v6, 3 partsMerge renormalization, config renamed

Documentation/gitattributes.txt, Documentation/merge-config.txt, builtin/merge.c, cache.h, convert.c, environment.c, ll-merge.c, t/t6038-merge-text-auto.sh

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 564586b..da553ff 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -317,6 +317,17 @@ command is "cat").
 	smudge = cat
 ------------------------
 
+For best results, `clean` should not alter its output further if it is
+run twice ("clean->clean" should be equivalent to "clean"), and
+multiple `smudge` commands should not alter `clean`'s output
+("smudge->smudge->clean" should be equivalent to "clean").  See the
+section on merging below.
+
+The "indent" filter is well-behaved in this regard: it will not modify
+input that is already correctly indented.  In this case, the lack of a
+smudge filter means that the clean filter _must_ accept its own output
+without modifying it.
+
 
 Interaction between checkin/checkout attributes
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -331,6 +342,29 @@ In the check-out codepath, the blob content is first converted
 with `text`, and then `ident` and fed to `filter`.
 
 
+Merging branches with differing checkin/checkout attributes
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+If you have added attributes to a file that cause the canonical
+repository format for that file to change, such as adding a
+clean/smudge filter or text/eol/ident attributes, merging anything
+where the attribute is not in place would normally cause merge
+conflicts.
+
+To prevent these unnecessary merge conflicts, git can be told to run a
+virtual check-out and check-in of all three stages of a file when
+resolving a three-way merge by setting the `merge.renormalize`
+configuration variable.  This prevents changes caused by check-in
+conversion from causing spurious merge conflicts when a converted file
+is merged with an unconverted file.
+
+As long as a "smudge->clean" results in the same output as a "clean"
+even on files that are already smudged, this strategy will
+automatically resolve all filter-related conflicts.  Filters that do
+not act in this way may cause additional merge conflicts that must be
+resolved manually.
+
+
 Generating diff text
 ~~~~~~~~~~~~~~~~~~~~
 
diff --git a/Documentation/merge-config.txt b/Documentation/merge-config.txt
index a403155..b72f533 100644
--- a/Documentation/merge-config.txt
+++ b/Documentation/merge-config.txt
@@ -15,6 +15,16 @@ merge.renameLimit::
 	during a merge; if not specified, defaults to the value of
 	diff.renameLimit.
 
+merge.renormalize::
+	Tell git that canonical representation of files in the
+	repository has changed over time (e.g. earlier commits record
+	text files with CRLF line endings, but recent ones use LF line
+	endings).  In such a repository, git can convert the data
+	recorded in commits to a canonical form before performing a
+	merge to reduce unnecessary conflicts.  For more information,
+	see section "Merging branches with differing checkin/checkout
+	attributes" in linkgit:gitattributes[5].
+
 merge.stat::
 	Whether to print the diffstat between ORIG_HEAD and the merge result
 	at the end of the merge.  True by default.
diff --git a/builtin/merge.c b/builtin/merge.c
index 37ce4f5..b836e9c 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -503,6 +503,9 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 		return git_config_string(&pull_octopus, k, v);
 	else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
 		option_log = git_config_bool(k, v);
+	else if (!strcmp(k, "merge.renormalize")) {
+		merge_renormalize = git_config_bool(k, v);
+	}
 	return git_diff_ui_config(k, v, cb);
 }
 
diff --git a/cache.h b/cache.h
index c9fa3df..ed73da8 100644
--- a/cache.h
+++ b/cache.h
@@ -551,6 +551,7 @@ extern int read_replace_refs;
 extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
+extern int merge_renormalize;
 
 enum safe_crlf {
 	SAFE_CRLF_FALSE = 0,
@@ -1054,6 +1055,7 @@ extern void trace_argv_printf(const char **argv, const char *format, ...);
 extern int convert_to_git(const char *path, const char *src, size_t len,
                           struct strbuf *dst, enum safe_crlf checksafe);
 extern int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst);
+extern int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst);
 
 /* add */
 /*
diff --git a/convert.c b/convert.c
index e41a31e..0203be8 100644
--- a/convert.c
+++ b/convert.c
@@ -93,7 +93,8 @@ static int is_binary(unsigned long size, struct text_stat *stats)
 	return 0;
 }
 
-static enum eol determine_output_conversion(enum action action) {
+static enum eol determine_output_conversion(enum action action)
+{
 	switch (action) {
 	case CRLF_BINARY:
 		return EOL_UNSET;
@@ -693,7 +694,8 @@ static int git_path_check_ident(const char *path, struct git_attr_check *check)
 	return !!ATTR_TRUE(value);
 }
 
-enum action determine_action(enum action text_attr, enum eol eol_attr) {
+static enum action determine_action(enum action text_attr, enum eol eol_attr)
+{
 	if (text_attr == CRLF_BINARY)
 		return CRLF_BINARY;
 	if (eol_attr == EOL_LF)
@@ -773,3 +775,13 @@ int convert_to_working_tree(const char *path, const char *src, size_t len, struc
 	}
 	return ret | apply_filter(path, src, len, dst, filter);
 }
+
+int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
+{
+	int ret = convert_to_working_tree(path, src, len, dst);
+	if (ret) {
+		src = dst->buf;
+		len = dst->len;
+	}
+	return ret | convert_to_git(path, src, len, dst, 0);
+}
diff --git a/environment.c b/environment.c
index 83d38d3..81a3682 100644
--- a/environment.c
+++ b/environment.c
@@ -53,6 +53,7 @@ enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 char *notes_ref_name;
 int grafts_replace_parents = 1;
 int core_apply_sparse_checkout;
+int merge_renormalize;
 
 /* Parallel index stat data preload? */
 int core_preload_index = 0;
diff --git a/ll-merge.c b/ll-merge.c
index 3764a1a..5068fe0 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -321,6 +321,16 @@ static int git_path_check_merge(const char *path, struct git_attr_check check[2]
 	return git_checkattr(path, 2, check);
 }
 
+static void normalize_file(mmfile_t *mm, const char *path)
+{
+	struct strbuf strbuf = STRBUF_INIT;
+	if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
+		free(mm->ptr);
+		mm->size = strbuf.len;
+		mm->ptr = strbuf_detach(&strbuf, NULL);
+	}
+}
+
 int ll_merge(mmbuffer_t *result_buf,
 	     const char *path,
 	     mmfile_t *ancestor, const char *ancestor_label,
@@ -334,6 +344,11 @@ int ll_merge(mmbuffer_t *result_buf,
 	const struct ll_merge_driver *driver;
 	int virtual_ancestor = flag & 01;
 
+	if (merge_renormalize) {
+		normalize_file(ancestor, path);
+		normalize_file(ours, path);
+		normalize_file(theirs, path);
+	}
 	if (!git_path_check_merge(path, check)) {
 		ll_driver_name = check[0].value;
 		if (check[1].value) {
diff --git a/t/t6038-merge-text-auto.sh b/t/t6038-merge-text-auto.sh
new file mode 100755
index 0000000..127baf8
--- /dev/null
+++ b/t/t6038-merge-text-auto.sh
@@ -0,0 +1,64 @@
+#!/bin/sh
+
+test_description='CRLF merge conflict across text=auto change'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	git config merge.renormalize true &&
+	git config core.autocrlf false &&
+	echo first line | append_cr >file &&
+	echo first line >control_file &&
+	echo only line >inert_file &&
+	git add file control_file inert_file &&
+	git commit -m "Initial" &&
+	git tag initial &&
+	git branch side &&
+	echo "* text=auto" >.gitattributes &&
+	touch file &&
+	git add .gitattributes file &&
+	git commit -m "normalize file" &&
+	echo same line | append_cr >>file &&
+	echo same line >>control_file &&
+	git add file control_file &&
+	git commit -m "add line from a" &&
+	git tag a &&
+	git rm .gitattributes &&
+	rm file &&
+	git checkout file &&
+	git commit -m "remove .gitattributes" &&
+	git tag c &&
+	git checkout side &&
+	echo same line | append_cr >>file &&
+	echo same line >>control_file &&
+	git add file control_file &&
+	git commit -m "add line from b" &&
+	git tag b &&
+	git checkout master
+'
+
+test_expect_success 'Check merging after setting text=auto' '
+	git reset --hard a &&
+	git merge b &&
+	cat file | remove_cr >file.temp &&
+	test_cmp file file.temp
+'
+
+test_expect_success 'Check merging addition of text=auto' '
+	git reset --hard b &&
+	git merge a &&
+	cat file | remove_cr >file.temp &&
+	test_cmp file file.temp
+'
+
+test_expect_failure 'Test delete/normalize conflict' '
+	git checkout side &&
+	git reset --hard initial &&
+	git rm file &&
+	git commit -m "remove file" &&
+	git checkout master &&
+	git reset --hard a^ &&
+	git merge side
+'
+
+test_done

merge-recursive.c, t/t6038-merge-text-auto.sh

diff --git a/merge-recursive.c b/merge-recursive.c
index 856e98c..593c0b1 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1056,6 +1056,53 @@ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
 	return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
 }
 
+static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
+{
+	void *buf;
+	enum object_type type;
+	unsigned long size;
+	buf = read_sha1_file(sha1, &type, &size);
+	if (!buf)
+		return error("cannot read object %s", sha1_to_hex(sha1));
+	if (type != OBJ_BLOB) {
+		free(buf);
+		return error("object %s is not a blob", sha1_to_hex(sha1));
+	}
+	strbuf_attach(dst, buf, size, size + 1);
+	return 0;
+}
+
+static int blob_unchanged(const unsigned char *o_sha,
+			  const unsigned char *a_sha,
+			  const char *path)
+{
+	struct strbuf o = STRBUF_INIT;
+	struct strbuf a = STRBUF_INIT;
+	int ret = 0; /* assume changed for safety */
+
+	if (sha_eq(o_sha, a_sha))
+		return 1;
+	if (!merge_renormalize)
+		return 0;
+
+	assert(o_sha && a_sha);
+	if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
+		goto error_return;
+	/*
+	 * Note: binary | is used so that both renormalizations are
+	 * performed.  Comparison can be skipped if both files are
+	 * unchanged since their sha1s have already been compared.
+	 */
+	if (renormalize_buffer(path, o.buf, o.len, &o) |
+	    renormalize_buffer(path, a.buf, o.len, &a))
+		ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+
+error_return:
+	strbuf_release(&o);
+	strbuf_release(&a);
+	return ret;
+}
+
 /* Per entry merge function */
 static int process_entry(struct merge_options *o,
 			 const char *path, struct stage_data *entry)
@@ -1075,8 +1122,8 @@ static int process_entry(struct merge_options *o,
 	if (o_sha && (!a_sha || !b_sha)) {
 		/* Case A: Deleted in one */
 		if ((!a_sha && !b_sha) ||
-		    (sha_eq(a_sha, o_sha) && !b_sha) ||
-		    (!a_sha && sha_eq(b_sha, o_sha))) {
+		    (!b_sha && blob_unchanged(o_sha, a_sha, path)) ||
+		    (!a_sha && blob_unchanged(o_sha, b_sha, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)
diff --git a/t/t6038-merge-text-auto.sh b/t/t6038-merge-text-auto.sh
index 127baf8..d1ab86e 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6038-merge-text-auto.sh
@@ -51,7 +51,7 @@ test_expect_success 'Check merging addition of text=auto' '
 	test_cmp file file.temp
 '
 
-test_expect_failure 'Test delete/normalize conflict' '
+test_expect_success 'Test delete/normalize conflict' '
 	git checkout side &&
 	git reset --hard initial &&
 	git rm file &&

diff --git a/convert.c b/convert.c
index 0203be8..01de9a8 100644
--- a/convert.c
+++ b/convert.c
@@ -741,7 +741,9 @@ int convert_to_git(const char *path, const char *src, size_t len,
 	return ret | ident_to_git(path, src, len, dst, ident);
 }
 
-int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
+static int convert_to_working_tree_internal(const char *path, const char *src,
+					    size_t len, struct strbuf *dst,
+					    int normalizing)
 {
 	struct git_attr_check check[5];
 	enum action action = CRLF_GUESS;
@@ -767,18 +769,29 @@ int convert_to_working_tree(const char *path, const char *src, size_t len, struc
 		src = dst->buf;
 		len = dst->len;
 	}
-	action = determine_action(action, eol_attr);
-	ret |= crlf_to_worktree(path, src, len, dst, action);
-	if (ret) {
-		src = dst->buf;
-		len = dst->len;
+	/*
+	 * CRLF conversion can be skipped if normalizing, unless there
+	 * is a smudge filter.  The filter might expect CRLFs.
+	 */
+	if (filter || !normalizing) {
+		action = determine_action(action, eol_attr);
+		ret |= crlf_to_worktree(path, src, len, dst, action);
+		if (ret) {
+			src = dst->buf;
+			len = dst->len;
+		}
 	}
 	return ret | apply_filter(path, src, len, dst, filter);
 }
 
+int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
+{
+	return convert_to_working_tree_internal(path, src, len, dst, 0);
+}
+
 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 {
-	int ret = convert_to_working_tree(path, src, len, dst);
+	int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 	if (ret) {
 		src = dst->buf;
 		len = dst->len;

diff --git a/merge-recursive.c b/merge-recursive.c
index 5ad8fc9..2b55fc2 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1074,7 +1074,7 @@ static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
 
 static int blob_unchanged(const unsigned char *o_sha,
 			  const unsigned char *a_sha,
-			  const char *path)
+			  int renormalize, const char *path)
 {
 	struct strbuf o = STRBUF_INIT;
 	struct strbuf a = STRBUF_INIT;
@@ -1082,7 +1082,7 @@ static int blob_unchanged(const unsigned char *o_sha,
 
 	if (sha_eq(o_sha, a_sha))
 		return 1;
-	if (!merge_renormalize)
+	if (!renormalize)
 		return 0;
 
 	assert(o_sha && a_sha);
@@ -1112,6 +1112,7 @@ static int process_entry(struct merge_options *o,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
+	int normalize = merge_renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -1122,8 +1123,8 @@ static int process_entry(struct merge_options *o,
 	if (o_sha && (!a_sha || !b_sha)) {
 		/* Case A: Deleted in one */
 		if ((!a_sha && !b_sha) ||
-		    (!b_sha && blob_unchanged(o_sha, a_sha, path)) ||
-		    (!a_sha && blob_unchanged(o_sha, b_sha, path))) {
+		    (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
+		    (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)

merge-recursive.c, merge-recursive.h

diff --git a/merge-recursive.c b/merge-recursive.c
index 2b55fc2..8a49844 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1112,7 +1112,7 @@ static int process_entry(struct merge_options *o,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
-	int normalize = merge_renormalize;
+	int normalize = o->renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -1484,6 +1484,7 @@ void init_merge_options(struct merge_options *o)
 	o->buffer_output = 1;
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
+	o->renormalize = merge_renormalize;
 	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =
diff --git a/merge-recursive.h b/merge-recursive.h
index b831293..cdb97e9 100644
--- a/merge-recursive.h
+++ b/merge-recursive.h
@@ -17,6 +17,7 @@ struct merge_options {
 	int verbosity;
 	int diff_rename_limit;
 	int merge_rename_limit;
+	int renormalize;
 	int call_depth;
 	struct strbuf obuf;
 	struct string_list current_file_set;

builtin/checkout.c, ll-merge.c, ll-merge.h, merge-file.c, merge-recursive.c, rerere.c

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 1994be9..5a7ae03 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -150,8 +150,12 @@ static int checkout_merged(int pos, struct checkout *state)
 	read_mmblob(&ours, active_cache[pos+1]->sha1);
 	read_mmblob(&theirs, active_cache[pos+2]->sha1);
 
+	/*
+	 * NEEDSWORK: re-create conflicts from merges with
+	 * merge.renormalize set, too
+	 */
 	status = ll_merge(&result_buf, path, &ancestor, "base",
-			  &ours, "ours", &theirs, "theirs", 0);
+			  &ours, "ours", &theirs, "theirs", 0, 0);
 	free(ancestor.ptr);
 	free(ours.ptr);
 	free(theirs.ptr);
diff --git a/ll-merge.c b/ll-merge.c
index 5068fe0..0a0e04d 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -336,7 +336,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	     mmfile_t *ancestor, const char *ancestor_label,
 	     mmfile_t *ours, const char *our_label,
 	     mmfile_t *theirs, const char *their_label,
-	     int flag)
+	     int renormalize, int flag)
 {
 	static struct git_attr_check check[2];
 	const char *ll_driver_name = NULL;
@@ -344,7 +344,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	const struct ll_merge_driver *driver;
 	int virtual_ancestor = flag & 01;
 
-	if (merge_renormalize) {
+	if (renormalize) {
 		normalize_file(ancestor, path);
 		normalize_file(ours, path);
 		normalize_file(theirs, path);
diff --git a/ll-merge.h b/ll-merge.h
index 57754cc..dd81a1e 100644
--- a/ll-merge.h
+++ b/ll-merge.h
@@ -10,7 +10,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	     mmfile_t *ancestor, const char *ancestor_label,
 	     mmfile_t *ours, const char *our_label,
 	     mmfile_t *theirs, const char *their_label,
-	     int flag);
+	     int renormalize, int flag);
 
 int ll_merge_marker_size(const char *path);
 
diff --git a/merge-file.c b/merge-file.c
index db4d0d5..5afdc01 100644
--- a/merge-file.c
+++ b/merge-file.c
@@ -37,7 +37,7 @@ static void *three_way_filemerge(const char *path, mmfile_t *base, mmfile_t *our
 	 * common ancestor.
 	 */
 	merge_status = ll_merge(&res, path, base, NULL,
-				our, ".our", their, ".their", 0);
+				our, ".our", their, ".their", 0, 0);
 	if (merge_status < 0)
 		return NULL;
 
diff --git a/merge-recursive.c b/merge-recursive.c
index 8a49844..4838939 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -647,6 +647,7 @@ static int merge_3way(struct merge_options *o,
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
+				o->renormalize,
 				(!!o->call_depth) | (favor << 1));
 
 	free(name1);
diff --git a/rerere.c b/rerere.c
index 2197890..17dcc3c 100644
--- a/rerere.c
+++ b/rerere.c
@@ -319,9 +319,13 @@ static int handle_cache(const char *path, unsigned char *sha1, const char *outpu
 		if (!mmfile[i].ptr && !mmfile[i].size)
 			mmfile[i].ptr = xstrdup("");
 	}
+	/*
+	 * NEEDSWORK: handle conflicts from merges with
+	 * merge.renormalize set, too
+	 */
 	ll_merge(&result, path, &mmfile[0], NULL,
 		 &mmfile[1], "ours",
-		 &mmfile[2], "theirs", 0);
+		 &mmfile[2], "theirs", 0, 0);
 	for (i = 0; i < 3; i++)
 		free(mmfile[i].ptr);
 
@@ -361,7 +365,7 @@ static int find_conflict(struct string_list *conflict)
 	return 0;
 }
 
-static int merge(const char *name, const char *path)
+static int merge(const char *name, int renormalize, const char *path)
 {
 	int ret;
 	mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
@@ -376,7 +380,8 @@ static int merge(const char *name, const char *path)
 		ret = 1;
 		goto out;
 	}
-	ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
+	ret = ll_merge(&result, path, &base, NULL,
+			&cur, "", &other, "", renormalize, 0);
 	if (!ret) {
 		FILE *f = fopen(path, "w");
 		if (!f)
@@ -424,7 +429,7 @@ static int update_paths(struct string_list *update)
 	return status;
 }
 
-static int do_plain_rerere(struct string_list *rr, int fd)
+static int do_plain_rerere(struct string_list *rr, int fd, int renormalize)
 {
 	struct string_list conflict = { NULL, 0, 0, 1 };
 	struct string_list update = { NULL, 0, 0, 1 };
@@ -469,7 +474,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 		const char *name = (const char *)rr->items[i].util;
 
 		if (has_rerere_resolution(name)) {
-			if (!merge(name, path)) {
+			if (!merge(name, renormalize, path)) {
 				if (rerere_autoupdate)
 					string_list_insert(path, &update);
 				fprintf(stderr,
@@ -553,7 +558,7 @@ int rerere(int flags)
 	fd = setup_rerere(&merge_rr, flags);
 	if (fd < 0)
 		return 0;
-	return do_plain_rerere(&merge_rr, fd);
+	return do_plain_rerere(&merge_rr, fd, merge_renormalize);
 }
 
 static int rerere_forget_one_path(const char *path, struct string_list *rr)

diff --git a/builtin/rerere.c b/builtin/rerere.c
index 0048f9e..295fe75 100644
--- a/builtin/rerere.c
+++ b/builtin/rerere.c
@@ -1,13 +1,16 @@
 #include "builtin.h"
 #include "cache.h"
 #include "dir.h"
+#include "parse-options.h"
 #include "string-list.h"
 #include "rerere.h"
 #include "xdiff/xdiff.h"
 #include "xdiff-interface.h"
 
-static const char git_rerere_usage[] =
-"git rerere [clear | status | diff | gc]";
+static const char * const rerere_usage[] = {
+	"git rerere [clear | status | diff | gc]",
+	NULL,
+};
 
 /* these values are days */
 static int cutoff_noresolve = 15;
@@ -103,25 +106,26 @@ static int diff_two(const char *file1, const char *label1,
 int cmd_rerere(int argc, const char **argv, const char *prefix)
 {
 	struct string_list merge_rr = { NULL, 0, 0, 1 };
-	int i, fd, flags = 0;
-
-	if (2 < argc) {
-		if (!strcmp(argv[1], "-h"))
-			usage(git_rerere_usage);
-		if (!strcmp(argv[1], "--rerere-autoupdate"))
-			flags = RERERE_AUTOUPDATE;
-		else if (!strcmp(argv[1], "--no-rerere-autoupdate"))
-			flags = RERERE_NOAUTOUPDATE;
-		if (flags) {
-			argc--;
-			argv++;
-		}
-	}
-	if (argc < 2)
+	int i, fd, autoupdate = -1, flags = 0;
+
+	struct option options[] = {
+		OPT_SET_INT(0, "rerere-autoupdate", &autoupdate,
+			"register clean resolutions in index", 1),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, prefix, options, rerere_usage, 0);
+
+	if (autoupdate == 1)
+		flags = RERERE_AUTOUPDATE;
+	if (autoupdate == 0)
+		flags = RERERE_NOAUTOUPDATE;
+
+	if (argc < 1)
 		return rerere(flags);
 
-	if (!strcmp(argv[1], "forget")) {
-		const char **pathspec = get_pathspec(prefix, argv + 2);
+	if (!strcmp(argv[0], "forget")) {
+		const char **pathspec = get_pathspec(prefix, argv + 1);
 		return rerere_forget(pathspec);
 	}
 
@@ -129,26 +133,26 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
 	if (fd < 0)
 		return 0;
 
-	if (!strcmp(argv[1], "clear")) {
+	if (!strcmp(argv[0], "clear")) {
 		for (i = 0; i < merge_rr.nr; i++) {
 			const char *name = (const char *)merge_rr.items[i].util;
 			if (!has_rerere_resolution(name))
 				unlink_rr_item(name);
 		}
 		unlink_or_warn(git_path("rr-cache/MERGE_RR"));
-	} else if (!strcmp(argv[1], "gc"))
+	} else if (!strcmp(argv[0], "gc"))
 		garbage_collect(&merge_rr);
-	else if (!strcmp(argv[1], "status"))
+	else if (!strcmp(argv[0], "status"))
 		for (i = 0; i < merge_rr.nr; i++)
 			printf("%s\n", merge_rr.items[i].string);
-	else if (!strcmp(argv[1], "diff"))
+	else if (!strcmp(argv[0], "diff"))
 		for (i = 0; i < merge_rr.nr; i++) {
 			const char *path = merge_rr.items[i].string;
 			const char *name = (const char *)merge_rr.items[i].util;
 			diff_two(rerere_path(name, "preimage"), path, path, path);
 		}
 	else
-		usage(git_rerere_usage);
+		usage_with_options(rerere_usage, options);
 
 	string_list_clear(&merge_rr, 1);
 	return 0;

builtin/commit.c, builtin/merge.c, builtin/rerere.c, builtin/revert.c, rerere.c, rerere.h

diff --git a/builtin/commit.c b/builtin/commit.c
index 3d99cf9..56c998f 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1377,6 +1377,10 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 		     "new_index file. Check that disk is not full or quota is\n"
 		     "not exceeded, and then \"git reset HEAD\" to recover.");
 
+	/*
+	 * NEEDSWORK: use RERERE_RENORMALIZE after a merge with
+	 * merge.renormalize set
+	 */
 	rerere(0);
 	run_hook(get_index_file(), "post-commit", NULL);
 	if (amend && !no_post_rewrite) {
diff --git a/builtin/merge.c b/builtin/merge.c
index b836e9c..823b76b 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -822,7 +822,7 @@ static int finish_automerge(struct commit_list *common,
 static int suggest_conflicts(void)
 {
 	FILE *fp;
-	int pos;
+	int pos, flag;
 
 	fp = fopen(git_path("MERGE_MSG"), "a");
 	if (!fp)
@@ -841,7 +841,10 @@ static int suggest_conflicts(void)
 		}
 	}
 	fclose(fp);
-	rerere(allow_rerere_auto);
+	flag = allow_rerere_auto;
+	if (merge_renormalize)
+		flag |= RERERE_RENORMALIZE;
+	rerere(flag);
 	printf("Automatic merge failed; "
 			"fix conflicts and then commit the result.\n");
 	return 1;
diff --git a/builtin/rerere.c b/builtin/rerere.c
index 295fe75..4009c01 100644
--- a/builtin/rerere.c
+++ b/builtin/rerere.c
@@ -111,15 +111,19 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		OPT_SET_INT(0, "rerere-autoupdate", &autoupdate,
 			"register clean resolutions in index", 1),
+		{ OPTION_BIT, 0, "renormalize-before-merge", &flags, NULL,
+			"simplify conflict hunks for normalization changes",
+			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL,
+			RERERE_RENORMALIZE },
 		OPT_END(),
 	};
 
 	argc = parse_options(argc, argv, prefix, options, rerere_usage, 0);
 
 	if (autoupdate == 1)
-		flags = RERERE_AUTOUPDATE;
+		flags |= RERERE_AUTOUPDATE;
 	if (autoupdate == 0)
-		flags = RERERE_NOAUTOUPDATE;
+		flags |= RERERE_NOAUTOUPDATE;
 
 	if (argc < 1)
 		return rerere(flags);
diff --git a/builtin/revert.c b/builtin/revert.c
index 853e9e4..c694801 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -338,7 +338,7 @@ static void do_recursive_merge(struct commit *base, struct commit *next,
 	rollback_lock_file(&index_lock);
 
 	if (!clean) {
-		int i;
+		int i, flags;
 		strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 		for (i = 0; i < active_nr;) {
 			struct cache_entry *ce = active_cache[i++];
@@ -354,7 +354,10 @@ static void do_recursive_merge(struct commit *base, struct commit *next,
 		write_message(msgbuf, defmsg);
 		fprintf(stderr, "Automatic %s failed.%s\n",
 			me, help_msg());
-		rerere(allow_rerere_auto);
+		flags = allow_rerere_auto;
+		if (o.renormalize)
+			flags |= RERERE_RENORMALIZE;
+		rerere(flags);
 		exit(1);
 	}
 	write_message(msgbuf, defmsg);
@@ -481,6 +484,10 @@ static int do_pick_commit(void)
 		if (res) {
 			fprintf(stderr, "Automatic %s with strategy %s failed.%s\n",
 				me, strategy, help_msg());
+			/*
+			 * NEEDSWORK: use RERERE_RENORMALIZE after
+			 * a merge with merge.renormalize set
+			 */
 			rerere(allow_rerere_auto);
 			exit(1);
 		}
diff --git a/rerere.c b/rerere.c
index 17dcc3c..8767024 100644
--- a/rerere.c
+++ b/rerere.c
@@ -553,12 +553,13 @@ int setup_rerere(struct string_list *merge_rr, int flags)
 int rerere(int flags)
 {
 	struct string_list merge_rr = { NULL, 0, 0, 1 };
-	int fd;
+	int fd, renormalize;
 
 	fd = setup_rerere(&merge_rr, flags);
 	if (fd < 0)
 		return 0;
-	return do_plain_rerere(&merge_rr, fd, merge_renormalize);
+	renormalize = (flags & RERERE_RENORMALIZE) ? 1 : 0;
+	return do_plain_rerere(&merge_rr, fd, renormalize);
 }
 
 static int rerere_forget_one_path(const char *path, struct string_list *rr)
diff --git a/rerere.h b/rerere.h
index eaa9004..a73555f 100644
--- a/rerere.h
+++ b/rerere.h
@@ -5,6 +5,7 @@
 
 #define RERERE_AUTOUPDATE   01
 #define RERERE_NOAUTOUPDATE 02
+#define RERERE_RENORMALIZE  04
 
 extern int setup_rerere(struct string_list *, int);
 extern int rerere(int);

diff --git a/t/t6038-merge-text-auto.sh b/t/t6038-merge-text-auto.sh
index d1ab86e..e21b5d2 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6038-merge-text-auto.sh
@@ -1,58 +1,94 @@
 #!/bin/sh
 
-test_description='CRLF merge conflict across text=auto change'
+test_description='CRLF merge conflict across text=auto change
+
+* [master] remove .gitattributes
+ ! [side] add line from b
+--
+ + [side] add line from b
+*  [master] remove .gitattributes
+*  [master^] add line from a
+*  [master~2] normalize file
+*+ [side^] Initial
+'
 
 . ./test-lib.sh
 
 test_expect_success setup '
 	git config merge.renormalize true &&
 	git config core.autocrlf false &&
+
 	echo first line | append_cr >file &&
 	echo first line >control_file &&
 	echo only line >inert_file &&
+
 	git add file control_file inert_file &&
+	test_tick &&
 	git commit -m "Initial" &&
 	git tag initial &&
 	git branch side &&
+
 	echo "* text=auto" >.gitattributes &&
 	touch file &&
 	git add .gitattributes file &&
+	test_tick &&
 	git commit -m "normalize file" &&
+
 	echo same line | append_cr >>file &&
 	echo same line >>control_file &&
 	git add file control_file &&
+	test_tick &&
 	git commit -m "add line from a" &&
 	git tag a &&
+
 	git rm .gitattributes &&
 	rm file &&
 	git checkout file &&
+	test_tick &&
 	git commit -m "remove .gitattributes" &&
 	git tag c &&
+
 	git checkout side &&
 	echo same line | append_cr >>file &&
 	echo same line >>control_file &&
 	git add file control_file &&
+	test_tick &&
 	git commit -m "add line from b" &&
 	git tag b &&
+
 	git checkout master
 '
 
-test_expect_success 'Check merging after setting text=auto' '
+test_expect_success 'Merge after setting text=auto' '
+	cat <<-\EOF >expected &&
+	first line
+	same line
+	EOF
+
+	git rm -fr . &&
+	rm -f .gitattributes &&
 	git reset --hard a &&
 	git merge b &&
-	cat file | remove_cr >file.temp &&
-	test_cmp file file.temp
+	test_cmp expected file
 '
 
-test_expect_success 'Check merging addition of text=auto' '
+test_expect_success 'Merge addition of text=auto' '
+	cat <<-\EOF >expected &&
+	first line
+	same line
+	EOF
+
+	git rm -fr . &&
+	rm -f .gitattributes &&
 	git reset --hard b &&
 	git merge a &&
-	cat file | remove_cr >file.temp &&
-	test_cmp file file.temp
+	test_cmp expected file
 '
 
 test_expect_success 'Test delete/normalize conflict' '
-	git checkout side &&
+	git checkout -f side &&
+	git rm -fr . &&
+	rm -f .gitattributes &&
 	git reset --hard initial &&
 	git rm file &&
 	git commit -m "remove file" &&

diff --git a/t/t6038-merge-text-auto.sh b/t/t6038-merge-text-auto.sh
index e21b5d2..a7ea4b6 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6038-merge-text-auto.sh
@@ -85,6 +85,47 @@ test_expect_success 'Merge addition of text=auto' '
 	test_cmp expected file
 '
 
+test_expect_failure 'checkout -m after setting text=auto' '
+	cat <<-\EOF >expected &&
+	first line
+	same line
+	EOF
+
+	git rm -fr . &&
+	rm -f .gitattributes &&
+	git reset --hard initial &&
+	git checkout a -- . &&
+	git checkout -m b &&
+	test_cmp expected file
+'
+
+test_expect_failure 'checkout -m addition of text=auto' '
+	cat <<-\EOF >expected &&
+	first line
+	same line
+	EOF
+
+	git rm -fr . &&
+	rm -f .gitattributes file &&
+	git reset --hard initial &&
+	git checkout b -- . &&
+	git checkout -m a &&
+	test_cmp expected file
+'
+
+test_expect_failure 'cherry-pick patch from after text=auto was added' '
+	append_cr <<-\EOF >expected &&
+	first line
+	same line
+	EOF
+
+	git rm -fr . &&
+	git reset --hard b &&
+	test_must_fail git cherry-pick a >err 2>&1 &&
+	grep "[Nn]othing added" err &&
+	test_cmp expected file
+'
+
 test_expect_success 'Test delete/normalize conflict' '
 	git checkout -f side &&
 	git rm -fr . &&

diff --git a/t/t6038-merge-text-auto.sh b/t/t6038-merge-text-auto.sh
index a7ea4b6..52d0dc4 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6038-merge-text-auto.sh
@@ -15,7 +15,6 @@ test_description='CRLF merge conflict across text=auto change
 . ./test-lib.sh
 
 test_expect_success setup '
-	git config merge.renormalize true &&
 	git config core.autocrlf false &&
 
 	echo first line | append_cr >file &&
@@ -59,12 +58,19 @@ test_expect_success setup '
 	git checkout master
 '
 
+test_expect_success 'set up fuzz_conflict() helper' '
+	fuzz_conflict() {
+		sed -e "s/^\([<>=]......\) .*/\1/" "$@"
+	}
+'
+
 test_expect_success 'Merge after setting text=auto' '
 	cat <<-\EOF >expected &&
 	first line
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes &&
 	git reset --hard a &&
@@ -78,6 +84,7 @@ test_expect_success 'Merge addition of text=auto' '
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes &&
 	git reset --hard b &&
@@ -85,12 +92,51 @@ test_expect_success 'Merge addition of text=auto' '
 	test_cmp expected file
 '
 
+test_expect_success 'Detect CRLF/LF conflict after setting text=auto' '
+	q_to_cr <<-\EOF >expected &&
+	<<<<<<<
+	first line
+	same line
+	=======
+	first lineQ
+	same lineQ
+	>>>>>>>
+	EOF
+
+	git config merge.renormalize false &&
+	rm -f .gitattributes &&
+	git reset --hard a &&
+	test_must_fail git merge b &&
+	fuzz_conflict file >file.fuzzy &&
+	test_cmp expected file.fuzzy
+'
+
+test_expect_success 'Detect LF/CRLF conflict from addition of text=auto' '
+	q_to_cr <<-\EOF >expected &&
+	<<<<<<<
+	first lineQ
+	same lineQ
+	=======
+	first line
+	same line
+	>>>>>>>
+	EOF
+
+	git config merge.renormalize false &&
+	rm -f .gitattributes &&
+	git reset --hard b &&
+	test_must_fail git merge a &&
+	fuzz_conflict file >file.fuzzy &&
+	test_cmp expected file.fuzzy
+'
+
 test_expect_failure 'checkout -m after setting text=auto' '
 	cat <<-\EOF >expected &&
 	first line
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes &&
 	git reset --hard initial &&
@@ -105,6 +151,7 @@ test_expect_failure 'checkout -m addition of text=auto' '
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	rm -f .gitattributes file &&
 	git reset --hard initial &&
@@ -119,6 +166,7 @@ test_expect_failure 'cherry-pick patch from after text=auto was added' '
 	same line
 	EOF
 
+	git config merge.renormalize true &&
 	git rm -fr . &&
 	git reset --hard b &&
 	test_must_fail git cherry-pick a >err 2>&1 &&

diff --git a/merge-recursive.c b/merge-recursive.c
index 5ad8fc9..2b55fc2 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1074,7 +1074,7 @@ static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
 
 static int blob_unchanged(const unsigned char *o_sha,
 			  const unsigned char *a_sha,
-			  const char *path)
+			  int renormalize, const char *path)
 {
 	struct strbuf o = STRBUF_INIT;
 	struct strbuf a = STRBUF_INIT;
@@ -1082,7 +1082,7 @@ static int blob_unchanged(const unsigned char *o_sha,
 
 	if (sha_eq(o_sha, a_sha))
 		return 1;
-	if (!merge_renormalize)
+	if (!renormalize)
 		return 0;
 
 	assert(o_sha && a_sha);
@@ -1112,6 +1112,7 @@ static int process_entry(struct merge_options *o,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
+	int normalize = merge_renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -1122,8 +1123,8 @@ static int process_entry(struct merge_options *o,
 	if (o_sha && (!a_sha || !b_sha)) {
 		/* Case A: Deleted in one */
 		if ((!a_sha && !b_sha) ||
-		    (!b_sha && blob_unchanged(o_sha, a_sha, path)) ||
-		    (!a_sha && blob_unchanged(o_sha, b_sha, path))) {
+		    (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
+		    (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)

merge-recursive.c, merge-recursive.h

diff --git a/merge-recursive.c b/merge-recursive.c
index 2b55fc2..8a49844 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1112,7 +1112,7 @@ static int process_entry(struct merge_options *o,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
-	int normalize = merge_renormalize;
+	int normalize = o->renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -1484,6 +1484,7 @@ void init_merge_options(struct merge_options *o)
 	o->buffer_output = 1;
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
+	o->renormalize = merge_renormalize;
 	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =
diff --git a/merge-recursive.h b/merge-recursive.h
index b831293..c5fbe79 100644
--- a/merge-recursive.h
+++ b/merge-recursive.h
@@ -14,6 +14,7 @@ struct merge_options {
 	} recursive_variant;
 	const char *subtree_shift;
 	unsigned buffer_output : 1;
+	unsigned renormalize : 1;
 	int verbosity;
 	int diff_rename_limit;
 	int merge_rename_limit;

diff --git a/Documentation/technical/api-merge.txt b/Documentation/technical/api-merge.txt
new file mode 100644
index 0000000..01a89d6
--- /dev/null
+++ b/Documentation/technical/api-merge.txt
@@ -0,0 +1,70 @@
+merge API
+=========
+
+The merge API helps a program to reconcile two competing sets of
+improvements to some files (e.g., unregistered changes from the work
+tree versus changes involved in switching to a new branch), reporting
+conflicts if found.  The library called through this API is
+responsible for a few things.
+
+ * determining which trees to merge (recursive ancestor consolidation);
+
+ * lining up corresponding files in the trees to be merged (rename
+   detection, subtree shifting), reporting edge cases like add/add
+   and rename/rename conflicts to the user;
+
+ * performing a three-way merge of corresponding files, taking
+   path-specific merge drivers (specified in `.gitattributes`)
+   into account.
+
+Low-level (single file) merge
+-----------------------------
+
+`ll_merge`::
+
+	Perform a three-way single-file merge in core.  This is
+	a thin wrapper around `xdl_merge` that takes the path and
+	any merge backend specified in `.gitattributes` or
+	`.git/info/attributes` into account.  Returns 0 for a
+	clean merge.
+
+The caller:
+
+1. allocates an mmbuffer_t variable for the result;
+2. allocates and fills variables with the file's original content
+   and two modified versions (using `read_mmfile`, for example);
+3. calls ll_merge();
+4. reads the output from result_buf.ptr and result_buf.size;
+5. releases buffers when finished (free(ancestor.ptr); free(ours.ptr);
+   free(theirs.ptr); free(result_buf.ptr);).
+
+If the modifications do not merge cleanly, `ll_merge` will return a
+nonzero value and `result_buf` will generally include a description of
+the conflict bracketed by markers such as the traditional `<<<<<<<`
+and `>>>>>>>`.
+
+The `ancestor_label`, `our_label`, and `their_label` parameters are
+used to label the different sides of a conflict if the merge driver
+supports this.
+
+The `flag` parameter is a bitfield:
+
+ - The least significant bit indicates whether this is an internal
+   merge to consolidate ancestors for a recursive merge.
+
+ - The next two bits allow local conflicts to be automatically
+   resolved in favor of one side or the other (as in 'git merge-file'
+   `--ours`/`--theirs`/`--union` for 01, 10, and 11, respectively).
+
+Everything else
+---------------
+
+Talk about <merge-recursive.h> and merge_file():
+
+ - merge_trees() to merge with rename detection
+ - merge_recursive() for ancestor consolidation
+ - try_merge_command() for other strategies
+ - conflict format
+ - merge options
+
+(Daniel, Miklos, Stephan, JC)

Documentation/technical/api-merge.txt, ll-merge.c, ll-merge.h, merge-recursive.c

diff --git a/Documentation/technical/api-merge.txt b/Documentation/technical/api-merge.txt
index 01a89d6..a7e050b 100644
--- a/Documentation/technical/api-merge.txt
+++ b/Documentation/technical/api-merge.txt
@@ -49,12 +49,15 @@ supports this.
 
 The `flag` parameter is a bitfield:
 
- - The least significant bit indicates whether this is an internal
-   merge to consolidate ancestors for a recursive merge.
+ - The `LL_OPT_VIRTUAL_ANCESTOR` bit indicates whether this is an
+   internal merge to consolidate ancestors for a recursive merge.
 
- - The next two bits allow local conflicts to be automatically
+ - The `LL_OPT_FAVOR_MASK` bits allow local conflicts to be automatically
    resolved in favor of one side or the other (as in 'git merge-file'
-   `--ours`/`--theirs`/`--union` for 01, 10, and 11, respectively).
+   `--ours`/`--theirs`/`--union`).
+   They can be populated by `create_ll_flag`, whose argument can be
+   `XDL_MERGE_FAVOR_OURS`, `XDL_MERGE_FAVOR_THEIRS`, or
+   `XDL_MERGE_FAVOR_UNION`.
 
 Everything else
 ---------------
diff --git a/ll-merge.c b/ll-merge.c
index 5068fe0..290f764 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -46,7 +46,7 @@ static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
 	 * or common ancestor for an internal merge.  Still return
 	 * "conflicted merge" status.
 	 */
-	mmfile_t *stolen = (flag & 01) ? orig : src1;
+	mmfile_t *stolen = (flag & LL_OPT_VIRTUAL_ANCESTOR) ? orig : src1;
 
 	result->ptr = stolen->ptr;
 	result->size = stolen->size;
@@ -79,7 +79,7 @@ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
 
 	memset(&xmp, 0, sizeof(xmp));
 	xmp.level = XDL_MERGE_ZEALOUS;
-	xmp.favor= (flag >> 1) & 03;
+	xmp.favor = ll_opt_favor(flag);
 	if (git_xmerge_style >= 0)
 		xmp.style = git_xmerge_style;
 	if (marker_size > 0)
@@ -99,7 +99,8 @@ static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 			  int flag, int marker_size)
 {
 	/* Use union favor */
-	flag = (flag & 1) | (XDL_MERGE_FAVOR_UNION << 1);
+	flag = (flag & LL_OPT_VIRTUAL_ANCESTOR) |
+	       create_ll_flag(XDL_MERGE_FAVOR_UNION);
 	return ll_xdl_merge(drv_unused, result, path_unused,
 			    orig, NULL, src1, NULL, src2, NULL,
 			    flag, marker_size);
@@ -342,7 +343,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	const char *ll_driver_name = NULL;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 	const struct ll_merge_driver *driver;
-	int virtual_ancestor = flag & 01;
+	int virtual_ancestor = flag & LL_OPT_VIRTUAL_ANCESTOR;
 
 	if (merge_renormalize) {
 		normalize_file(ancestor, path);
diff --git a/ll-merge.h b/ll-merge.h
index 57754cc..5990271 100644
--- a/ll-merge.h
+++ b/ll-merge.h
@@ -5,6 +5,20 @@
 #ifndef LL_MERGE_H
 #define LL_MERGE_H
 
+#define LL_OPT_VIRTUAL_ANCESTOR	(1 << 0)
+#define LL_OPT_FAVOR_MASK	((1 << 1) | (1 << 2))
+#define LL_OPT_FAVOR_SHIFT 1
+
+static inline int ll_opt_favor(int flag)
+{
+	return (flag & LL_OPT_FAVOR_MASK) >> LL_OPT_FAVOR_SHIFT;
+}
+
+static inline int create_ll_flag(int favor)
+{
+	return ((favor << LL_OPT_FAVOR_SHIFT) & LL_OPT_FAVOR_MASK);
+}
+
 int ll_merge(mmbuffer_t *result_buf,
 	     const char *path,
 	     mmfile_t *ancestor, const char *ancestor_label,
diff --git a/merge-recursive.c b/merge-recursive.c
index 8a49844..c0c9f0c 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -647,7 +647,8 @@ static int merge_3way(struct merge_options *o,
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
-				(!!o->call_depth) | (favor << 1));
+				((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
+				 create_ll_flag(favor)));
 
 	free(name1);
 	free(name2);

builtin/checkout.c, ll-merge.c, ll-merge.h, merge-recursive.c, rerere.c

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 1994be9..a0c00d3 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -150,6 +150,10 @@ static int checkout_merged(int pos, struct checkout *state)
 	read_mmblob(&ours, active_cache[pos+1]->sha1);
 	read_mmblob(&theirs, active_cache[pos+2]->sha1);
 
+	/*
+	 * NEEDSWORK: re-create conflicts from merges with
+	 * merge.renormalize set, too
+	 */
 	status = ll_merge(&result_buf, path, &ancestor, "base",
 			  &ours, "ours", &theirs, "theirs", 0);
 	free(ancestor.ptr);
diff --git a/ll-merge.c b/ll-merge.c
index 290f764..6bb3095 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -99,8 +99,8 @@ static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 			  int flag, int marker_size)
 {
 	/* Use union favor */
-	flag = (flag & LL_OPT_VIRTUAL_ANCESTOR) |
-	       create_ll_flag(XDL_MERGE_FAVOR_UNION);
+	flag &= ~LL_OPT_FAVOR_MASK;
+	flag |= create_ll_flag(XDL_MERGE_FAVOR_UNION);
 	return ll_xdl_merge(drv_unused, result, path_unused,
 			    orig, NULL, src1, NULL, src2, NULL,
 			    flag, marker_size);
@@ -345,7 +345,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	const struct ll_merge_driver *driver;
 	int virtual_ancestor = flag & LL_OPT_VIRTUAL_ANCESTOR;
 
-	if (merge_renormalize) {
+	if (flag & LL_OPT_RENORMALIZE) {
 		normalize_file(ancestor, path);
 		normalize_file(ours, path);
 		normalize_file(theirs, path);
diff --git a/ll-merge.h b/ll-merge.h
index 5990271..ff7ca87 100644
--- a/ll-merge.h
+++ b/ll-merge.h
@@ -8,6 +8,7 @@
 #define LL_OPT_VIRTUAL_ANCESTOR	(1 << 0)
 #define LL_OPT_FAVOR_MASK	((1 << 1) | (1 << 2))
 #define LL_OPT_FAVOR_SHIFT 1
+#define LL_OPT_RENORMALIZE	(1 << 3)
 
 static inline int ll_opt_favor(int flag)
 {
diff --git a/merge-recursive.c b/merge-recursive.c
index c0c9f0c..23f7a4d 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -648,6 +648,7 @@ static int merge_3way(struct merge_options *o,
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
 				((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
+				 (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
 				 create_ll_flag(favor)));
 
 	free(name1);
diff --git a/rerere.c b/rerere.c
index 2197890..9dd4c7e 100644
--- a/rerere.c
+++ b/rerere.c
@@ -319,6 +319,10 @@ static int handle_cache(const char *path, unsigned char *sha1, const char *outpu
 		if (!mmfile[i].ptr && !mmfile[i].size)
 			mmfile[i].ptr = xstrdup("");
 	}
+	/*
+	 * NEEDSWORK: handle conflicts from merges with
+	 * merge.renormalize set, too
+	 */
 	ll_merge(&result, path, &mmfile[0], NULL,
 		 &mmfile[1], "ours",
 		 &mmfile[2], "theirs", 0);
@@ -361,7 +365,7 @@ static int find_conflict(struct string_list *conflict)
 	return 0;
 }
 
-static int merge(const char *name, const char *path)
+static int merge(const char *name, int renormalize, const char *path)
 {
 	int ret;
 	mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
@@ -376,7 +380,8 @@ static int merge(const char *name, const char *path)
 		ret = 1;
 		goto out;
 	}
-	ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
+	ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "",
+			renormalize ? LL_OPT_RENORMALIZE : 0);
 	if (!ret) {
 		FILE *f = fopen(path, "w");
 		if (!f)
@@ -424,7 +429,7 @@ static int update_paths(struct string_list *update)
 	return status;
 }
 
-static int do_plain_rerere(struct string_list *rr, int fd)
+static int do_plain_rerere(struct string_list *rr, int fd, int renormalize)
 {
 	struct string_list conflict = { NULL, 0, 0, 1 };
 	struct string_list update = { NULL, 0, 0, 1 };
@@ -469,7 +474,7 @@ static int do_plain_rerere(struct string_list *rr, int fd)
 		const char *name = (const char *)rr->items[i].util;
 
 		if (has_rerere_resolution(name)) {
-			if (!merge(name, path)) {
+			if (!merge(name, renormalize, path)) {
 				if (rerere_autoupdate)
 					string_list_insert(path, &update);
 				fprintf(stderr,
@@ -553,7 +558,7 @@ int rerere(int flags)
 	fd = setup_rerere(&merge_rr, flags);
 	if (fd < 0)
 		return 0;
-	return do_plain_rerere(&merge_rr, fd);
+	return do_plain_rerere(&merge_rr, fd, merge_renormalize);
 }
 
 static int rerere_forget_one_path(const char *path, struct string_list *rr)

diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index 70856d0..3ed4d1a 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -4,237 +4,292 @@
 #
 
 test_description='git rerere
+
+! [fifth] version1
+ ! [first] first
+  ! [fourth] version1
+   ! [master] initial
+    ! [second] prefer first over second
+     ! [third] version2
+------
+     + [third] version2
++      [fifth] version1
+  +    [fourth] version1
++ +  + [third^] third
+    -  [second] prefer first over second
+ +  +  [first] first
+    +  [second^] second
+++++++ [master] initial
 '
 
 . ./test-lib.sh
 
-test_expect_success 'setup' "
-	cat > a1 <<- EOF &&
+test_expect_success 'setup' '
+	cat >a1 <<-\EOF &&
 	Some title
 	==========
-	Whether 'tis nobler in the mind to suffer
+	Whether '\''tis nobler in the mind to suffer
 	The slings and arrows of outrageous fortune,
 	Or to take arms against a sea of troubles,
 	And by opposing end them? To die: to sleep;
 	No more; and by a sleep to say we end
 	The heart-ache and the thousand natural shocks
-	That flesh is heir to, 'tis a consummation
-	Devoutly to be wish'd.
+	That flesh is heir to, '\''tis a consummation
+	Devoutly to be wish'\''d.
 	EOF
 
 	git add a1 &&
+	test_tick &&
 	git commit -q -a -m initial &&
 
-	git checkout -b first &&
-	cat >> a1 <<- EOF &&
+	cat >>a1 <<-\EOF &&
 	Some title
 	==========
 	To die, to sleep;
-	To sleep: perchance to dream: ay, there's the rub;
+	To sleep: perchance to dream: ay, there'\''s the rub;
 	For in that sleep of death what dreams may come
 	When we have shuffled off this mortal coil,
-	Must give us pause: there's the respect
+	Must give us pause: there'\''s the respect
 	That makes calamity of so long life;
 	EOF
+
+	git checkout -b first &&
+	test_tick &&
 	git commit -q -a -m first &&
 
 	git checkout -b second master &&
 	git show first:a1 |
-	sed -e 's/To die, t/To die! T/' -e 's/Some title/Some Title/' > a1 &&
-	echo '* END *' >>a1 &&
+	sed -e "s/To die, t/To die! T/" -e "s/Some title/Some Title/" >a1 &&
+	echo "* END *" >>a1 &&
+	test_tick &&
 	git commit -q -a -m second
-"
+'
 
 test_expect_success 'nothing recorded without rerere' '
-	(rm -rf .git/rr-cache; git config rerere.enabled false) &&
+	rm -rf .git/rr-cache &&
+	git config rerere.enabled false &&
 	test_must_fail git merge first &&
 	! test -d .git/rr-cache
 '
 
-# activate rerere, old style
-test_expect_success 'conflicting merge' '
+test_expect_success 'activate rerere, old style (conflicting merge)' '
 	git reset --hard &&
 	mkdir .git/rr-cache &&
-	git config --unset rerere.enabled &&
-	test_must_fail git merge first
-'
+	test_might_fail git config --unset rerere.enabled &&
+	test_must_fail git merge first &&
 
-sha1=$(perl -pe 's/	.*//' .git/MERGE_RR)
-rr=.git/rr-cache/$sha1
-test_expect_success 'recorded preimage' "grep ^=======$ $rr/preimage"
+	sha1=$(perl -pe "s/	.*//" .git/MERGE_RR) &&
+	rr=.git/rr-cache/$sha1 &&
+	grep "^=======\$" $rr/preimage &&
+	! test -f $rr/postimage &&
+	! test -f $rr/thisimage
+'
 
 test_expect_success 'rerere.enabled works, too' '
 	rm -rf .git/rr-cache &&
 	git config rerere.enabled true &&
 	git reset --hard &&
 	test_must_fail git merge first &&
+
+	sha1=$(perl -pe "s/	.*//" .git/MERGE_RR) &&
+	rr=.git/rr-cache/$sha1 &&
 	grep ^=======$ $rr/preimage
 '
 
-test_expect_success 'no postimage or thisimage yet' \
-	"test ! -f $rr/postimage -a ! -f $rr/thisimage"
+test_expect_success 'set up rr-cache' '
+	rm -rf .git/rr-cache &&
+	git config rerere.enabled true &&
+	git reset --hard &&
+	test_must_fail git merge first &&
+	sha1=$(perl -pe "s/	.*//" .git/MERGE_RR) &&
+	rr=.git/rr-cache/$sha1
+'
 
-test_expect_success 'preimage has right number of lines' '
+test_expect_success 'rr-cache looks sane' '
+	# no postimage or thisimage yet
+	! test -f $rr/postimage &&
+	! test -f $rr/thisimage &&
 
+	# preimage has right number of lines
 	cnt=$(sed -ne "/^<<<<<<</,/^>>>>>>>/p" $rr/preimage | wc -l) &&
+	echo $cnt &&
 	test $cnt = 13
-
 '
 
-git show first:a1 > a1
-
-cat > expect << EOF
---- a/a1
-+++ b/a1
-@@ -1,4 +1,4 @@
--Some Title
-+Some title
- ==========
- Whether 'tis nobler in the mind to suffer
- The slings and arrows of outrageous fortune,
-@@ -8,21 +8,11 @@
- The heart-ache and the thousand natural shocks
- That flesh is heir to, 'tis a consummation
- Devoutly to be wish'd.
--<<<<<<<
--Some Title
--==========
--To die! To sleep;
--=======
- Some title
- ==========
- To die, to sleep;
-->>>>>>>
- To sleep: perchance to dream: ay, there's the rub;
- For in that sleep of death what dreams may come
- When we have shuffled off this mortal coil,
- Must give us pause: there's the respect
- That makes calamity of so long life;
--<<<<<<<
--=======
--* END *
-->>>>>>>
-EOF
-git rerere diff > out
-
-test_expect_success 'rerere diff' 'test_cmp expect out'
-
-cat > expect << EOF
-a1
-EOF
-
-git rerere status > out
+test_expect_success 'rerere diff' '
+	git show first:a1 >a1 &&
+	cat >expect <<-\EOF &&
+	--- a/a1
+	+++ b/a1
+	@@ -1,4 +1,4 @@
+	-Some Title
+	+Some title
+	 ==========
+	 Whether '\''tis nobler in the mind to suffer
+	 The slings and arrows of outrageous fortune,
+	@@ -8,21 +8,11 @@
+	 The heart-ache and the thousand natural shocks
+	 That flesh is heir to, '\''tis a consummation
+	 Devoutly to be wish'\''d.
+	-<<<<<<<
+	-Some Title
+	-==========
+	-To die! To sleep;
+	-=======
+	 Some title
+	 ==========
+	 To die, to sleep;
+	->>>>>>>
+	 To sleep: perchance to dream: ay, there'\''s the rub;
+	 For in that sleep of death what dreams may come
+	 When we have shuffled off this mortal coil,
+	 Must give us pause: there'\''s the respect
+	 That makes calamity of so long life;
+	-<<<<<<<
+	-=======
+	-* END *
+	->>>>>>>
+	EOF
+	git rerere diff >out &&
+	test_cmp expect out
+'
 
-test_expect_success 'rerere status' 'test_cmp expect out'
+test_expect_success 'rerere status' '
+	echo a1 >expect &&
+	git rerere status >out &&
+	test_cmp expect out
+'
 
-test_expect_success 'commit succeeds' \
-	"git commit -q -a -m 'prefer first over second'"
+test_expect_success 'first postimage wins' '
+	git show first:a1 | sed "s/To die: t/To die! T/" >expect &&
 
-test_expect_success 'recorded postimage' "test -f $rr/postimage"
+	git commit -q -a -m "prefer first over second" &&
+	test -f $rr/postimage &&
 
-test_expect_success 'another conflicting merge' '
 	git checkout -b third master &&
-	git show second^:a1 | sed "s/To die: t/To die! T/" > a1 &&
+	git show second^:a1 | sed "s/To die: t/To die! T/" >a1 &&
 	git commit -q -a -m third &&
-	test_must_fail git pull . first
-'
-
-git show first:a1 | sed 's/To die: t/To die! T/' > expect
-test_expect_success 'rerere kicked in' "! grep ^=======$ a1"
-
-test_expect_success 'rerere prefers first change' 'test_cmp a1 expect'
-
-rm $rr/postimage
-echo "$sha1	a1" | perl -pe 'y/\012/\000/' > .git/MERGE_RR
-
-test_expect_success 'rerere clear' 'git rerere clear'
-
-test_expect_success 'clear removed the directory' "test ! -d $rr"
 
-mkdir $rr
-echo Hello > $rr/preimage
-echo World > $rr/postimage
-
-sha2=4000000000000000000000000000000000000000
-rr2=.git/rr-cache/$sha2
-mkdir $rr2
-echo Hello > $rr2/preimage
+	test_must_fail git pull . first &&
+	# rerere kicked in
+	! grep "^=======\$" a1 &&
+	test_cmp expect a1
+'
 
-almost_15_days_ago=$((60-15*86400))
-just_over_15_days_ago=$((-1-15*86400))
-almost_60_days_ago=$((60-60*86400))
-just_over_60_days_ago=$((-1-60*86400))
+test_expect_success 'rerere clear' '
+	rm $rr/postimage &&
+	echo "$sha1	a1" | perl -pe "y/\012/\000/" >.git/MERGE_RR &&
+	git rerere clear &&
+	! test -d $rr
+'
 
-test-chmtime =$almost_60_days_ago $rr/preimage
-test-chmtime =$almost_15_days_ago $rr2/preimage
+test_expect_success 'set up for garbage collection tests' '
+	mkdir -p $rr &&
+	echo Hello >$rr/preimage &&
+	echo World >$rr/postimage &&
 
-test_expect_success 'garbage collection (part1)' 'git rerere gc'
+	sha2=4000000000000000000000000000000000000000 &&
+	rr2=.git/rr-cache/$sha2 &&
+	mkdir $rr2 &&
+	echo Hello >$rr2/preimage &&
 
-test_expect_success 'young records still live' \
-	"test -f $rr/preimage && test -f $rr2/preimage"
+	almost_15_days_ago=$((60-15*86400)) &&
+	just_over_15_days_ago=$((-1-15*86400)) &&
+	almost_60_days_ago=$((60-60*86400)) &&
+	just_over_60_days_ago=$((-1-60*86400)) &&
 
-test-chmtime =$just_over_60_days_ago $rr/preimage
-test-chmtime =$just_over_15_days_ago $rr2/preimage
+	test-chmtime =$almost_60_days_ago $rr/preimage &&
+	test-chmtime =$almost_15_days_ago $rr2/preimage
+'
 
-test_expect_success 'garbage collection (part2)' 'git rerere gc'
+test_expect_success 'garbage collection preserves young records' '
+	git rerere gc &&
+	test -f $rr/preimage &&
+	test -f $rr2/preimage
+'
 
-test_expect_success 'old records rest in peace' \
-	"test ! -f $rr/preimage && test ! -f $rr2/preimage"
+test_expect_success 'old records rest in peace' '
+	test-chmtime =$just_over_60_days_ago $rr/preimage &&
+	test-chmtime =$just_over_15_days_ago $rr2/preimage &&
+	git rerere gc &&
+	! test -f $rr/preimage &&
+	! test -f $rr2/preimage
+'
 
-test_expect_success 'file2 added differently in two branches' '
+test_expect_success 'setup: file2 added differently in two branches' '
 	git reset --hard &&
+
 	git checkout -b fourth &&
-	echo Hallo > file2 &&
+	echo Hallo >file2 &&
 	git add file2 &&
+	test_tick &&
 	git commit -m version1 &&
+
 	git checkout third &&
-	echo Bello > file2 &&
+	echo Bello >file2 &&
 	git add file2 &&
+	test_tick &&
 	git commit -m version2 &&
+
 	test_must_fail git merge fourth &&
-	echo Cello > file2 &&
+	echo Cello >file2 &&
 	git add file2 &&
 	git commit -m resolution
 '
 
 test_expect_success 'resolution was recorded properly' '
+	echo Cello >expected &&
+
 	git reset --hard HEAD~2 &&
 	git checkout -b fifth &&
-	echo Hallo > file3 &&
+
+	echo Hallo >file3 &&
 	git add file3 &&
+	test_tick &&
 	git commit -m version1 &&
+
 	git checkout third &&
-	echo Bello > file3 &&
+	echo Bello >file3 &&
 	git add file3 &&
+	test_tick &&
 	git commit -m version2 &&
 	git tag version2 &&
+
 	test_must_fail git merge fifth &&
-	test Cello = "$(cat file3)" &&
-	test 0 != $(git ls-files -u | wc -l)
+	test_cmp expected file3 &&
+	test_must_fail git update-index --refresh
 '
 
 test_expect_success 'rerere.autoupdate' '
-	git config rerere.autoupdate true
+	git config rerere.autoupdate true &&
 	git reset --hard &&
 	git checkout version2 &&
 	test_must_fail git merge fifth &&
-	test 0 = $(git ls-files -u | wc -l)
+	git update-index --refresh
 '
 
 test_expect_success 'merge --rerere-autoupdate' '
-	git config --unset rerere.autoupdate
+	test_might_fail git config --unset rerere.autoupdate &&
 	git reset --hard &&
 	git checkout version2 &&
 	test_must_fail git merge --rerere-autoupdate fifth &&
-	test 0 = $(git ls-files -u | wc -l)
+	git update-index --refresh
 '
 
 test_expect_success 'merge --no-rerere-autoupdate' '
-	git config rerere.autoupdate true
+	headblob=$(git rev-parse version2:file3) &&
+	mergeblob=$(git rev-parse fifth:file3) &&
+	cat >expected <<-EOF &&
+	100644 $headblob 2	file3
+	100644 $mergeblob 3	file3
+	EOF
+
+	git config rerere.autoupdate true &&
 	git reset --hard &&
 	git checkout version2 &&
 	test_must_fail git merge --no-rerere-autoupdate fifth &&
-	test 2 = $(git ls-files -u | wc -l)
+	git ls-files -u >actual &&
+	test_cmp expected actual
 '
 
 test_done

builtin/rerere.c, t/t4200-rerere.sh

diff --git a/builtin/rerere.c b/builtin/rerere.c
index 0048f9e..295fe75 100644
--- a/builtin/rerere.c
+++ b/builtin/rerere.c
@@ -1,13 +1,16 @@
 #include "builtin.h"
 #include "cache.h"
 #include "dir.h"
+#include "parse-options.h"
 #include "string-list.h"
 #include "rerere.h"
 #include "xdiff/xdiff.h"
 #include "xdiff-interface.h"
 
-static const char git_rerere_usage[] =
-"git rerere [clear | status | diff | gc]";
+static const char * const rerere_usage[] = {
+	"git rerere [clear | status | diff | gc]",
+	NULL,
+};
 
 /* these values are days */
 static int cutoff_noresolve = 15;
@@ -103,25 +106,26 @@ static int diff_two(const char *file1, const char *label1,
 int cmd_rerere(int argc, const char **argv, const char *prefix)
 {
 	struct string_list merge_rr = { NULL, 0, 0, 1 };
-	int i, fd, flags = 0;
-
-	if (2 < argc) {
-		if (!strcmp(argv[1], "-h"))
-			usage(git_rerere_usage);
-		if (!strcmp(argv[1], "--rerere-autoupdate"))
-			flags = RERERE_AUTOUPDATE;
-		else if (!strcmp(argv[1], "--no-rerere-autoupdate"))
-			flags = RERERE_NOAUTOUPDATE;
-		if (flags) {
-			argc--;
-			argv++;
-		}
-	}
-	if (argc < 2)
+	int i, fd, autoupdate = -1, flags = 0;
+
+	struct option options[] = {
+		OPT_SET_INT(0, "rerere-autoupdate", &autoupdate,
+			"register clean resolutions in index", 1),
+		OPT_END(),
+	};
+
+	argc = parse_options(argc, argv, prefix, options, rerere_usage, 0);
+
+	if (autoupdate == 1)
+		flags = RERERE_AUTOUPDATE;
+	if (autoupdate == 0)
+		flags = RERERE_NOAUTOUPDATE;
+
+	if (argc < 1)
 		return rerere(flags);
 
-	if (!strcmp(argv[1], "forget")) {
-		const char **pathspec = get_pathspec(prefix, argv + 2);
+	if (!strcmp(argv[0], "forget")) {
+		const char **pathspec = get_pathspec(prefix, argv + 1);
 		return rerere_forget(pathspec);
 	}
 
@@ -129,26 +133,26 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
 	if (fd < 0)
 		return 0;
 
-	if (!strcmp(argv[1], "clear")) {
+	if (!strcmp(argv[0], "clear")) {
 		for (i = 0; i < merge_rr.nr; i++) {
 			const char *name = (const char *)merge_rr.items[i].util;
 			if (!has_rerere_resolution(name))
 				unlink_rr_item(name);
 		}
 		unlink_or_warn(git_path("rr-cache/MERGE_RR"));
-	} else if (!strcmp(argv[1], "gc"))
+	} else if (!strcmp(argv[0], "gc"))
 		garbage_collect(&merge_rr);
-	else if (!strcmp(argv[1], "status"))
+	else if (!strcmp(argv[0], "status"))
 		for (i = 0; i < merge_rr.nr; i++)
 			printf("%s\n", merge_rr.items[i].string);
-	else if (!strcmp(argv[1], "diff"))
+	else if (!strcmp(argv[0], "diff"))
 		for (i = 0; i < merge_rr.nr; i++) {
 			const char *path = merge_rr.items[i].string;
 			const char *name = (const char *)merge_rr.items[i].util;
 			diff_two(rerere_path(name, "preimage"), path, path, path);
 		}
 	else
-		usage(git_rerere_usage);
+		usage_with_options(rerere_usage, options);
 
 	string_list_clear(&merge_rr, 1);
 	return 0;
diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh
index 3ed4d1a..876f09a 100755
--- a/t/t4200-rerere.sh
+++ b/t/t4200-rerere.sh
@@ -292,4 +292,95 @@ test_expect_success 'merge --no-rerere-autoupdate' '
 	test_cmp expected actual
 '
 
+test_expect_success 'set up an unresolved merge' '
+	headblob=$(git rev-parse version2:file3) &&
+	mergeblob=$(git rev-parse fifth:file3) &&
+	cat >expected.unresolved <<-EOF &&
+	100644 $headblob 2	file3
+	100644 $mergeblob 3	file3
+	EOF
+
+	test_might_fail git config --unset rerere.autoupdate &&
+	git reset --hard &&
+	git checkout version2 &&
+	fifth=$(git rev-parse fifth) &&
+	echo "$fifth		branch 'fifth' of ." |
+	git fmt-merge-msg >msg &&
+	ancestor=$(git merge-base version2 fifth) &&
+	test_must_fail git merge-recursive "$ancestor" -- HEAD fifth &&
+
+	git ls-files --stage >failedmerge &&
+	cp file3 file3.conflict &&
+
+	git ls-files -u >actual &&
+	test_cmp expected.unresolved actual
+'
+
+test_expect_success 'explicit rerere' '
+	test_might_fail git config --unset rerere.autoupdate &&
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	test_must_fail git update-index --refresh -q &&
+
+	git rerere &&
+	git ls-files -u >actual &&
+	test_cmp expected.unresolved actual
+'
+
+test_expect_success 'explicit rerere with autoupdate' '
+	git config rerere.autoupdate true &&
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	test_must_fail git update-index --refresh -q &&
+
+	git rerere &&
+	git update-index --refresh
+'
+
+test_expect_success 'explicit rerere --rerere-autoupdate overrides' '
+	git config rerere.autoupdate false &&
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	git rerere &&
+	git ls-files -u >actual1 &&
+
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	git rerere --rerere-autoupdate &&
+	git update-index --refresh &&
+
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	git rerere --rerere-autoupdate --no-rerere-autoupdate &&
+	git ls-files -u >actual2 &&
+
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	git rerere --rerere-autoupdate --no-rerere-autoupdate --rerere-autoupdate &&
+	git update-index --refresh &&
+
+	test_cmp expected.unresolved actual1 &&
+	test_cmp expected.unresolved actual2
+'
+
+test_expect_success 'rerere --no-no-rerere-autoupdate' '
+	git rm -fr --cached . &&
+	git update-index --index-info <failedmerge &&
+	cp file3.conflict file3 &&
+	test_must_fail git rerere --no-no-rerere-autoupdate 2>err &&
+	grep [Uu]sage err &&
+	test_must_fail git update-index --refresh
+'
+
+test_expect_success 'rerere -h' '
+	test_must_fail git rerere -h >help &&
+	grep [Uu]sage help
+'
+
 test_done

diff --git a/rerere.c b/rerere.c
index 9dd4c7e..e40af0d 100644
--- a/rerere.c
+++ b/rerere.c
@@ -365,7 +365,7 @@ static int find_conflict(struct string_list *conflict)
 	return 0;
 }
 
-static int merge(const char *name, int renormalize, const char *path)
+static int merge(const char *name, const char *path)
 {
 	int ret;
 	mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0};
@@ -380,8 +380,7 @@ static int merge(const char *name, int renormalize, const char *path)
 		ret = 1;
 		goto out;
 	}
-	ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "",
-			renormalize ? LL_OPT_RENORMALIZE : 0);
+	ret = ll_merge(&result, path, &base, NULL, &cur, "", &other, "", 0);
 	if (!ret) {
 		FILE *f = fopen(path, "w");
 		if (!f)
@@ -429,7 +428,7 @@ static int update_paths(struct string_list *update)
 	return status;
 }
 
-static int do_plain_rerere(struct string_list *rr, int fd, int renormalize)
+static int do_plain_rerere(struct string_list *rr, int fd)
 {
 	struct string_list conflict = { NULL, 0, 0, 1 };
 	struct string_list update = { NULL, 0, 0, 1 };
@@ -474,7 +473,7 @@ static int do_plain_rerere(struct string_list *rr, int fd, int renormalize)
 		const char *name = (const char *)rr->items[i].util;
 
 		if (has_rerere_resolution(name)) {
-			if (!merge(name, renormalize, path)) {
+			if (!merge(name, path)) {
 				if (rerere_autoupdate)
 					string_list_insert(path, &update);
 				fprintf(stderr,
@@ -558,7 +557,7 @@ int rerere(int flags)
 	fd = setup_rerere(&merge_rr, flags);
 	if (fd < 0)
 		return 0;
-	return do_plain_rerere(&merge_rr, fd, merge_renormalize);
+	return do_plain_rerere(&merge_rr, fd);
 }
 
 static int rerere_forget_one_path(const char *path, struct string_list *rr)

Documentation/merge-strategies.txt, builtin/checkout.c, builtin/merge-recursive.c, builtin/merge.c, builtin/revert.c, cache.h, environment.c, merge-recursive.c

diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index a5bc1db..049313d 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -40,6 +40,18 @@ the other tree did, declaring 'our' history contains all that happened in it.
 theirs;;
 	This is opposite of 'ours'.
 
+renormalize;;
+	This runs a virtual check-out and check-in of all three stages
+	of a file when resolving a three-way merge.  This option is
+	meant to be used when merging branches with different clean
+	filters or end-of-line normalization rules.  See "Merging
+	branches with differing checkin/checkout attributes" in
+	linkgit:gitattributes[5] for details.
+
+no-renormalize;;
+	Disables the `renormalize` option.  This overrides the
+	`merge.renormalize` configuration variable.
+
 subtree[=path];;
 	This option is a more advanced form of 'subtree' strategy, where
 	the strategy makes a guess on how two trees must be shifted to
diff --git a/builtin/checkout.c b/builtin/checkout.c
index a0c00d3..24b67d5 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -437,6 +437,13 @@ static int merge_working_tree(struct checkout_opts *opts,
 			 */
 
 			add_files_to_cache(NULL, NULL, 0);
+			/*
+			 * NEEDSWORK: carrying over local changes
+			 * when branches have different end-of-line
+			 * normalization (or clean+smudge rules) is
+			 * a pain; plumb in an option to set
+			 * o.renormalize?
+			 */
 			init_merge_options(&o);
 			o.verbosity = 0;
 			work = write_tree_from_memory(&o);
diff --git a/builtin/merge-recursive.c b/builtin/merge-recursive.c
index d8875d5..c2d4677 100644
--- a/builtin/merge-recursive.c
+++ b/builtin/merge-recursive.c
@@ -45,6 +45,10 @@ int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
 				o.subtree_shift = "";
 			else if (!prefixcmp(arg+2, "subtree="))
 				o.subtree_shift = arg + 10;
+			else if (!strcmp(arg+2, "renormalize"))
+				o.renormalize = 1;
+			else if (!strcmp(arg+2, "no-renormalize"))
+				o.renormalize = 0;
 			else
 				die("Unknown option %s", arg);
 			continue;
diff --git a/builtin/merge.c b/builtin/merge.c
index b836e9c..037cd47 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -54,6 +54,7 @@ static size_t use_strategies_nr, use_strategies_alloc;
 static const char **xopts;
 static size_t xopts_nr, xopts_alloc;
 static const char *branch;
+static int option_renormalize;
 static int verbosity;
 static int allow_rerere_auto;
 
@@ -503,9 +504,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 		return git_config_string(&pull_octopus, k, v);
 	else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
 		option_log = git_config_bool(k, v);
-	else if (!strcmp(k, "merge.renormalize")) {
-		merge_renormalize = git_config_bool(k, v);
-	}
+	else if (!strcmp(k, "merge.renormalize"))
+		option_renormalize = git_config_bool(k, v);
 	return git_diff_ui_config(k, v, cb);
 }
 
@@ -627,6 +627,11 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		if (!strcmp(strategy, "subtree"))
 			o.subtree_shift = "";
 
+		o.renormalize = option_renormalize;
+
+		/*
+		 * NEEDSWORK: merge with table in builtin/merge-recursive
+		 */
 		for (x = 0; x < xopts_nr; x++) {
 			if (!strcmp(xopts[x], "ours"))
 				o.recursive_variant = MERGE_RECURSIVE_OURS;
@@ -636,6 +641,10 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 				o.subtree_shift = "";
 			else if (!prefixcmp(xopts[x], "subtree="))
 				o.subtree_shift = xopts[x]+8;
+			else if (!strcmp(xopts[x], "renormalize"))
+				o.renormalize = 1;
+			else if (!strcmp(xopts[x], "no-renormalize"))
+				o.renormalize = 0;
 			else
 				die("Unknown option for merge-recursive: -X%s", xopts[x]);
 		}
@@ -819,7 +828,7 @@ static int finish_automerge(struct commit_list *common,
 	return 0;
 }
 
-static int suggest_conflicts(void)
+static int suggest_conflicts(int renormalizing)
 {
 	FILE *fp;
 	int pos;
@@ -1304,5 +1313,5 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			"stopped before committing as requested\n");
 		return 0;
 	} else
-		return suggest_conflicts();
+		return suggest_conflicts(option_renormalize);
 }
diff --git a/builtin/revert.c b/builtin/revert.c
index 853e9e4..1113253 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -318,6 +318,13 @@ static void do_recursive_merge(struct commit *base, struct commit *next,
 	index_fd = hold_locked_index(&index_lock, 1);
 
 	read_cache();
+
+	/*
+	 * NEEDSWORK: cherry-picking between branches with
+	 * different end-of-line normalization is a pain;
+	 * plumb in an option to set o.renormalize?
+	 * (or better: arbitrary -X options)
+	 */
 	init_merge_options(&o);
 	o.ancestor = base ? base_label : "(empty tree)";
 	o.branch1 = "HEAD";
diff --git a/cache.h b/cache.h
index ed73da8..aa725b0 100644
--- a/cache.h
+++ b/cache.h
@@ -551,7 +551,6 @@ extern int read_replace_refs;
 extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
-extern int merge_renormalize;
 
 enum safe_crlf {
 	SAFE_CRLF_FALSE = 0,
diff --git a/environment.c b/environment.c
index 81a3682..83d38d3 100644
--- a/environment.c
+++ b/environment.c
@@ -53,7 +53,6 @@ enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 char *notes_ref_name;
 int grafts_replace_parents = 1;
 int core_apply_sparse_checkout;
-int merge_renormalize;
 
 /* Parallel index stat data preload? */
 int core_preload_index = 0;
diff --git a/merge-recursive.c b/merge-recursive.c
index 23f7a4d..762b549 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1486,7 +1486,7 @@ void init_merge_options(struct merge_options *o)
 	o->buffer_output = 1;
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
-	o->renormalize = merge_renormalize;
+	o->renormalize = 0;
 	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =

Documentation/merge-strategies.txt, builtin/checkout.c, builtin/merge-recursive.c, builtin/merge.c, builtin/revert.c, cache.h, environment.c, merge-recursive.c

diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt
index a5bc1db..350c3c7 100644
--- a/Documentation/merge-strategies.txt
+++ b/Documentation/merge-strategies.txt
@@ -40,6 +40,14 @@ the other tree did, declaring 'our' history contains all that happened in it.
 theirs;;
 	This is opposite of 'ours'.
 
+renormalize;;
+	This runs a virtual check-out and check-in of all three stages
+	of a file when resolving a three-way merge.  This option is
+	meant to be used when merging branches with different clean
+	filters or end-of-line normalization rules.  See "Merging
+	branches with differing checkin/checkout attributes" in
+	linkgit:gitattributes[5] for details.
+
 subtree[=path];;
 	This option is a more advanced form of 'subtree' strategy, where
 	the strategy makes a guess on how two trees must be shifted to
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 5a7ae03..00fd4cd 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -437,6 +437,13 @@ static int merge_working_tree(struct checkout_opts *opts,
 			 */
 
 			add_files_to_cache(NULL, NULL, 0);
+			/*
+			 * NEEDSWORK: carrying over local changes
+			 * when branches have different end-of-line
+			 * normalization (or clean+smudge rules) is
+			 * a pain; plumb in an option to set
+			 * o.renormalize?
+			 */
 			init_merge_options(&o);
 			o.verbosity = 0;
 			work = write_tree_from_memory(&o);
diff --git a/builtin/merge-recursive.c b/builtin/merge-recursive.c
index d8875d5..2cc84d9 100644
--- a/builtin/merge-recursive.c
+++ b/builtin/merge-recursive.c
@@ -45,6 +45,8 @@ int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
 				o.subtree_shift = "";
 			else if (!prefixcmp(arg+2, "subtree="))
 				o.subtree_shift = arg + 10;
+			else if (!strcmp(arg+2, "renormalize"))
+				o.renormalize = 1;
 			else
 				die("Unknown option %s", arg);
 			continue;
diff --git a/builtin/merge.c b/builtin/merge.c
index 823b76b..ad0aa5a 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -54,6 +54,7 @@ static size_t use_strategies_nr, use_strategies_alloc;
 static const char **xopts;
 static size_t xopts_nr, xopts_alloc;
 static const char *branch;
+static int option_renormalize;
 static int verbosity;
 static int allow_rerere_auto;
 
@@ -503,9 +504,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 		return git_config_string(&pull_octopus, k, v);
 	else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
 		option_log = git_config_bool(k, v);
-	else if (!strcmp(k, "merge.renormalize")) {
-		merge_renormalize = git_config_bool(k, v);
-	}
+	else if (!strcmp(k, "merge.renormalize"))
+		option_renormalize = git_config_bool(k, v);
 	return git_diff_ui_config(k, v, cb);
 }
 
@@ -627,6 +627,11 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		if (!strcmp(strategy, "subtree"))
 			o.subtree_shift = "";
 
+		o.renormalize = option_renormalize;
+
+		/*
+		 * NEEDSWORK: merge with table in builtin/merge-recursive
+		 */
 		for (x = 0; x < xopts_nr; x++) {
 			if (!strcmp(xopts[x], "ours"))
 				o.recursive_variant = MERGE_RECURSIVE_OURS;
@@ -636,6 +641,8 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 				o.subtree_shift = "";
 			else if (!prefixcmp(xopts[x], "subtree="))
 				o.subtree_shift = xopts[x]+8;
+			else if (!strcmp(xopts[x], "renormalize"))
+				o.renormalize = 1;
 			else
 				die("Unknown option for merge-recursive: -X%s", xopts[x]);
 		}
@@ -819,7 +826,7 @@ static int finish_automerge(struct commit_list *common,
 	return 0;
 }
 
-static int suggest_conflicts(void)
+static int suggest_conflicts(int renormalizing)
 {
 	FILE *fp;
 	int pos, flag;
@@ -842,7 +849,7 @@ static int suggest_conflicts(void)
 	}
 	fclose(fp);
 	flag = allow_rerere_auto;
-	if (merge_renormalize)
+	if (renormalizing)
 		flag |= RERERE_RENORMALIZE;
 	rerere(flag);
 	printf("Automatic merge failed; "
@@ -1307,5 +1314,5 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 			"stopped before committing as requested\n");
 		return 0;
 	} else
-		return suggest_conflicts();
+		return suggest_conflicts(option_renormalize);
 }
diff --git a/builtin/revert.c b/builtin/revert.c
index c694801..1999252 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -318,6 +318,13 @@ static void do_recursive_merge(struct commit *base, struct commit *next,
 	index_fd = hold_locked_index(&index_lock, 1);
 
 	read_cache();
+
+	/*
+	 * NEEDSWORK: cherry-picking between branches with
+	 * different end-of-line normalization is a pain;
+	 * plumb in an option to set o.renormalize?
+	 * (or better: arbitrary -X options)
+	 */
 	init_merge_options(&o);
 	o.ancestor = base ? base_label : "(empty tree)";
 	o.branch1 = "HEAD";
diff --git a/cache.h b/cache.h
index ed73da8..aa725b0 100644
--- a/cache.h
+++ b/cache.h
@@ -551,7 +551,6 @@ extern int read_replace_refs;
 extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
-extern int merge_renormalize;
 
 enum safe_crlf {
 	SAFE_CRLF_FALSE = 0,
diff --git a/environment.c b/environment.c
index 81a3682..83d38d3 100644
--- a/environment.c
+++ b/environment.c
@@ -53,7 +53,6 @@ enum object_creation_mode object_creation_mode = OBJECT_CREATION_MODE;
 char *notes_ref_name;
 int grafts_replace_parents = 1;
 int core_apply_sparse_checkout;
-int merge_renormalize;
 
 /* Parallel index stat data preload? */
 int core_preload_index = 0;
diff --git a/merge-recursive.c b/merge-recursive.c
index 4838939..73f2768 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1485,7 +1485,7 @@ void init_merge_options(struct merge_options *o)
 	o->buffer_output = 1;
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
-	o->renormalize = merge_renormalize;
+	o->renormalize = 0;
 	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =