run-command API users: use strvec_push(), not argv construction

Change a pattern of hardcoding an "argv" array size, populating it and
assigning to the "argv" member of "struct child_process" to instead
use "strvec_push()" to add data to the "args" member.

As noted in the preceding commit this moves us further towards being
able to remove the "argv" member in a subsequent commit

These callers could have used strvec_pushl(), but moving to
strvec_push() makes the diff easier to read, and keeps the arguments
aligned as before.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

archive-tar.c

@@ -430,7 +430,6 @@ static int write_tar_filter_archive(const struct archiver *ar,
 {
 	struct strbuf cmd = STRBUF_INIT;
 	struct child_process filter = CHILD_PROCESS_INIT;
-	const char *argv[2];
 	int r;
 
 	if (!ar->data)
@@ -440,14 +439,12 @@ static int write_tar_filter_archive(const struct archiver *ar,
 	if (args->compression_level >= 0)
 		strbuf_addf(&cmd, " -%d", args->compression_level);
 
-	argv[0] = cmd.buf;
-	argv[1] = NULL;
-	filter.argv = argv;
+	strvec_push(&filter.args, cmd.buf);
 	filter.use_shell = 1;
 	filter.in = -1;
 
 	if (start_command(&filter) < 0)
-		die_errno(_("unable to start '%s' filter"), argv[0]);
+		die_errno(_("unable to start '%s' filter"), cmd.buf);
 	close(1);
 	if (dup2(filter.in, 1) < 0)
 		die_errno(_("unable to redirect descriptor"));
@@ -457,7 +454,7 @@ static int write_tar_filter_archive(const struct archiver *ar,
 
 	close(1);
 	if (finish_command(&filter) != 0)
-		die(_("'%s' filter reported error"), argv[0]);
+		die(_("'%s' filter reported error"), cmd.buf);
 
 	strbuf_release(&cmd);
 	return r;

builtin/receive-pack.c

@@ -812,16 +812,13 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed,
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
 	struct async muxer;
-	const char *argv[2];
 	int code;
+	const char *hook_path = find_hook(hook_name);
 
-	argv[0] = find_hook(hook_name);
-	if (!argv[0])
+	if (!hook_path)
 		return 0;
 
-	argv[1] = NULL;
-
-	proc.argv = argv;
+	strvec_push(&proc.args, hook_path);
 	proc.in = -1;
 	proc.stdout_to_stderr = 1;
 	proc.trace2_hook_name = hook_name;
@@ -943,23 +940,21 @@ static int run_receive_hook(struct command *commands,
 
 static int run_update_hook(struct command *cmd)
 {
-	const char *argv[5];
 	struct child_process proc = CHILD_PROCESS_INIT;
 	int code;
+	const char *hook_path = find_hook("update");
 
-	argv[0] = find_hook("update");
-	if (!argv[0])
+	if (!hook_path)
 		return 0;
 
-	argv[1] = cmd->ref_name;
-	argv[2] = oid_to_hex(&cmd->old_oid);
-	argv[3] = oid_to_hex(&cmd->new_oid);
-	argv[4] = NULL;
+	strvec_push(&proc.args, hook_path);
+	strvec_push(&proc.args, cmd->ref_name);
+	strvec_push(&proc.args, oid_to_hex(&cmd->old_oid));
+	strvec_push(&proc.args, oid_to_hex(&cmd->new_oid));
 
 	proc.no_stdin = 1;
 	proc.stdout_to_stderr = 1;
 	proc.err = use_sideband ? -1 : 0;
-	proc.argv = argv;
 	proc.trace2_hook_name = "update";
 
 	code = start_command(&proc);
@@ -1117,22 +1112,20 @@ static int run_proc_receive_hook(struct command *commands,
 	struct child_process proc = CHILD_PROCESS_INIT;
 	struct async muxer;
 	struct command *cmd;
-	const char *argv[2];
 	struct packet_reader reader;
 	struct strbuf cap = STRBUF_INIT;
 	struct strbuf errmsg = STRBUF_INIT;
 	int hook_use_push_options = 0;
 	int version = 0;
 	int code;
+	const char *hook_path = find_hook("proc-receive");
 
-	argv[0] = find_hook("proc-receive");
-	if (!argv[0]) {
+	if (!hook_path) {
 		rp_error("cannot find hook 'proc-receive'");
 		return -1;
 	}
-	argv[1] = NULL;
 
-	proc.argv = argv;
+	strvec_push(&proc.args, hook_path);
 	proc.in = -1;
 	proc.out = -1;
 	proc.trace2_hook_name = "proc-receive";

daemon.c

@@ -326,22 +326,18 @@ static int run_access_hook(struct daemon_service *service, const char *dir,
 {
 	struct child_process child = CHILD_PROCESS_INIT;
 	struct strbuf buf = STRBUF_INIT;
-	const char *argv[8];
-	const char **arg = argv;
 	char *eol;
 	int seen_errors = 0;
 
-	*arg++ = access_hook;
-	*arg++ = service->name;
-	*arg++ = path;
-	*arg++ = hi->hostname.buf;
-	*arg++ = get_canon_hostname(hi);
-	*arg++ = get_ip_address(hi);
-	*arg++ = hi->tcp_port.buf;
-	*arg = NULL;
+	strvec_push(&child.args, access_hook);
+	strvec_push(&child.args, service->name);
+	strvec_push(&child.args, path);
+	strvec_push(&child.args, hi->hostname.buf);
+	strvec_push(&child.args, get_canon_hostname(hi));
+	strvec_push(&child.args, get_ip_address(hi));
+	strvec_push(&child.args, hi->tcp_port.buf);
 
 	child.use_shell = 1;
-	child.argv = argv;
 	child.no_stdin = 1;
 	child.no_stderr = 1;
 	child.out = -1;

diff.c

@@ -6921,19 +6921,15 @@ static char *run_textconv(struct repository *r,
 			  size_t *outsize)
 {
 	struct diff_tempfile *temp;
-	const char *argv[3];
-	const char **arg = argv;
 	struct child_process child = CHILD_PROCESS_INIT;
 	struct strbuf buf = STRBUF_INIT;
 	int err = 0;
 
 	temp = prepare_temp_file(r, spec->path, spec);
-	*arg++ = pgm;
-	*arg++ = temp->name;
-	*arg = NULL;
+	strvec_push(&child.args, pgm);
+	strvec_push(&child.args, temp->name);
 
 	child.use_shell = 1;
-	child.argv = argv;
 	child.out = -1;
 	if (start_command(&child)) {
 		remove_tempfile();

prompt.c

@@ -8,15 +8,12 @@
 static char *do_askpass(const char *cmd, const char *prompt)
 {
 	struct child_process pass = CHILD_PROCESS_INIT;
-	const char *args[3];
 	static struct strbuf buffer = STRBUF_INIT;
 	int err = 0;
 
-	args[0] = cmd;
-	args[1]	= prompt;
-	args[2] = NULL;
+	strvec_push(&pass.args, cmd);
+	strvec_push(&pass.args, prompt);
 
-	pass.argv = args;
 	pass.out = -1;
 
 	if (start_command(&pass))

transport.c

@@ -1204,16 +1204,15 @@ static int run_pre_push_hook(struct transport *transport,
 	struct ref *r;
 	struct child_process proc = CHILD_PROCESS_INIT;
 	struct strbuf buf;
-	const char *argv[4];
+	const char *hook_path = find_hook("pre-push");
 
-	if (!(argv[0] = find_hook("pre-push")))
+	if (!hook_path)
 		return 0;
 
-	argv[1] = transport->remote->name;
-	argv[2] = transport->url;
-	argv[3] = NULL;
+	strvec_push(&proc.args, hook_path);
+	strvec_push(&proc.args, transport->remote->name);
+	strvec_push(&proc.args, transport->url);
 
-	proc.argv = argv;
 	proc.in = -1;
 	proc.trace2_hook_name = "pre-push";