[PATCH 2/2] ignorecase: Fix git mv on insensitive filesystems

[dturner@twopensource.com]

From: David Turner <dturner@twitter.com>

Make it possible to change the case of a filename on a
case-insensitive filesystem using git mv.  Change git mv to allow
moves where the destination file exists if either the destination file
has the same inode as the source file (for Mac) or the same name
ignoring case (for Win).

Signed-off-by: David Turner <dturner@twitter.com>
---
 builtin/mv.c                | 18 ++++++++++--------
 t/t6039-merge-ignorecase.sh |  2 +-
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/builtin/mv.c b/builtin/mv.c
index 45e57f3..8cead13 100644
--- a/builtin/mv.c
+++ b/builtin/mv.c
@@ -74,7 +74,7 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 	};
 	const char **source, **destination, **dest_path, **submodule_gitfile;
 	enum update_mode { BOTH = 0, WORKING_DIRECTORY, INDEX } *modes;
-	struct stat st;
+	struct stat src_st,dst_st;
 	struct string_list src_for_dst = STRING_LIST_INIT_NODUP;
 
 	gitmodules_config();
@@ -102,8 +102,8 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 	if (dest_path[0][0] == '\0')
 		/* special case: "." was normalized to "" */
 		destination = internal_copy_pathspec(dest_path[0], argv, argc, DUP_BASENAME);
-	else if (!lstat(dest_path[0], &st) &&
-			S_ISDIR(st.st_mode)) {
+	else if (!lstat(dest_path[0], &dst_st) &&
+			S_ISDIR(dst_st.st_mode)) {
 		dest_path[0] = add_slash(dest_path[0]);
 		destination = internal_copy_pathspec(dest_path[0], argv, argc, DUP_BASENAME);
 	} else {
@@ -122,13 +122,13 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 			printf(_("Checking rename of '%s' to '%s'\n"), src, dst);
 
 		length = strlen(src);
-		if (lstat(src, &st) < 0)
+		if (lstat(src, &src_st) < 0)
 			bad = _("bad source");
 		else if (!strncmp(src, dst, length) &&
 				(dst[length] == 0 || dst[length] == '/')) {
 			bad = _("can not move directory into itself");
-		} else if ((src_is_dir = S_ISDIR(st.st_mode))
-				&& lstat(dst, &st) == 0)
+		} else if ((src_is_dir = S_ISDIR(src_st.st_mode))
+				&& lstat(dst, &dst_st) == 0)
 			bad = _("cannot move directory over file");
 		else if (src_is_dir) {
 			int first = cache_name_pos(src, length);
@@ -202,14 +202,16 @@ int cmd_mv(int argc, const char **argv, const char *prefix)
 			}
 		} else if (cache_name_pos(src, length) < 0)
 			bad = _("not under version control");
-		else if (lstat(dst, &st) == 0) {
+		else if (lstat(dst, &dst_st) == 0 &&
+			 (src_st.st_ino != dst_st.st_ino ||
+			  (src_st.st_ino == 0 && strcasecmp(src, dst)))) {
 			bad = _("destination exists");
 			if (force) {
 				/*
 				 * only files can overwrite each other:
 				 * check both source and destination
 				 */
-				if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
+				if (S_ISREG(dst_st.st_mode) || S_ISLNK(dst_st.st_mode)) {
 					if (verbose)
 						warning(_("overwriting '%s'"), dst);
 					bad = NULL;
diff --git a/t/t6039-merge-ignorecase.sh b/t/t6039-merge-ignorecase.sh
index ad06752..28cfb49 100755
--- a/t/t6039-merge-ignorecase.sh
+++ b/t/t6039-merge-ignorecase.sh
@@ -35,7 +35,7 @@ test_expect_success 'merge with case-changing rename on both sides' '
 	git reset --hard baseline &&
 	git branch -D with-camel &&
 	git checkout -b with-camel &&
-	git mv --force TestCase testcase &&
+	git mv TestCase testcase &&
 	git commit -m "recase on branch" &&
 	> foo &&
 	git add foo &&
-- 
2.0.0.rc0.33.g27630aa