter_options->choice)
+		BUG("filter_options already populated");
 
 	if (!strcmp(arg, "blob:none")) {
 		filter_options->choice = LOFC_BLOB_NONE;
 		return 0;
 
 	} else if (skip_prefix(arg, "blob:limit=", &v0)) {
 		if (git_parse_ulong(v0, &filter_options->blob_limit_value)) {
 			filter_options->choice = LOFC_BLOB_LIMIT;
 			return 0;
 		}
@@ -239,20 +233,22 @@ cleanup:
 		list_objects_filter_release(filter_options);
 		memset(filter_options, 0, sizeof(*filter_options));
 	}
 	return result;
 }
 
 int parse_list_objects_filter(struct list_objects_filter_options *filter_options,
 			      const char *arg)
 {
 	struct strbuf buf = STRBUF_INIT;
+	if (filter_options->choice)
+		die(_("multiple filter-specs cannot be combined"));
 	filter_options->filter_spec = strdup(arg);
 	if (gently_parse_list_objects_filter(filter_options, arg, &buf))
 		die("%s", buf.buf);
 	return 0;
 }
 
 int opt_parse_list_objects_filter(const struct option *opt,
 				  const char *arg, int unset)
 {
 	struct list_objects_filter_options *filter_options = opt->value;

Documentation/rev-list-options.txt, builtin/fetch-pack.c, builtin/rev-list.c, fetch-pack.c, list-objects-filter-options.c, list-objects-filter-options.h, t/t5616-partial-clone.sh, t/t6112-rev-list-filters-objects.sh, transport.c, upload-pack.c

diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index 4fb0c4fbb0..2be5f3a6d1 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -731,27 +731,29 @@ specification contained in <path>.
 The form '--filter=tree:<depth>' omits all blobs and trees whose depth
 from the root tree is >= <depth> (minimum depth if an object is located
 at multiple depths in the commits traversed). <depth>=0 will not include
 any trees or blobs unless included explicitly in the command-line (or
 standard input when --stdin is used). <depth>=1 will include only the
 tree and blobs which are referenced directly by a commit reachable from
 <commit> or an explicitly-given object. <depth>=2 is like <depth>=1
 while also including trees and blobs one more level removed from an
 explicitly-given commit or tree.
 +
-The form '--filter=combine:<filter1>+<filter2>+...<filterN>' combines
-several filters. Only objects which are accepted by every filter are
-included. Filters are joined by '{plus}' and individual filters are %-encoded
-(i.e. URL-encoded). Besides the '{plus}' and '%' characters, the following
-characters are reserved and also must be encoded:
-`~!@#$^&*()[]{}\;",<>?`+&#39;&#96;+ as well as all characters with ASCII code
-&lt;= `0x20`, which includes space and newline.
+Multiple '--filter=' flags can be specified to combine filters. Only
+objects which are accepted by every filter are included.
++
+The form '--filter=combine:<filter1>+<filter2>+...<filterN>' can also be
+used to combine filters. Filters are joined by '{plus}' and individual
+filters are %-encoded (i.e. URL-encoded). Besides the '{plus}' and '%'
+characters, the following characters are reserved and also must be
+encoded: `~!@#$^&*()[]{}\;",<>?`+&#39;&#96;+ as well as all characters
+with ASCII code &lt;= `0x20`, which includes space and newline.
 +
 Other arbitrary characters can also be encoded. For instance,
 'combine:tree:3+blob:none' and 'combine:tree%3A2+blob%3Anone' are
 equivalent.
 
 --no-filter::
 	Turn off any previous `--filter=` argument.
 
 --filter-print-omitted::
 	Only useful with `--filter=`; prints a list of the objects omitted
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index dc1485c8aa..cadcb2b915 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -151,21 +151,24 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 		}
 		if (!strcmp("--from-promisor", arg)) {
 			args.from_promisor = 1;
 			continue;
 		}
 		if (!strcmp("--no-dependents", arg)) {
 			args.no_dependents = 1;
 			continue;
 		}
 		if (skip_prefix(arg, ("--" CL_ARG__FILTER "="), &arg)) {
-			parse_list_objects_filter(&args.filter_options, arg);
+			parse_list_objects_filter(
+				&args.filter_options,
+				arg,
+				/*allow_implicit_combine=*/1);
 			continue;
 		}
 		if (!strcmp(arg, ("--no-" CL_ARG__FILTER))) {
 			list_objects_filter_set_no_filter(&args.filter_options);
 			continue;
 		}
 		usage(fetch_pack_usage);
 	}
 	if (deepen_not.nr)
 		args.deepen_not = &deepen_not;
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index 9f31837d30..e584e7d1ac 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -454,21 +454,24 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
 		if (!strcmp(arg, "--test-bitmap")) {
 			test_bitmap_walk(&revs);
 			return 0;
 		}
 		if (skip_prefix(arg, "--progress=", &arg)) {
 			show_progress = arg;
 			continue;
 		}
 
 		if (skip_prefix(arg, ("--" CL_ARG__FILTER "="), &arg)) {
-			parse_list_objects_filter(&filter_options, arg);
+			parse_list_objects_filter(
+				&filter_options,
+				arg,
+				/*allow_implicit_combine=*/1);
 			if (filter_options.choice && !revs.blob_objects)
 				die(_("object filtering requires --objects"));
 			if (filter_options.choice == LOFC_SPARSE_OID &&
 			    !filter_options.sparse_oid_value)
 				die(_("invalid sparse value '%s'"),
 				    filter_options.filter_spec);
 			continue;
 		}
 		if (!strcmp(arg, ("--no-" CL_ARG__FILTER))) {
 			list_objects_filter_set_no_filter(&filter_options);
diff --git a/fetch-pack.c b/fetch-pack.c
index 3f24d0c8a6..c58fd9148a 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -1661,21 +1661,24 @@ struct ref *fetch_pack(struct fetch_pack_args *args,
 		/*
 		 * The protocol does not support requesting that only the
 		 * wanted objects be sent, so approximate this by setting a
 		 * "blob:none" filter if no filter is already set. This works
 		 * for all object types: note that wanted blobs will still be
 		 * sent because they are directly specified as a "want".
 		 *
 		 * NEEDSWORK: Add an option in the protocol to request that
 		 * only the wanted objects be sent, and implement it.
 		 */
-		parse_list_objects_filter(&args->filter_options, "blob:none");
+		parse_list_objects_filter(
+			&args->filter_options,
+			"blob:none",
+			/*allow_implicit_combine=*/0);
 	}
 
 	if (version != protocol_v2 && !ref) {
 		packet_flush(fd[1]);
 		die(_("no matching remote head"));
 	}
 	if (version == protocol_v2) {
 		if (shallow->nr)
 			BUG("Protocol V2 does not provide shallows at this point in the fetch");
 		memset(&si, 0, sizeof(si));
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 647b2b220e..a0cc87c62b 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -1,18 +1,19 @@
 #include "cache.h"
 #include "commit.h"
 #include "config.h"
 #include "revision.h"
 #include "argv-array.h"
 #include "list-objects.h"
 #include "list-objects-filter.h"
 #include "list-objects-filter-options.h"
+#include "trace.h"
 
 static int parse_combine_filter(
 	struct list_objects_filter_options *filter_options,
 	const char *arg,
 	struct strbuf *errbuf);
 
 /*
  * Parse value of the argument to the "filter" keyword.
  * On the command line this looks like:
  *       --filter=<arg>
@@ -229,43 +230,107 @@ static int parse_combine_filter(
 
 cleanup:
 	strbuf_list_free(sub_specs);
 	if (result) {
 		list_objects_filter_release(filter_options);
 		memset(filter_options, 0, sizeof(*filter_options));
 	}
 	return result;
 }
 
-int parse_list_objects_filter(struct list_objects_filter_options *filter_options,
-			      const char *arg)
+static void add_url_encoded(struct strbuf *dest, const char *s)
 {
-	struct strbuf buf = STRBUF_INIT;
-	if (filter_options->choice)
-		die(_("multiple filter-specs cannot be combined"));
-	filter_options->filter_spec = strdup(arg);
-	if (gently_parse_list_objects_filter(filter_options, arg, &buf))
-		die("%s", buf.buf);
+	while (*s) {
+		if (*s <= ' ' || strchr(RESERVED_NON_WS, *s) ||
+			*s == '%' || *s == '+')
+			strbuf_addf(dest, "%%%02X", (int)*s);
+		else
+			strbuf_addf(dest, "%c", *s);
+		s++;
+	}
+}
+
+/*
+ * Returns a new filter-spec string by combining (with combine:) the two
+ * sub-specs. The caller gains ownership of a new string, and lhs and rhs are
+ * not freed.
+ */
+static char *combine_specs(const char *lhs, const char *rhs)
+{
+	struct strbuf combined = STRBUF_INIT;
+	if (starts_with(lhs, "combine:")) {
+		strbuf_addf(&combined, "%s", lhs);
+	} else {
+		strbuf_addf(&combined, "combine:");
+		add_url_encoded(&combined, lhs);
+	}
+	strbuf_addf(&combined, "+");
+
+	add_url_encoded(&combined, rhs);
+	trace_printf("Generated composite filter-spec: %s\n", combined.buf);
+	return strbuf_detach(&combined, NULL);
+}
+
+int parse_list_objects_filter(
+	struct list_objects_filter_options *filter_options,
+	const char *arg,
+	int allow_implicit_combine)
+{
+	struct strbuf errbuf = STRBUF_INIT;
+	if (filter_options->choice) {
+		struct list_objects_filter_options *lhs;
+
+		if (!allow_implicit_combine)
+			die(_("multiple filter-specs cannot be combined"));
+
+		lhs = xcalloc(1, sizeof(*lhs));
+		*lhs = *filter_options;
+		memset(filter_options, 0, sizeof(*filter_options));
+
+		filter_options->lhs = lhs;
+		filter_options->rhs = xcalloc(1, sizeof(*filter_options->rhs));
+		filter_options->choice = LOFC_COMBINE;
+
+		/*
+		 * Build up the filter-spec string using the already-parsed
+		 * portion (the lhs) and the to-be-parsed portion (the rhs).
+		 */
+		filter_options->filter_spec = combine_specs(
+			lhs->filter_spec, arg);
+		FREE_AND_NULL(lhs->filter_spec);
+
+		/*
+		 * The gentle parse function below will populate the rhs of the
+		 * combined filter. But the caller of *this* function sees
+		 * filter_options as the combined filter.
+		 */
+		filter_options = filter_options->rhs;
+	} else {
+		filter_options->filter_spec = strdup(arg);
+	}
+	if (gently_parse_list_objects_filter(filter_options, arg, &errbuf))
+		die("%s", errbuf.buf);
 	return 0;
 }
 
 int opt_parse_list_objects_filter(const struct option *opt,
 				  const char *arg, int unset)
 {
 	struct list_objects_filter_options *filter_options = opt->value;
 
 	if (unset || !arg) {
 		list_objects_filter_set_no_filter(filter_options);
 		return 0;
 	}
 
-	return parse_list_objects_filter(filter_options, arg);
+	return parse_list_objects_filter(
+		filter_options, arg, /*allow_implicit_combine=*/1);
 }
 
 void expand_list_objects_filter_spec(
 	const struct list_objects_filter_options *filter,
 	struct strbuf *expanded_spec)
 {
 	strbuf_init(expanded_spec, strlen(filter->filter_spec));
 	if (filter->choice == LOFC_BLOB_LIMIT)
 		strbuf_addf(expanded_spec, "blob:limit=%lu",
 			    filter->blob_limit_value);
diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index 6c0f0ecd08..a3ad00fde2 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -55,21 +55,22 @@ struct list_objects_filter_options {
 	/*
 	 * END choice-specific parsed values.
 	 */
 };
 
 /* Normalized command line arguments */
 #define CL_ARG__FILTER "filter"
 
 int parse_list_objects_filter(
 	struct list_objects_filter_options *filter_options,
-	const char *arg);
+	const char *arg,
+	int allow_implicit_combine);
 
 int opt_parse_list_objects_filter(const struct option *opt,
 				  const char *arg, int unset);
 
 #define OPT_PARSE_LIST_OBJECTS_FILTER(fo) \
 	{ OPTION_CALLBACK, 0, CL_ARG__FILTER, fo, N_("args"), \
 	  N_("object filtering"), 0, \
 	  opt_parse_list_objects_filter }
 
 /*
diff --git a/t/t5616-partial-clone.sh b/t/t5616-partial-clone.sh
index 9a8f9886b3..11536f4028 100755
--- a/t/t5616-partial-clone.sh
+++ b/t/t5616-partial-clone.sh
@@ -201,20 +201,39 @@ test_expect_success 'use fsck before and after manually fetching a missing subtr
 	test_line_count = 70 fetched_objects &&
 
 	awk -f print_1.awk fetched_objects |
 	xargs -n1 git -C dst cat-file -t >fetched_types &&
 
 	sort -u fetched_types >unique_types.observed &&
 	test_write_lines blob commit tree >unique_types.expected &&
 	test_cmp unique_types.expected unique_types.observed
 '
 
+test_expect_success 'implicitly construct combine: filter with repeated flags' '
+	GIT_TRACE=$(pwd)/trace git clone --bare \
+		--filter=blob:none --filter=tree:1 \
+		"file://$(pwd)/srv.bare" pc2 &&
+	grep "trace:.* git pack-objects .*--filter=combine:blob:none+tree:1" \
+		trace &&
+	git -C pc2 rev-list --objects --missing=allow-any HEAD >objects &&
+
+	# We should have gotten some root trees.
+	grep " $" objects &&
+	# Should not have gotten any non-root trees or blobs.
+	! grep " ." objects &&
+
+	xargs -n 1 git -C pc2 cat-file -t <objects >types &&
+	sort -u types >unique_types.actual &&
+	test_write_lines commit tree >unique_types.expected &&
+	test_cmp unique_types.expected unique_types.actual
+'
+
 test_expect_success 'partial clone fetches blobs pointed to by refs even if normally filtered out' '
 	rm -rf src dst &&
 	git init src &&
 	test_commit -C src x &&
 	test_config -C src uploadpack.allowfilter 1 &&
 	test_config -C src uploadpack.allowanysha1inwant 1 &&
 
 	# Create a tag pointing to a blob.
 	BLOB=$(echo blob-contents | git -C src hash-object --stdin -w) &&
 	git -C src tag myblob "$BLOB" &&
diff --git a/t/t6112-rev-list-filters-objects.sh b/t/t6112-rev-list-filters-objects.sh
index ddfacb1a1a..104248c73d 100755
--- a/t/t6112-rev-list-filters-objects.sh
+++ b/t/t6112-rev-list-filters-objects.sh
@@ -357,21 +357,30 @@ test_expect_success 'verify tree:3 includes everything expected' '
 
 test_expect_success 'combine:... for a simple combination' '
 	git -C r3 rev-list --objects --filter=combine:tree:2+blob:none HEAD \
 		>actual &&
 
 	expect_has HEAD "" &&
 	expect_has HEAD~1 "" &&
 	expect_has HEAD dir1 &&
 
 	# There are also 2 commit objects
-	test_line_count = 5 actual
+	test_line_count = 5 actual &&
+
+	cp actual expected &&
+
+	# Try again using repeated --filter - this is equivalent to a manual
+	# combine with "combine:...+..."
+	git -C r3 rev-list --objects --filter=combine:tree:2 \
+		--filter=blob:none HEAD >actual &&
+
+	test_cmp expected actual
 '
 
 test_expect_success 'combine:... with URL encoding' '
 	git -C r3 rev-list --objects \
 		--filter=combine:tree%3a2+blob:%6Eon%65 HEAD >actual &&
 
 	expect_has HEAD "" &&
 	expect_has HEAD~1 "" &&
 	expect_has HEAD dir1 &&
 
@@ -459,21 +468,46 @@ test_expect_success 'combine:... with more than two sub-filters' '
 	test_line_count = 7 actual &&
 
 	# Try again, this time making sure the last sub-filter is only
 	# URL-decoded once.
 	cp pattern1 pattern1+renamed% &&
 	cp actual expect &&
 
 	git -C r3 rev-list --objects \
 		--filter=combine:tree:3+blob:limit=40+sparse:path=../pattern1%2brenamed%25 \
 		HEAD >actual &&
-	test_cmp expect actual
+	test_cmp expect actual &&
+
+	# Use the same composite filter again, but with a pattern file name that
+	# requires encoding multiple characters, and use implicit filter
+	# combining.
+	cp pattern1 "p;at%ter+n" &&
+	GIT_TRACE=$(pwd)/trace git -C r3 rev-list --objects \
+		--filter=tree:3 --filter=blob:limit=40 \
+		--filter=sparse:path="../p;at%ter+n" \
+		HEAD >actual &&
+
+	test_cmp expect actual &&
+	grep "Generated composite filter-spec: combine:tree:3+blob:limit=40+sparse:path=../p%3Bat%25ter%2B" \
+		trace &&
+
+	# Repeat the above test, but this time, the characters to encode are in
+	# the LHS of the combined filter.
+	cp pattern1 "^~pattern" &&
+	GIT_TRACE=$(pwd)/trace git -C r3 rev-list --objects \
+		--filter=sparse:path="../^~pattern" \
+		--filter=tree:3 --filter=blob:limit=40 \
+		HEAD >actual &&
+
+	test_cmp expect actual &&
+	grep "Generated composite filter-spec: combine:sparse:path=../%5E%7Epattern+tree:3+blob:limit=40" \
+		trace
 '
 
 # Test provisional omit collection logic with a repo that has objects appearing
 # at multiple depths - first deeper than the filter's threshold, then shallow.
 
 test_expect_success 'setup r4' '
 	git init r4 &&
 
 	echo foo > r4/foo &&
 	mkdir r4/subdir &&
diff --git a/transport.c b/transport.c
index f1fcd2c4b0..63100da143 100644
--- a/transport.c
+++ b/transport.c
@@ -217,21 +217,24 @@ static int set_git_option(struct git_transport_options *opts,
 	} else if (!strcmp(name, TRANS_OPT_DEEPEN_RELATIVE)) {
 		opts->deepen_relative = !!value;
 		return 0;
 	} else if (!strcmp(name, TRANS_OPT_FROM_PROMISOR)) {
 		opts->from_promisor = !!value;
 		return 0;
 	} else if (!strcmp(name, TRANS_OPT_NO_DEPENDENTS)) {
 		opts->no_dependents = !!value;
 		return 0;
 	} else if (!strcmp(name, TRANS_OPT_LIST_OBJECTS_FILTER)) {
-		parse_list_objects_filter(&opts->filter_options, value);
+		parse_list_objects_filter(
+			&opts->filter_options,
+			value,
+			/*allow_implicit_combine=*/0);
 		return 0;
 	}
 	return 1;
 }
 
 static int connect_setup(struct transport *transport, int for_push)
 {
 	struct git_transport_data *data = transport->data;
 	int flags = transport->verbose > 0 ? CONNECT_VERBOSE : 0;
 
diff --git a/upload-pack.c b/upload-pack.c
index d2ea5eb20d..e3f2618600 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -877,21 +877,24 @@ static void receive_needs(struct packet_reader *reader, struct object_array *wan
 		if (process_deepen(reader->line, &depth))
 			continue;
 		if (process_deepen_since(reader->line, &deepen_since, &deepen_rev_list))
 			continue;
 		if (process_deepen_not(reader->line, &deepen_not, &deepen_rev_list))
 			continue;
 
 		if (skip_prefix(reader->line, "filter ", &arg)) {
 			if (!filter_capability_requested)
 				die("git upload-pack: filtering capability not negotiated");
-			parse_list_objects_filter(&filter_options, arg);
+			parse_list_objects_filter(
+				&filter_options,
+				arg,
+				/*allow_implicit_combine=*/0);
 			continue;
 		}
 
 		if (!skip_prefix(reader->line, "want ", &arg) ||
 		    parse_oid_hex(arg, &oid_buf, &features))
 			die("git upload-pack: protocol error, "
 			    "expected to get object ID, not '%s'", reader->line);
 
 		if (parse_feature_request(features, "deepen-relative"))
 			deepen_relative = 1;
@@ -1296,21 +1299,24 @@ static void process_args(struct packet_reader *request,
 			continue;
 		if (process_deepen_not(arg, &data->deepen_not,
 				       &data->deepen_rev_list))
 			continue;
 		if (!strcmp(arg, "deepen-relative")) {
 			data->deepen_relative = 1;
 			continue;
 		}
 
 		if (allow_filter && skip_prefix(arg, "filter ", &p)) {
-			parse_list_objects_filter(&filter_options, p);
+			parse_list_objects_filter(
+				&filter_options,
+				p,
+				/*allow_implicit_combine=*/0);
 			continue;
 		}
 
 		if ((git_env_bool("GIT_TEST_SIDEBAND_ALL", 0) ||
 		     allow_sideband_all) &&
 		    !strcmp(arg, "sideband-all")) {
 			data->writer.use_sideband = 1;
 			continue;
 		}