diff: shortcut for diff'ing two binary SHA-1 objects

diff --git a/diff.c b/diff.c
index d381a6f446f36c441396077075d33d0daefd4b71..b85bcfbf52e52dbd5521dde1078de9593d772f67 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -2324,6 +2324,19 @@ static void builtin_diff(const char *name_a,
        } else if (!DIFF_OPT_TST(o, TEXT) &&
            ( (!textconv_one && diff_filespec_is_binary(one)) ||
              (!textconv_two && diff_filespec_is_binary(two)) )) {
+               if (!one->data && !two->data &&
+                   S_ISREG(one->mode) && S_ISREG(two->mode) &&
+                   !DIFF_OPT_TST(o, BINARY)) {
+                       if (!hashcmp(one->sha1, two->sha1)) {
+                               if (must_show_header)
+                                       fprintf(o->file, "%s", header.buf);
+                               goto free_ab_and_return;
+                       }
+                       fprintf(o->file, "%s", header.buf);
+                       fprintf(o->file, "%sBinary files %s and %s differ\n",
+                               line_prefix, lbl[0], lbl[1]);
+                       goto free_ab_and_return;
+               }
                if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
                        die("unable to read files to diff");
                /* Quite common confusing case */