teach diffcore-rename to optionally ignore empty content

diff --git a/diff.c b/diff.c
index f47bffa2a3641cbf69b2e6d3f0f6c93b05f2c716..0b70aadc4f973d66460b04cb300c632b61317961 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -2255,7 +2255,7 @@ static void builtin_diff(const char *name_a,
                struct emit_callback ecbdata;
                const struct userdiff_funcname *pe;
 
-               if (!DIFF_XDL_TST(o, WHITESPACE_FLAGS) || must_show_header) {
+               if (must_show_header) {
                        fprintf(o->file, "%s", header.buf);
                        strbuf_reset(&header);
                }
@@ -3136,6 +3136,7 @@ void diff_setup(struct diff_options *options)
        options->rename_limit = -1;
        options->dirstat_permille = diff_dirstat_permille_default;
        options->context = 3;
+       DIFF_OPT_SET(options, RENAME_EMPTY);
 
        options->change = diff_change;
        options->add_remove = diff_addremove;
@@ -3506,6 +3507,10 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
        }
        else if (!strcmp(arg, "--no-renames"))
                options->detect_rename = 0;
+       else if (!strcmp(arg, "--rename-empty"))
+               DIFF_OPT_SET(options, RENAME_EMPTY);
+       else if (!strcmp(arg, "--no-rename-empty"))
+               DIFF_OPT_CLR(options, RENAME_EMPTY);
        else if (!strcmp(arg, "--relative"))
                DIFF_OPT_SET(options, RELATIVE_NAME);
        else if (!prefixcmp(arg, "--relative=")) {