git diff -D: omit the preimage of deletes

diff --git a/diff.c b/diff.c
index 5422c438826254f36d1e00af0e8b882690661276..05f443c14ab2f083c642e88c0211da4a9aae7f99 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -572,11 +572,14 @@ static void emit_rewrite_diff(const char *name_a,
                line_prefix, metainfo, a_name.buf, name_a_tab, reset,
                line_prefix, metainfo, b_name.buf, name_b_tab, reset,
                line_prefix, fraginfo);
-       print_line_count(o->file, lc_a);
+       if (!o->irreversible_delete)
+               print_line_count(o->file, lc_a);
+       else
+               fprintf(o->file, "?,?");
        fprintf(o->file, " +");
        print_line_count(o->file, lc_b);
        fprintf(o->file, " @@%s\n", reset);
-       if (lc_a)
+       if (lc_a && !o->irreversible_delete)
                emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
        if (lc_b)
                emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
@@ -1943,7 +1946,11 @@ static void builtin_diff(const char *name_a,
                }
        }
 
-       if (!DIFF_OPT_TST(o, TEXT) &&
+       if (o->irreversible_delete && lbl[1][0] == '/') {
+               fprintf(o->file, "%s", header.buf);
+               strbuf_reset(&header);
+               goto free_ab_and_return;
+       } else if (!DIFF_OPT_TST(o, TEXT) &&
            ( (!textconv_one && diff_filespec_is_binary(one)) ||
              (!textconv_two && diff_filespec_is_binary(two)) )) {
                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
@@ -1963,8 +1970,7 @@ static void builtin_diff(const char *name_a,
                        fprintf(o->file, "%sBinary files %s and %s differ\n",
                                line_prefix, lbl[0], lbl[1]);
                o->found_changes = 1;
-       }
-       else {
+       } else {
                /* Crazy xdl interfaces.. */
                const char *diffopts = getenv("GIT_DIFF_OPTS");
                xpparam_t xpp;
@@ -3160,6 +3166,9 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
                        return error("invalid argument to -M: %s", arg+2);
                options->detect_rename = DIFF_DETECT_RENAME;
        }
+       else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
+               options->irreversible_delete = 1;
+       }
        else if (!prefixcmp(arg, "-C") || !prefixcmp(arg, "--find-copies=") ||
                 !strcmp(arg, "--find-copies")) {
                if (options->detect_rename == DIFF_DETECT_COPY)