submodule: use prepare_submodule_repo_env consistently

Before 14111fc (git: submodule honor -c credential.* from
command line, 2016-02-29), it was sufficient for code which
spawned a process in a submodule to just set the child
process's "env" field to "local_repo_env" to clear the
environment of any repo-specific variables.

That commit introduced a more complicated procedure, in
which we clear most variables but allow through sanitized
config. For C code, we used that procedure only for cloning,
but not for any of the programs spawned by submodule.c. As a
result, things like "git fetch --recurse-submodules" behave
differently than "git clone --recursive"; the former will
not pass through the sanitized config.

We can fix this by using prepare_submodule_repo_env()
everywhere in submodule.c.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

submodule.c

@@ -367,7 +367,7 @@ static int submodule_needs_pushing(const char *path, const unsigned char sha1[20
 
 		argv[1] = sha1_to_hex(sha1);
 		cp.argv = argv;
-		cp.env = local_repo_env;
+		prepare_submodule_repo_env(&cp.env_array);
 		cp.git_cmd = 1;
 		cp.no_stdin = 1;
 		cp.out = -1;
@@ -454,7 +454,7 @@ static int push_submodule(const char *path)
 		const char *argv[] = {"push", NULL};
 
 		cp.argv = argv;
-		cp.env = local_repo_env;
+		prepare_submodule_repo_env(&cp.env_array);
 		cp.git_cmd = 1;
 		cp.no_stdin = 1;
 		cp.dir = path;
@@ -500,7 +500,7 @@ static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
 
 		argv[3] = sha1_to_hex(sha1);
 		cp.argv = argv;
-		cp.env = local_repo_env;
+		prepare_submodule_repo_env(&cp.env_array);
 		cp.git_cmd = 1;
 		cp.no_stdin = 1;
 		cp.dir = path;
@@ -683,7 +683,7 @@ static int get_next_submodule(struct child_process *cp,
 		if (is_directory(git_dir)) {
 			child_process_init(cp);
 			cp->dir = strbuf_detach(&submodule_path, NULL);
-			cp->env = local_repo_env;
+			prepare_submodule_repo_env(&cp->env_array);
 			cp->git_cmd = 1;
 			if (!spf->quiet)
 				strbuf_addf(err, "Fetching submodule %s%s\n",
@@ -796,7 +796,7 @@ unsigned is_submodule_modified(const char *path, int ignore_untracked)
 		argv[2] = "-uno";
 
 	cp.argv = argv;
-	cp.env = local_repo_env;
+	prepare_submodule_repo_env(&cp.env_array);
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
 	cp.out = -1;
@@ -857,7 +857,7 @@ int submodule_uses_gitfile(const char *path)
 
 	/* Now test that all nested submodules use a gitfile too */
 	cp.argv = argv;
-	cp.env = local_repo_env;
+	prepare_submodule_repo_env(&cp.env_array);
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
 	cp.no_stderr = 1;
@@ -890,7 +890,7 @@ int ok_to_remove_submodule(const char *path)
 		return 0;
 
 	cp.argv = argv;
-	cp.env = local_repo_env;
+	prepare_submodule_repo_env(&cp.env_array);
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
 	cp.out = -1;

t/t5550-http-fetch-dumb.sh

@@ -112,6 +112,17 @@ test_expect_success 'cmdline credential config passes to submodule via clone' '
 	expect_askpass pass user@host
 '
 
+test_expect_success 'cmdline credential config passes submodule via fetch' '
+	set_askpass wrong pass@host &&
+	test_must_fail git -C super-clone fetch --recurse-submodules &&
+
+	set_askpass wrong pass@host &&
+	git -C super-clone \
+	    -c "credential.$HTTPD_URL.username=user@host" \
+	    fetch --recurse-submodules &&
+	expect_askpass pass user@host
+'
+
 test_expect_success 'cmdline credential config passes submodule update' '
 	# advance the submodule HEAD so that a fetch is required
 	git commit --allow-empty -m foo &&