patch, 3 partsresend/cleanup: Fix up subproject support

diff --git a/read-cache.c b/read-cache.c
index 4040fac..72d7d7c 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -123,9 +123,9 @@ static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 		if (ce_compare_link(ce, xsize_t(st->st_size)))
 			return DATA_CHANGED;
 		break;
-	case S_IFDIRLNK:
-		/* No need to do anything, we did the exact compare in "match_stat_basic" */
-		break;
+	case S_IFDIR:
+		if (S_ISDIRLNK(ntohl(ce->ce_mode)))
+			return 0;
 	default:
 		return TYPE_CHANGED;
 	}
@@ -156,7 +156,7 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 			changed |= TYPE_CHANGED;
 		else if (ce_compare_gitlink(ce))
 			changed |= DATA_CHANGED;
-		break;
+		return changed;
 	default:
 		die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
 	}

diff --git a/list-objects.c b/list-objects.c
index 2ba2c95..310f8d3 100644
--- a/list-objects.c
+++ b/list-objects.c
@@ -25,6 +25,37 @@ static void process_blob(struct rev_info *revs,
 	add_object(obj, p, path, name);
 }
 
+/*
+ * Processing a gitlink entry currently does nothing, since
+ * we do not recurse into the subproject.
+ *
+ * We *could* eventually add a flag that actually does that,
+ * which would involve:
+ *  - is the subproject actually checked out?
+ *  - if so, see if the subproject has already been added
+ *    to the alternates list, and add it if not.
+ *  - process the commit (or tag) the gitlink points to
+ *    recursively.
+ *
+ * However, it's unclear whether there is really ever any
+ * reason to see superprojects and subprojects as such a
+ * "unified" object pool (potentially resulting in a totally
+ * humongous pack - avoiding which was the whole point of
+ * having gitlinks in the first place!).
+ *
+ * So for now, there is just a note that we *could* follow
+ * the link, and how to do it. Whether it necessarily makes
+ * any sense what-so-ever to ever do that is another issue.
+ */
+static void process_gitlink(struct rev_info *revs,
+			    const unsigned char *sha1,
+			    struct object_array *p,
+			    struct name_path *path,
+			    const char *name)
+{
+	/* Nothing to do */
+}
+
 static void process_tree(struct rev_info *revs,
 			 struct tree *tree,
 			 struct object_array *p,
@@ -56,6 +87,9 @@ static void process_tree(struct rev_info *revs,
 			process_tree(revs,
 				     lookup_tree(entry.sha1),
 				     p, &me, entry.path);
+		else if (S_ISDIRLNK(entry.mode))
+			process_gitlink(revs, entry.sha1,
+					p, &me, entry.path);
 		else
 			process_blob(revs,
 				     lookup_blob(entry.sha1),

diff --git a/entry.c b/entry.c
index d72f811..50ffae4 100644
--- a/entry.c
+++ b/entry.c
@@ -62,26 +62,33 @@ static int create_file(const char *path, unsigned int mode)
 	return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
 }
 
+static void *read_blob_entry(struct cache_entry *ce, const char *path, unsigned long *size)
+{
+	enum object_type type;
+	void *new = read_sha1_file(ce->sha1, &type, size);
+
+	if (new) {
+		if (type == OBJ_BLOB)
+			return new;
+		free(new);
+	}
+	return NULL;
+}
+
 static int write_entry(struct cache_entry *ce, char *path, struct checkout *state, int to_tempfile)
 {
 	int fd;
-	void *new;
-	unsigned long size;
 	long wrote;
-	enum object_type type;
 
-	new = read_sha1_file(ce->sha1, &type, &size);
-	if (!new || type != OBJ_BLOB) {
-		if (new)
-			free(new);
-		return error("git-checkout-index: unable to read sha1 file of %s (%s)",
-			path, sha1_to_hex(ce->sha1));
-	}
 	switch (ntohl(ce->ce_mode) & S_IFMT) {
-		char *buf;
-		unsigned long nsize;
+		char *buf, *new;
+		unsigned long size, nsize;
 
 	case S_IFREG:
+		new = read_blob_entry(ce, path, &size);
+		if (!new)
+			return error("git-checkout-index: unable to read sha1 file of %s (%s)",
+				path, sha1_to_hex(ce->sha1));
 		if (to_tempfile) {
 			strcpy(path, ".merge_file_XXXXXX");
 			fd = mkstemp(path);
@@ -111,6 +118,10 @@ static int write_entry(struct cache_entry *ce, char *path, struct checkout *stat
 			return error("git-checkout-index: unable to write file %s", path);
 		break;
 	case S_IFLNK:
+		new = read_blob_entry(ce, path, &size);
+		if (!new)
+			return error("git-checkout-index: unable to read sha1 file of %s (%s)",
+				path, sha1_to_hex(ce->sha1));
 		if (to_tempfile || !has_symlinks) {
 			if (to_tempfile) {
 				strcpy(path, ".merge_link_XXXXXX");
@@ -136,8 +147,13 @@ static int write_entry(struct cache_entry *ce, char *path, struct checkout *stat
 						 "symlink %s (%s)", path, strerror(errno));
 		}
 		break;
+	case S_IFDIRLNK:
+		if (to_tempfile)
+			return error("git-checkout-index: cannot create temporary subproject %s", path);
+		if (mkdir(path, 0777) < 0)
+			return error("git-checkout-index: cannot create subproject directory %s", path);
+		break;
 	default:
-		free(new);
 		return error("git-checkout-index: unknown file mode for %s", path);
 	}
 
@@ -179,6 +195,9 @@ int checkout_entry(struct cache_entry *ce, struct checkout *state, char *topath)
 		 */
 		unlink(path);
 		if (S_ISDIR(st.st_mode)) {
+			/* If it is a gitlink, leave it alone! */
+			if (S_ISDIRLNK(ntohl(ce->ce_mode)))
+				return 0;
 			if (!state->force)
 				return error("%s is a directory", path);
 			remove_subtree(path);