Merge branch 'rs/diff-exit-code-fix' into maint-2.46

In a few corner cases "git diff --exit-code" failed to report
"changes" (e.g., renamed without any content change), which has
been corrected.

* rs/diff-exit-code-fix:
  diff: report dirty submodules as changes in builtin_diff()
  diff: report copies and renames as changes in run_diff_cmd()

Author: gitster

diff.c

@@ -3565,6 +3565,7 @@ static void builtin_diff(const char *name_a,
 		show_submodule_diff_summary(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
+		o->found_changes = 1;
 		return;
 	} else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
 		   (!one->mode || S_ISGITLINK(one->mode)) &&
@@ -3573,6 +3574,7 @@ static void builtin_diff(const char *name_a,
 		show_submodule_inline_diff(o, one->path ? one->path : two->path,
 				&one->oid, &two->oid,
 				two->dirty_submodule);
+		o->found_changes = 1;
 		return;
 	}
 
@@ -4587,6 +4589,9 @@ static void run_diff_cmd(const struct external_diff *pgm,
 		builtin_diff(name, other ? other : name,
 			     one, two, xfrm_msg, must_show_header,
 			     o, complete_rewrite);
+		if (p->status == DIFF_STATUS_COPIED ||
+		    p->status == DIFF_STATUS_RENAMED)
+			o->found_changes = 1;
 	} else {
 		fprintf(o->file, "* Unmerged path %s\n", name);
 		o->found_changes = 1;

t/t4017-diff-retval.sh

@@ -143,4 +143,41 @@ test_expect_success 'option errors are not confused by --exit-code' '
 	grep '^usage:' err
 '
 
+for option in --exit-code --quiet
+do
+	test_expect_success "git diff $option returns 1 for copied file" "
+		git reset --hard &&
+		cp a copy &&
+		git add copy &&
+		test_expect_code 1 git diff $option --cached --find-copies-harder
+	"
+
+	test_expect_success "git diff $option returns 1 for renamed file" "
+		git reset --hard &&
+		git mv a renamed &&
+		test_expect_code 1 git diff $option --cached
+	"
+done
+
+test_expect_success 'setup dirty subrepo' '
+	git reset --hard &&
+	test_create_repo subrepo &&
+	test_commit -C subrepo subrepo-file &&
+	test_tick &&
+	git add subrepo &&
+	git commit -m subrepo &&
+	test_commit -C subrepo another-subrepo-file
+'
+
+for option in --exit-code --quiet
+do
+	for submodule_format in diff log short
+	do
+		opts="$option --submodule=$submodule_format" &&
+		test_expect_success "git diff $opts returns 1 for dirty subrepo" "
+			test_expect_code 1 git diff $opts
+		"
+	done
+done
+
 test_done