remote: refactor insteadof application

Using the insteadof helper would leak memory when we didn't really want
the pushInsteadOf configuration.  Refactor the choice into the function
that allocates memory (or now, not) and use a more idiomatic `int`
return code.

src/remote.c

@@ -30,7 +30,7 @@
 
 static int dwim_refspecs(git_vector *out, git_vector *refspecs, git_vector *refs);
 static int lookup_remote_prune_config(git_remote *remote, git_config *config, const char *name);
-char *apply_insteadof(bool *matched, git_config *config, const char *url, int direction);
+static int apply_insteadof(char **out, git_config *config, const char *url, int direction, bool use_default_if_empty);
 
 static int add_refspec_to(git_vector *vector, const char *string, bool is_fetch)
 {
@@ -210,9 +210,7 @@ int git_remote_create_with_opts(git_remote **out, const char *url, const git_rem
 	git_str var = GIT_STR_INIT;
 	git_str specbuf = GIT_STR_INIT;
 	const git_remote_create_options dummy_opts = GIT_REMOTE_CREATE_OPTIONS_INIT;
-	char *tmp;
 	int error = -1;
-	bool matched;
 
 	GIT_ASSERT_ARG(out);
 	GIT_ASSERT_ARG(url);
@@ -247,16 +245,13 @@ int git_remote_create_with_opts(git_remote **out, const char *url, const git_rem
 		goto on_error;
 
 	if (opts->repository && !(opts->flags & GIT_REMOTE_CREATE_SKIP_INSTEADOF)) {
-		remote->url = apply_insteadof(&matched, config_ro, canonical_url.ptr, GIT_DIRECTION_FETCH);
-		tmp = apply_insteadof(&matched, config_ro, canonical_url.ptr, GIT_DIRECTION_PUSH);
-		if (matched) {
-			remote->pushurl = tmp;
-			GIT_ERROR_CHECK_ALLOC(remote->pushurl);
-		}
+		if ((error = apply_insteadof(&remote->url, config_ro, canonical_url.ptr, GIT_DIRECTION_FETCH, true)) < 0 ||
+		    (error = apply_insteadof(&remote->pushurl, config_ro, canonical_url.ptr, GIT_DIRECTION_PUSH, false)) < 0)
+			goto on_error;
 	} else {
 		remote->url = git__strdup(canonical_url.ptr);
+		GIT_ERROR_CHECK_ALLOC(remote->url);
 	}
-	GIT_ERROR_CHECK_ALLOC(remote->url);
 
 	if (opts->name != NULL) {
 		remote->name = git__strdup(opts->name);
@@ -464,9 +459,7 @@ int git_remote_lookup(git_remote **out, git_repository *repo, const char *name)
 	git_remote *remote = NULL;
 	git_str buf = GIT_STR_INIT;
 	const char *val;
-	char *tmp;
 	int error = 0;
-	bool matched;
 	git_config *config;
 	struct refspec_cb_data data = { NULL };
 	bool optional_setting_found = false, found;
@@ -507,13 +500,9 @@ int git_remote_lookup(git_remote **out, git_repository *repo, const char *name)
 	remote->download_tags = GIT_REMOTE_DOWNLOAD_TAGS_AUTO;
 
 	if (found && strlen(val) > 0) {
-		remote->url = apply_insteadof(&matched, config, val, GIT_DIRECTION_FETCH);
-		GIT_ERROR_CHECK_ALLOC(remote->url);
-		tmp = apply_insteadof(&matched, config, val, GIT_DIRECTION_PUSH);
-		if (matched) {
-			remote->pushurl = tmp;
-			GIT_ERROR_CHECK_ALLOC(remote->pushurl);
-		}
+		if ((error = apply_insteadof(&remote->url, config, val, GIT_DIRECTION_FETCH, true)) < 0 ||
+		    (error = apply_insteadof(&remote->pushurl, config, val, GIT_DIRECTION_PUSH, false)) < 0)
+			goto cleanup;
 	}
 
 	val = NULL;
@@ -532,11 +521,11 @@ int git_remote_lookup(git_remote **out, git_repository *repo, const char *name)
 	}
 
 	if (found && strlen(val) > 0) {
-		if (remote->pushurl) {
+		if (remote->pushurl)
 			git__free(remote->pushurl);
-		}
-		remote->pushurl = apply_insteadof(&matched, config, val, GIT_DIRECTION_FETCH);
-		GIT_ERROR_CHECK_ALLOC(remote->pushurl);
+
+		if ((error = apply_insteadof(&remote->pushurl, config, val, GIT_DIRECTION_FETCH, true)) < 0)
+			goto cleanup;
 	}
 
 	data.remote = remote;
@@ -2736,7 +2725,7 @@ int git_remote_push(git_remote *remote, const git_strarray *refspecs, const git_
 #define SUFFIX_FETCH "insteadof"
 #define SUFFIX_PUSH "pushinsteadof"
 
-char *apply_insteadof(bool *matched, git_config *config, const char *url, int direction)
+static int apply_insteadof(char **out, git_config *config, const char *url, int direction, bool use_default_if_empty)
 {
 	size_t match_length, prefix_length, suffix_length;
 	char *replacement = NULL;
@@ -2746,11 +2735,10 @@ char *apply_insteadof(bool *matched, git_config *config, const char *url, int di
 	git_config_entry *entry;
 	git_config_iterator *iter;
 
-	GIT_ASSERT_ARG_WITH_RETVAL(config, NULL);
-	GIT_ASSERT_ARG_WITH_RETVAL(url, NULL);
-	GIT_ASSERT_ARG_WITH_RETVAL(direction == GIT_DIRECTION_FETCH || direction == GIT_DIRECTION_PUSH, NULL);
-	GIT_ASSERT_ARG_WITH_RETVAL(matched, NULL);
-	*matched = 0;
+	GIT_ASSERT_ARG(out);
+	GIT_ASSERT_ARG(config);
+	GIT_ASSERT_ARG(url);
+	GIT_ASSERT_ARG(direction == GIT_DIRECTION_FETCH || direction == GIT_DIRECTION_PUSH);
 
 	/* Add 1 to prefix/suffix length due to the additional escaped dot */
 	prefix_length = strlen(PREFIX) + 1;
@@ -2763,7 +2751,7 @@ char *apply_insteadof(bool *matched, git_config *config, const char *url, int di
 	}
 
 	if (git_config_iterator_glob_new(&iter, config, regexp) < 0)
-		return NULL;
+		return -1;
 
 	match_length = 0;
 	while (git_config_next(&entry, iter) == 0) {
@@ -2772,6 +2760,7 @@ char *apply_insteadof(bool *matched, git_config *config, const char *url, int di
 		/* Check if entry value is a prefix of URL */
 		if (git__prefixcmp(url, entry->value))
 			continue;
+
 		/* Check if entry value is longer than previous
 		 * prefixes */
 		if ((n = strlen(entry->value)) <= match_length)
@@ -2789,15 +2778,20 @@ char *apply_insteadof(bool *matched, git_config *config, const char *url, int di
 
 	git_config_iterator_free(iter);
 
-	if (match_length == 0)
-		return git__strdup(url);
+	if (match_length == 0 && use_default_if_empty) {
+		*out = git__strdup(url);
+		return *out ? 0 : -1;
+	} else if (match_length == 0) {
+		*out = NULL;
+		return 0;
+	}
 
 	git_str_printf(&result, "%s%s", replacement, url + match_length);
 
 	git__free(replacement);
 
-	*matched = 1;
-	return result.ptr;
+	*out = git_str_detach(&result);
+	return 0;
 }
 
 /* Deprecated functions */