Merge branch 'vd/mv-refresh-stat'

"git mv" failed to refresh the cached stat information for the
entry it moved.

* vd/mv-refresh-stat:
  mv: refresh stat info for moved entry

read-cache.c

@@ -134,7 +134,7 @@ static void replace_index_entry(struct index_state *istate, int nr, struct cache
 
 void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
 {
-	struct cache_entry *old_entry = istate->cache[nr], *new_entry;
+	struct cache_entry *old_entry = istate->cache[nr], *new_entry, *refreshed;
 	int namelen = strlen(new_name);
 
 	new_entry = make_empty_cache_entry(istate, namelen);
@@ -147,7 +147,20 @@ void rename_index_entry_at(struct index_state *istate, int nr, const char *new_n
 	cache_tree_invalidate_path(istate, old_entry->name);
 	untracked_cache_remove_from_index(istate, old_entry->name);
 	remove_index_entry_at(istate, nr);
-	add_index_entry(istate, new_entry, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
+
+	/*
+	 * Refresh the new index entry. Using 'refresh_cache_entry' ensures
+	 * we only update stat info if the entry is otherwise up-to-date (i.e.,
+	 * the contents/mode haven't changed). This ensures that we reflect the
+	 * 'ctime' of the rename in the index without (incorrectly) updating
+	 * the cached stat info to reflect unstaged changes on disk.
+	 */
+	refreshed = refresh_cache_entry(istate, new_entry, CE_MATCH_REFRESH);
+	if (refreshed && refreshed != new_entry) {
+		add_index_entry(istate, refreshed, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
+		discard_cache_entry(new_entry);
+	} else
+		add_index_entry(istate, new_entry, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
 }
 
 void fill_stat_data(struct stat_data *sd, struct stat *st)

t/t7001-mv.sh

@@ -4,6 +4,25 @@ test_description='git mv in subdirs'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-diff-data.sh
 
+test_expect_success 'mv -f refreshes updated index entry' '
+	echo test >bar &&
+	git add bar &&
+	git commit -m test &&
+
+	echo foo >foo &&
+	git add foo &&
+
+	# Wait one second to ensure ctime of rename will differ from original
+	# file creation ctime.
+	sleep 1 &&
+	git mv -f foo bar &&
+	git reset --merge HEAD &&
+
+	# Verify the index has been reset
+	git diff-files >out &&
+	test_must_be_empty out
+'
+
 test_expect_success 'prepare reference tree' '
 	mkdir path0 path1 &&
 	COPYING_test_data >path0/COPYING &&