1 files changed, 28 insertions, 16 deletions

diff --git a/tree-diff.c b/tree-diff.c
index fe9f52c479..12c9a88884 100644
--- a/tree-diff.c
+++ b/tree-diff.c
@@ -85,6 +85,8 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const
 /*
  * Is a tree entry interesting given the pathspec we have?
  *
+ * Pre-condition: baselen == 0 || base[baselen-1] == '/'
+ *
  * Return:
  *  - 2 for "yes, and all subsequent entries will be"
  *  - 1 for yes
@@ -101,7 +103,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 	int never_interesting = -1;
 
 	if (!opt->nr_paths)
-		return 1;
+		return 2;
 
 	sha1 = tree_entry_extract(desc, &path, &mode);
 
@@ -257,19 +259,12 @@ static void show_entry(struct diff_options *opt, const char *prefix, struct tree
 	}
 }
 
-static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt)
+static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt, int *all_interesting)
 {
-	int all_interesting = 0;
 	while (t->size) {
-		int show;
-
-		if (all_interesting)
-			show = 1;
-		else {
-			show = tree_entry_interesting(t, base, baselen, opt);
-			if (show == 2)
-				all_interesting = 1;
-		}
+		int show = tree_entry_interesting(t, base, baselen, opt);
+		if (show == 2)
+			*all_interesting = 1;
 		if (!show) {
 			update_tree_entry(t);
 			continue;
@@ -284,14 +279,20 @@ static void skip_uninteresting(struct tree_desc *t, const char *base, int basele
 int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
 {
 	int baselen = strlen(base);
+	int all_t1_interesting = 0;
+	int all_t2_interesting = 0;
 
 	for (;;) {
 		if (DIFF_OPT_TST(opt, QUICK) &&
 		    DIFF_OPT_TST(opt, HAS_CHANGES))
 			break;
 		if (opt->nr_paths) {
-			skip_uninteresting(t1, base, baselen, opt);
-			skip_uninteresting(t2, base, baselen, opt);
+			if (!all_t1_interesting)
+				skip_uninteresting(t1, base, baselen, opt,
+						   &all_t1_interesting);
+			if (!all_t2_interesting)
+				skip_uninteresting(t2, base, baselen, opt,
+						   &all_t2_interesting);
 		}
 		if (!t1->size) {
 			if (!t2->size)
@@ -346,7 +347,7 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
 
 	diff_setup(&diff_opts);
 	DIFF_OPT_SET(&diff_opts, RECURSIVE);
-	diff_opts.detect_rename = DIFF_DETECT_RENAME;
+	DIFF_OPT_SET(&diff_opts, FIND_COPIES_HARDER);
 	diff_opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 	diff_opts.single_follow = opt->paths[0];
 	diff_opts.break_opt = opt->break_opt;
@@ -359,6 +360,7 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
 	diff_tree_release_paths(&diff_opts);
 
 	/* Go through the new set of filepairing, and see if we find a more interesting one */
+	opt->found_follow = 0;
 	for (i = 0; i < q->nr; i++) {
 		struct diff_filepair *p = q->queue[i];
 
@@ -376,6 +378,16 @@ static void try_to_follow_renames(struct tree_desc *t1, struct tree_desc *t2, co
 			diff_tree_release_paths(opt);
 			opt->paths[0] = xstrdup(p->one->path);
 			diff_tree_setup_paths(opt->paths, opt);
+
+			/*
+			 * The caller expects us to return a set of vanilla
+			 * filepairs to let a later call to diffcore_std()
+			 * it makes to sort the renames out (among other
+			 * things), but we already have found renames
+			 * ourselves; signal diffcore_std() not to muck with
+			 * rename information.
+			 */
+			opt->found_follow = 1;
 			break;
 		}
 	}
@@ -412,7 +424,7 @@ int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const cha
 	init_tree_desc(&t1, tree1, size1);
 	init_tree_desc(&t2, tree2, size2);
 	retval = diff_tree(&t1, &t2, base, opt);
-	if (DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
+	if (!*base && DIFF_OPT_TST(opt, FOLLOW_RENAMES) && diff_might_be_rename()) {
 		init_tree_desc(&t1, tree1, size1);
 		init_tree_desc(&t2, tree2, size2);
 		try_to_follow_renames(&t1, &t2, base, opt);