Merge pull request #3922 from pks-t/pks/diff-only-load-binaries-when-requested

patch_generate: only calculate binary diffs if requested

src/patch_generate.c

@@ -349,6 +349,9 @@ static int diff_binary(git_patch_generated_output *output, git_patch_generated *
 		new_len = patch->nfile.map.len;
 	int error;
 
+	/* Only load contents if the user actually wants to diff
+	 * binary files. */
+	if (patch->base.diff_opts.flags & GIT_DIFF_SHOW_BINARY) {
 		/* Create the old->new delta (as the "new" side of the patch),
 		 * and the new->old delta (as the "old" side)
 		 */
@@ -363,6 +366,7 @@ static int diff_binary(git_patch_generated_output *output, git_patch_generated *
 				&binary.new_file.inflatedlen,
 				old_data, old_len, new_data, new_len)) < 0)
 			return error;
+	}
 
 	error = giterr_set_after_callback_function(
 		output->binary_cb(patch->base.delta, &binary, output->payload),