format-patch: refactor output selection

The --stdout and --output-directory options are mutually exclusive, but
it's hard to tell from reading the code. We have three separate
conditionals that check for use_stdout, and it's only after we've set up
the output_directory fully that we check whether the user also specified
--stdout.

Instead, let's check the exclusion explicitly first, then have a single
conditional that handles stdout versus an output directory. This is
slightly easier to follow now, and also will keep things sane when we
add another output mode in a future patch.

We'll add a few tests as well, covering the mutual exclusion and the
fact that we are not confused by a configured output directory.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

builtin/log.c

@@ -1942,20 +1942,20 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	if (rev.show_notes)
 		load_display_notes(&rev.notes_opt);
 
-	if (!output_directory && !use_stdout)
-		output_directory = config_output_directory;
+	if (use_stdout + !!output_directory > 1)
+		die(_("--stdout and --output-directory are mutually exclusive"));
 
-	if (!use_stdout)
-		output_directory = set_outdir(prefix, output_directory);
-	else
+	if (use_stdout) {
 		setup_pager();
-
-	if (output_directory) {
+	} else {
 		int saved;
+
+		if (!output_directory)
+			output_directory = config_output_directory;
+		output_directory = set_outdir(prefix, output_directory);
+
 		if (rev.diffopt.use_color != GIT_COLOR_ALWAYS)
 			rev.diffopt.use_color = GIT_COLOR_NEVER;
-		if (use_stdout)
-			die(_("standard output, or directory, which one?"));
 		/*
 		 * We consider <outdir> as 'outside of gitdir', therefore avoid
 		 * applying adjust_shared_perm in s-c-l-d.

t/t4014-format-patch.sh

@@ -1919,6 +1919,19 @@ test_expect_success 'format-patch -o overrides format.outputDirectory' '
 	test_path_is_dir patchset
 '
 
+test_expect_success 'format-patch forbids multiple outputs' '
+	rm -fr outdir &&
+	test_must_fail \
+		git format-patch --stdout --output-directory=outdir
+'
+
+test_expect_success 'configured outdir does not conflict with output options' '
+	rm -fr outdir &&
+	test_config format.outputDirectory outdir &&
+	git format-patch --stdout &&
+	test_path_is_missing outdir
+'
+
 test_expect_success 'format-patch --base' '
 	git checkout patchid &&