t7450: test submodule urls

Add tests to 't7450-bad-git-dotfiles.sh' to check the validity of different
submodule URLs. To verify this directly (without setting up test
repositories & submodules), add a 'check-url' subcommand to 'test-tool
submodule' that calls 'check_submodule_url' in the same way that
'check-name' calls 'check_submodule_name'.

Add two tests to separately address cases where the URL check correctly
filters out invalid URLs and cases where the check misses invalid URLs. Mark
the latter ("url check misses invalid cases") with 'test_expect_failure' to
indicate that this not the undesired behavior.

Signed-off-by: Victoria Dye <vdye@github.com>

t/helper/test-submodule.c

@@ -15,6 +15,13 @@ static const char *submodule_check_name_usage[] = {
 	NULL
 };
 
+#define TEST_TOOL_CHECK_URL_USAGE \
+	"test-tool submodule check-url"
+static const char *submodule_check_url_usage[] = {
+	TEST_TOOL_CHECK_URL_USAGE,
+	NULL
+};
+
 #define TEST_TOOL_IS_ACTIVE_USAGE \
 	"test-tool submodule is-active <name>"
 static const char *submodule_is_active_usage[] = {
@@ -31,17 +38,23 @@ static const char *submodule_resolve_relative_url_usage[] = {
 
 static const char *submodule_usage[] = {
 	TEST_TOOL_CHECK_NAME_USAGE,
+	TEST_TOOL_CHECK_URL_USAGE,
 	TEST_TOOL_IS_ACTIVE_USAGE,
 	TEST_TOOL_RESOLVE_RELATIVE_URL_USAGE,
 	NULL
 };
 
-/* Filter stdin to print only valid names. */
-static int check_name(void)
+typedef int (*check_fn_t)(const char *);
+
+/*
+ * Apply 'check_fn' to each line of stdin, printing values that pass the check
+ * to stdout.
+ */
+static int check_submodule(check_fn_t check_fn)
 {
 	struct strbuf buf = STRBUF_INIT;
 	while (strbuf_getline(&buf, stdin) != EOF) {
-		if (!check_submodule_name(buf.buf))
+		if (!check_fn(buf.buf))
 			printf("%s\n", buf.buf);
 	}
 	strbuf_release(&buf);
@@ -58,7 +71,20 @@ static int cmd__submodule_check_name(int argc, const char **argv)
 	if (argc)
 		usage_with_options(submodule_check_name_usage, options);
 
-	return check_name();
+	return check_submodule(check_submodule_name);
+}
+
+static int cmd__submodule_check_url(int argc, const char **argv)
+{
+	struct option options[] = {
+		OPT_END()
+	};
+	argc = parse_options(argc, argv, "test-tools", options,
+			     submodule_check_url_usage, 0);
+	if (argc)
+		usage_with_options(submodule_check_url_usage, options);
+
+	return check_submodule(check_submodule_url);
 }
 
 static int cmd__submodule_is_active(int argc, const char **argv)
@@ -184,6 +210,7 @@ static int cmd__submodule_config_writeable(int argc, const char **argv UNUSED)
 
 static struct test_cmd cmds[] = {
 	{ "check-name", cmd__submodule_check_name },
+	{ "check-url", cmd__submodule_check_url },
 	{ "is-active", cmd__submodule_is_active },
 	{ "resolve-relative-url", cmd__submodule_resolve_relative_url},
 	{ "config-list", cmd__submodule_config_list },

t/t7450-bad-git-dotfiles.sh

@@ -45,6 +45,41 @@ test_expect_success 'check names' '
 	test_cmp expect actual
 '
 
+test_expect_success 'check urls' '
+	cat >expect <<-\EOF &&
+	./bar/baz/foo.git
+	https://example.com/foo.git
+	http://example.com:80/deeper/foo.git
+	EOF
+
+	test-tool submodule check-url >actual <<-\EOF &&
+	./bar/baz/foo.git
+	https://example.com/foo.git
+	http://example.com:80/deeper/foo.git
+	-a./foo
+	../../..//test/foo.git
+	../../../../../:localhost:8080/foo.git
+	..\../.\../:example.com/foo.git
+	./%0ahost=example.com/foo.git
+	https://one.example.com/evil?%0ahost=two.example.com
+	https:///example.com/foo.git
+	https::example.com/foo.git
+	http:::example.com/foo.git
+	EOF
+
+	test_cmp expect actual
+'
+
+# NEEDSWORK: the URL checked here is not valid (and will not work as a remote if
+# a user attempts to clone it), but the fsck check passes.
+test_expect_failure 'url check misses invalid cases' '
+	test-tool submodule check-url >actual <<-\EOF &&
+	http://example.com:test/foo.git
+	EOF
+
+	test_must_be_empty actual
+'
+
 test_expect_success 'create innocent subrepo' '
 	git init innocent &&
 	git -C innocent commit --allow-empty -m foo