thodg/libgit2

diff --git a/include/git2/remote.h b/include/git2/remote.h
index 6471acc..23405ac 100644
--- a/include/git2/remote.h
+++ b/include/git2/remote.h
@@ -336,6 +336,24 @@ GIT_EXTERN(int) git_remote_autotag(git_remote *remote);
  */
 GIT_EXTERN(void) git_remote_set_autotag(git_remote *remote, int value);
 
+/**
+ * Give the remote a new name
+ *
+ * All remote-tracking branches and configuration settings
+ * for the remote are updated.
+ *
+ * @param remote the remote to rename
+ * @param new_name the new name the remote should bear
+ * @param callback Optional callback to notify the consumer of fetch refspecs
+ * that haven't been automatically updated and need potential manual tweaking.
+ * @param payload Additional data to pass to the callback
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_remote_rename(
+	git_remote *remote,
+	const char *new_name,
+	int (*callback)(const char *problematic_refspec, void *payload),
+	void *payload);
 
 /** @} */
 GIT_END_DECL
diff --git a/src/remote.c b/src/remote.c
index 3506d5f..559d71d 100644
--- a/src/remote.c
+++ b/src/remote.c
@@ -798,3 +798,288 @@ void git_remote_set_autotag(git_remote *remote, int value)
 {
 	remote->download_tags = value;
 }
+
+static int ensure_remote_doesnot_exist(git_repository *repo, const char *name)
+{
+	int error;
+	git_remote *remote;
+
+	error = git_remote_load(&remote, repo, name);
+
+	if (error == GIT_ENOTFOUND)
+		return 0;
+
+	if (error < 0)
+		return error;
+
+	git_remote_free(remote);
+
+	giterr_set(
+		GITERR_CONFIG,
+		"Remote '%s' already exists.", name);
+
+	return GIT_EEXISTS;
+}
+
+static int rename_remote_config_section(
+	git_repository *repo,
+	const char *old_name,
+	const char *new_name)
+{
+	git_buf old_section_name = GIT_BUF_INIT,
+		new_section_name = GIT_BUF_INIT;
+	int error = -1;
+
+	if (git_buf_printf(&old_section_name, "remote.%s", old_name) < 0)
+		goto cleanup;
+
+	if (git_buf_printf(&new_section_name, "remote.%s", new_name) < 0)
+		goto cleanup;
+
+	error = git_config_rename_section(
+		repo,
+		git_buf_cstr(&old_section_name),
+		git_buf_cstr(&new_section_name));
+
+cleanup:
+	git_buf_free(&old_section_name);
+	git_buf_free(&new_section_name);
+
+	return error;
+}
+
+struct update_data
+{
+	git_config *config;
+	const char *old_remote_name;
+	const char *new_remote_name;
+};
+
+static int update_config_entries_cb(
+	const git_config_entry *entry,
+	void *payload)
+{
+	struct update_data *data = (struct update_data *)payload;
+
+	if (strcmp(entry->value, data->old_remote_name))
+		return 0;
+
+	return git_config_set_string(
+		data->config,
+		entry->name,
+		data->new_remote_name);
+}
+
+static int update_branch_remote_config_entry(
+	git_repository *repo,
+	const char *old_name,
+	const char *new_name)
+{
+	git_config *config;
+	struct update_data data;
+
+	if (git_repository_config__weakptr(&config, repo) < 0)
+		return -1;
+
+	data.config = config;
+	data.old_remote_name = old_name;
+	data.new_remote_name = new_name;
+
+	return git_config_foreach_match(
+		config,
+		"branch\\..+\\.remote",
+		update_config_entries_cb, &data);
+}
+
+static int rename_cb(const char *ref, void *data)
+{
+	if (git__prefixcmp(ref, GIT_REFS_REMOTES_DIR))
+		return 0;
+	
+	return git_vector_insert((git_vector *)data, git__strdup(ref));
+}
+
+static int rename_one_remote_reference(
+	git_repository *repo,
+	const char *reference_name,
+	const char *old_remote_name,
+	const char *new_remote_name)
+{
+	int error;
+	git_buf new_name = GIT_BUF_INIT;
+	git_reference *reference = NULL;
+
+	if (git_buf_printf(
+		&new_name,
+		GIT_REFS_REMOTES_DIR "%s%s",
+		new_remote_name,
+		reference_name + strlen(GIT_REFS_REMOTES_DIR) + strlen(old_remote_name)) < 0)
+			return -1;
+
+	if (git_reference_lookup(&reference, repo, reference_name) < 0)
+		goto cleanup;
+
+	error = git_reference_rename(reference, git_buf_cstr(&new_name), 0);
+
+cleanup:
+	git_reference_free(reference);
+	git_buf_free(&new_name);
+	return error;
+}
+
+static int rename_remote_references(
+	git_repository *repo,
+	const char *old_name,
+	const char *new_name)
+{
+	git_vector refnames;
+	int error = -1;
+	unsigned int i;
+	char *name;
+
+	if (git_vector_init(&refnames, 8, NULL) < 0)
+		goto cleanup;
+
+	if (git_reference_foreach(
+		repo,
+		GIT_REF_LISTALL,
+		rename_cb,
+		&refnames) < 0)
+			goto cleanup;
+
+	git_vector_foreach(&refnames, i, name) {
+		if ((error = rename_one_remote_reference(repo, name, old_name, new_name)) < 0)
+			goto cleanup;
+	}
+
+	error = 0;
+cleanup:
+	git_vector_foreach(&refnames, i, name) {
+		git__free(name);
+	}
+
+	git_vector_free(&refnames);
+	return error;
+}
+
+static int rename_fetch_refspecs(
+	git_remote *remote,
+	const char *new_name,
+	int (*callback)(const char *problematic_refspec, void *payload),
+	void *payload)
+{
+	git_config *config;
+	const git_refspec *fetch_refspec;
+	git_buf dst_prefix = GIT_BUF_INIT, serialized = GIT_BUF_INIT;
+	const char* pos;
+	int error = -1;
+
+	fetch_refspec = git_remote_fetchspec(remote);
+
+	/* Is there a refspec to deal with? */
+	if (fetch_refspec->src == NULL &&
+		fetch_refspec->dst == NULL)
+		return 0;
+
+	if (git_refspec__serialize(&serialized, fetch_refspec) < 0)
+		goto cleanup;
+
+	/* Is it an in-memory remote? */
+	if (remote->name == '\0') {
+		error = (callback(git_buf_cstr(&serialized), payload) < 0) ? GIT_EUSER : 0;
+		goto cleanup;
+	}
+
+	if (git_buf_printf(&dst_prefix, ":refs/remotes/%s/", remote->name) < 0)
+		goto cleanup;
+
+	pos = strstr(git_buf_cstr(&serialized), git_buf_cstr(&dst_prefix));
+
+	/* Does the dst part of the refspec follow the extected standard format? */
+	if (!pos) {
+		error = (callback(git_buf_cstr(&serialized), payload) < 0) ? GIT_EUSER : 0;
+		goto cleanup;
+	}
+
+	if (git_buf_splice(
+		&serialized,
+		pos - git_buf_cstr(&serialized) + strlen(":refs/remotes/"),
+		strlen(remote->name), new_name,
+		strlen(new_name)) < 0)
+			goto cleanup;
+
+	git_refspec__free(&remote->fetch);
+
+	if (git_refspec__parse(&remote->fetch, git_buf_cstr(&serialized), true) < 0)
+		goto cleanup;
+
+	if (git_repository_config__weakptr(&config, remote->repo) < 0)
+		goto cleanup;
+
+	error = update_config_refspec(config, new_name, &remote->fetch, GIT_DIR_FETCH);
+
+cleanup:
+	git_buf_free(&serialized);
+	git_buf_free(&dst_prefix);
+	return error;
+}
+
+int git_remote_rename(
+	git_remote *remote,
+	const char *new_name,
+	int (*callback)(const char *problematic_refspec, void *payload),
+	void *payload)
+{
+	int error;
+
+	assert(remote && new_name);
+
+	if ((error = ensure_remote_doesnot_exist(remote->repo, new_name)) < 0)
+		return error;
+
+	if ((error = ensure_remote_name_is_valid(new_name)) < 0)
+		return error;
+
+	if (!remote->name) {
+		if ((error = rename_fetch_refspecs(
+			remote,
+			new_name,
+			callback,
+			payload)) < 0)
+			return error;
+
+		remote->name = git__strdup(new_name);
+
+		return git_remote_save(remote);
+	}
+
+	if ((error = rename_remote_config_section(
+		remote->repo,
+		remote->name,
+		new_name)) < 0)
+			return error;
+
+	if ((error = update_branch_remote_config_entry(
+		remote->repo,
+		remote->name,
+		new_name)) < 0)
+			return error;
+
+	if ((error = rename_remote_references(
+		remote->repo,
+		remote->name,
+		new_name)) < 0)
+			return error;
+
+	if ((error = rename_fetch_refspecs(
+		remote,
+		new_name,
+		callback,
+		payload)) < 0)
+		return error;
+
+	git__free(remote->name);
+	remote->name = git__strdup(new_name);
+
+	return 0;
+}
diff --git a/tests-clar/config/config_helpers.c b/tests-clar/config/config_helpers.c
index 652f80f..53bd945 100644
--- a/tests-clar/config/config_helpers.c
+++ b/tests-clar/config/config_helpers.c
@@ -20,3 +20,18 @@ void assert_config_entry_existence(
 	else
 		cl_assert_equal_i(GIT_ENOTFOUND, result);
 }
+
+void assert_config_entry_value(
+	git_repository *repo,
+	const char *name,
+	const char *expected_value)
+{
+	git_config *config;
+	const char *out;
+
+	cl_git_pass(git_repository_config__weakptr(&config, repo));
+
+	cl_git_pass(git_config_get_string(&out, config, name));
+
+	cl_assert_equal_s(expected_value, out);
+}
diff --git a/tests-clar/config/config_helpers.h b/tests-clar/config/config_helpers.h
index d18c6c3..b887b3d 100644
--- a/tests-clar/config/config_helpers.h
+++ b/tests-clar/config/config_helpers.h
@@ -2,3 +2,8 @@ extern void assert_config_entry_existence(
 	git_repository *repo,
 	const char *name,
 	bool is_supposed_to_exist);
+
+extern void assert_config_entry_value(
+	git_repository *repo,
+	const char *name,
+	const char *expected_value);
diff --git a/tests-clar/network/remoterename.c b/tests-clar/network/remoterename.c
new file mode 100644
index 0000000..70041f4
--- /dev/null
+++ b/tests-clar/network/remoterename.c
@@ -0,0 +1,201 @@
+#include "clar_libgit2.h"
+#include "config/config_helpers.h"
+
+#include "repository.h"
+
+static git_remote *_remote;
+static git_repository *_repo;
+
+void test_network_remoterename__initialize(void)
+{
+	_repo = cl_git_sandbox_init("testrepo.git");
+
+	cl_git_pass(git_remote_load(&_remote, _repo, "test"));
+}
+
+void test_network_remoterename__cleanup(void)
+{
+	git_remote_free(_remote);
+
+	cl_git_sandbox_cleanup();
+}
+
+static int dont_call_me_cb(const char *fetch_refspec, void *payload)
+{
+	GIT_UNUSED(fetch_refspec);
+	GIT_UNUSED(payload);
+
+	cl_assert(false);
+
+	return -1;
+}
+
+void test_network_remoterename__renaming_a_remote_moves_related_configuration_section(void)
+{
+	assert_config_entry_existence(_repo, "remote.test.fetch", true);
+	assert_config_entry_existence(_repo, "remote.just/renamed.fetch", false);
+
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", dont_call_me_cb, NULL));
+
+	assert_config_entry_existence(_repo, "remote.test.fetch", false);
+	assert_config_entry_existence(_repo, "remote.just/renamed.fetch", true);
+}
+
+void test_network_remoterename__renaming_a_remote_updates_branch_related_configuration_entries(void)
+{
+	assert_config_entry_value(_repo, "branch.master.remote", "test");
+
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", dont_call_me_cb, NULL));
+
+	assert_config_entry_value(_repo, "branch.master.remote", "just/renamed");
+}
+
+void test_network_remoterename__renaming_a_remote_updates_default_fetchrefspec(void)
+{
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", dont_call_me_cb, NULL));
+
+	assert_config_entry_value(_repo, "remote.just/renamed.fetch", "+refs/heads/*:refs/remotes/just/renamed/*");
+}
+
+void test_network_remoterename__renaming_a_remote_without_a_fetchrefspec_doesnt_create_one(void)
+{
+	git_config *config;
+
+	git_remote_free(_remote);
+	cl_git_pass(git_repository_config__weakptr(&config, _repo));
+	cl_git_pass(git_config_delete(config, "remote.test.fetch"));
+
+	cl_git_pass(git_remote_load(&_remote, _repo, "test"));
+
+	assert_config_entry_existence(_repo, "remote.test.fetch", false);
+
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", dont_call_me_cb, NULL));
+
+	assert_config_entry_existence(_repo, "remote.just/renamed.fetch", false);
+}
+
+static int ensure_refspecs(const char* refspec_name, void *payload)
+{
+	int i = 0;
+	bool found = false;
+	const char ** exp = (const char **)payload;
+
+	while (exp[i]) {
+		if (strcmp(exp[i++], refspec_name))
+			continue;
+
+		found = true;
+		break;
+	}
+
+	cl_assert(found);
+
+	return 0;
+}
+
+void test_network_remoterename__renaming_a_remote_notifies_of_non_default_fetchrefspec(void)
+{
+	git_config *config;
+
+	char *expected_refspecs[] = {
+		"+refs/*:refs/*",
+		NULL
+	};
+
+	git_remote_free(_remote);
+	cl_git_pass(git_repository_config__weakptr(&config, _repo));
+	cl_git_pass(git_config_set_string(config, "remote.test.fetch", "+refs/*:refs/*"));
+	cl_git_pass(git_remote_load(&_remote, _repo, "test"));
+
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", ensure_refspecs, &expected_refspecs));
+
+	assert_config_entry_value(_repo, "remote.just/renamed.fetch", "+refs/*:refs/*");
+}
+
+void test_network_remoterename__new_name_can_contain_dots(void)
+{
+	cl_git_pass(git_remote_rename(_remote, "just.renamed", dont_call_me_cb, NULL));
+	cl_assert_equal_s("just.renamed", git_remote_name(_remote));
+}
+
+void test_network_remoterename__new_name_must_conform_to_reference_naming_conventions(void)
+{
+	cl_git_fail(git_remote_rename(_remote, "new@{name", dont_call_me_cb, NULL));
+}
+
+void test_network_remoterename__renamed_name_is_persisted(void)
+{
+	git_remote *renamed;
+	git_repository *another_repo;
+
+	cl_git_fail(git_remote_load(&renamed, _repo, "just/renamed"));
+
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", dont_call_me_cb, NULL));
+
+	cl_git_pass(git_repository_open(&another_repo, "testrepo.git"));
+	cl_git_pass(git_remote_load(&renamed, _repo, "just/renamed"));
+
+	git_remote_free(renamed);
+	git_repository_free(another_repo);
+}
+
+void test_network_remoterename__cannot_overwrite_an_existing_remote(void)
+{
+	cl_assert_equal_i(GIT_EEXISTS, git_remote_rename(_remote, "test", dont_call_me_cb, NULL));
+	cl_assert_equal_i(GIT_EEXISTS, git_remote_rename(_remote, "test_with_pushurl", dont_call_me_cb, NULL));
+}
+
+void test_network_remoterename__renaming_an_inmemory_remote_persists_it(void)
+{
+	git_remote *remote;
+
+	assert_config_entry_existence(_repo, "remote.durable.url", false);
+
+	cl_git_pass(git_remote_new(&remote, _repo, NULL, "git://github.com/libgit2/durable.git", NULL));
+
+	assert_config_entry_existence(_repo, "remote.durable.url", false);
+
+	cl_git_pass(git_remote_rename(remote, "durable", dont_call_me_cb, NULL));
+
+	assert_config_entry_value(_repo, "remote.durable.url", "git://github.com/libgit2/durable.git");
+
+	git_remote_free(remote);
+}
+
+void test_network_remoterename__renaming_an_inmemory_nameless_remote_notifies_the_inability_to_update_the_fetch_refspec(void)
+{
+	git_remote *remote;
+
+	char *expected_refspecs[] = {
+		"+refs/heads/*:refs/remotes/volatile/*",
+		NULL
+	};
+
+	assert_config_entry_existence(_repo, "remote.volatile.url", false);
+
+	cl_git_pass(git_remote_new(
+		&remote,
+		_repo,
+		NULL,
+		"git://github.com/libgit2/volatile.git",
+		"+refs/heads/*:refs/remotes/volatile/*"));
+
+	cl_git_pass(git_remote_rename(remote, "durable", ensure_refspecs, &expected_refspecs));
+
+	git_remote_free(remote);
+}
+
+void test_network_remoterename__renaming_a_remote_moves_the_underlying_reference(void)
+{
+	git_reference *underlying;
+
+	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&underlying, _repo, "refs/remotes/just/renamed"));
+	cl_git_pass(git_reference_lookup(&underlying, _repo, "refs/remotes/test/master"));
+	git_reference_free(underlying);
+
+	cl_git_pass(git_remote_rename(_remote, "just/renamed", dont_call_me_cb, NULL));
+
+	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&underlying, _repo, "refs/remotes/test/master"));
+	cl_git_pass(git_reference_lookup(&underlying, _repo, "refs/remotes/just/renamed/master"));
+	git_reference_free(underlying);
+}