[PATCH v2 2/6] git.c: add a NEED_UNIX_SOCKETS option for built-ins

@@ -63,6 +63,12 @@
  *	more informed decision, e.g., by ignoring `pager.<cmd>` for
  *	certain subcommands.
  *
+ * `NEED_UNIX_SOCKETS`:
+ *
+ *	This built-in will not work if NO_UNIX_SOCKETS is defined. It
+ *	will be recognized for emitting error messages, but won't be
+ *	listed in --list-cmds=builtins.
+ *
  * . Add `builtin/foo.o` to `BUILTIN_OBJS` in `Makefile`.
  *
  * Additionally, if `foo` is a new command, there are 4 more things to do:

@@ -304,16 +304,7 @@ int cmd_credential_cache_daemon(int argc, const char **argv, const char *prefix)
 
 int cmd_credential_cache_daemon(int argc, const char **argv, const char *prefix)
 {
-	const char * const usage[] = {
-		"git credential-cache--daemon [options] <action>",
-		"",
-		"credential-cache--daemon is disabled in this build of Git",
-		NULL
-	};
-	struct option options[] = { OPT_END() };
-
-	argc = parse_options(argc, argv, prefix, options, usage, 0);
-	die(_("credential-cache--daemon unavailable; no unix socket support"));
+	BUG("should not be called under NO_UNIX_SOCKETS");
 }
 
 #endif /* NO_UNIX_SOCKET */

@@ -142,16 +142,7 @@ int cmd_credential_cache(int argc, const char **argv, const char *prefix)
 
 int cmd_credential_cache(int argc, const char **argv, const char *prefix)
 {
-	const char * const usage[] = {
-		"git credential-cache [options] <action>",
-		"",
-		"credential-cache is disabled in this build of Git",
-		NULL
-	};
-	struct option options[] = { OPT_END() };
-
-	argc = parse_options(argc, argv, prefix, options, usage, 0);
-	die(_("credential-cache unavailable; no unix socket support"));
+	BUG("should not be called under NO_UNIX_SOCKETS");
 }
 
 #endif /* NO_UNIX_SOCKETS */

@@ -17,6 +17,7 @@
 #define SUPPORT_SUPER_PREFIX	(1<<4)
 #define DELAY_PAGER_CONFIG	(1<<5)
 #define NO_PARSEOPT		(1<<6) /* parse-options is not used */
+#define NEED_UNIX_SOCKETS	(1<<7) /* Works unless -DNO_UNIX_SOCKETS */
 
 struct cmd_struct {
 	const char *cmd;

@@ -66,6 +67,10 @@ static int list_cmds(const char *spec)
 	struct string_list list = STRING_LIST_INIT_DUP;
 	int i;
 	int nongit;
+	unsigned int exclude_option = 0;
+#ifdef NO_UNIX_SOCKETS
+	exclude_option |= NEED_UNIX_SOCKETS;
+#endif
 
 	/*
 	* Set up the repository so we can pick up any repo-level config (like

@@ -78,7 +83,7 @@ static int list_cmds(const char *spec)
 		int len = sep - spec;
 
 		if (match_token(spec, len, "builtins"))
-			list_builtins(&list, 0);
+			list_builtins(&list, exclude_option);
 		else if (match_token(spec, len, "main"))
 			list_all_main_cmds(&list);
 		else if (match_token(spec, len, "others"))

@@ -423,6 +428,10 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 	const char *prefix;
 
 	prefix = NULL;
+#ifdef NO_UNIX_SOCKETS
+	if (p->option & NEED_UNIX_SOCKETS)
+		die(_("%s is unavailable; there is no UNIX socket support in this build of Git"), p->cmd);
+#endif
 	help = argc == 2 && !strcmp(argv[1], "-h");
 	if (!help) {
 		if (p->option & RUN_SETUP)

@@ -513,8 +522,8 @@ static struct cmd_struct commands[] = {
 	{ "config", cmd_config, RUN_SETUP_GENTLY | DELAY_PAGER_CONFIG },
 	{ "count-objects", cmd_count_objects, RUN_SETUP },
 	{ "credential", cmd_credential, RUN_SETUP_GENTLY | NO_PARSEOPT },
-	{ "credential-cache", cmd_credential_cache },
-	{ "credential-cache--daemon", cmd_credential_cache_daemon },
+	{ "credential-cache", cmd_credential_cache, NEED_UNIX_SOCKETS },
+	{ "credential-cache--daemon", cmd_credential_cache_daemon, NEED_UNIX_SOCKETS },
 	{ "credential-store", cmd_credential_store },
 	{ "describe", cmd_describe, RUN_SETUP },
 	{ "diff", cmd_diff, NO_PARSEOPT },

@@ -85,4 +85,14 @@ do
 	'
 done <builtins
 
+test_expect_success UNIX_SOCKETS 'builtin list includes NEED_UNIX_SOCKETS under UNIX_SOCKETS' '
+	grep ^credential-cache$ builtins &&
+	grep ^credential-cache--daemon$ builtins
+'
+
+test_expect_success !UNIX_SOCKETS 'builtin list excludes NEED_UNIX_SOCKETS under !UNIX_SOCKETS' '
+	! grep ^credential-cache$ builtins &&
+	! grep ^credential-cache--daemon$ builtins
+'
+
 test_done