remote: allow overriding the refspecs for download and fetch

With opportunistic ref updates, git has introduced the concept of having
base refspecs *and* refspecs that are active for a particular fetch.

Let's start by letting the user override the refspecs for download.

10 files changed, 64 insertions, 29 deletions

diff --git a/examples/network/fetch.c b/examples/network/fetch.c
index 8d882095b..ab78fc9bd 100644
--- a/examples/network/fetch.c
+++ b/examples/network/fetch.c
@@ -36,7 +36,7 @@ static void *download(void *ptr)
 	// Download the packfile and index it. This function updates the
 	// amount of received data and the indexer stats which lets you
 	// inform the user about progress.
-	if (git_remote_download(data->remote) < 0) {
+	if (git_remote_download(data->remote, NULL) < 0) {
 		data->ret = -1;
 		goto exit;
 	}
diff --git a/include/git2/remote.h b/include/git2/remote.h
index 055f5e517..b714d3469 100644
--- a/include/git2/remote.h
+++ b/include/git2/remote.h
@@ -306,9 +306,12 @@ GIT_EXTERN(int) git_remote_ls(const git_remote_head ***out,  size_t *size, git_r
  * The .idx file will be created and both it and the packfile with be
  * renamed to their final name.
  *
+ * @param remote the remote
+ * @param refspecs the refspecs to use for this negotiation and
+ * download. Use NULL to use the base refspecs
  * @return 0 or an error code
  */
-GIT_EXTERN(int) git_remote_download(git_remote *remote);
+GIT_EXTERN(int) git_remote_download(git_remote *remote, const git_strarray *refspecs);
 
 /**
  * Check whether the remote is connected
@@ -373,6 +376,8 @@ GIT_EXTERN(int) git_remote_update_tips(
  * disconnect and update the remote-tracking branches.
  *
  * @param remote the remote to fetch from
+ * @param refspecs the refspecs to use for this fetch. Pass NULL to
+ * use the base refspecs.
  * @param signature The identity to use when updating reflogs
  * @param reflog_message The message to insert into the reflogs. If NULL, the
  *								 default is "fetch"
@@ -380,6 +385,7 @@ GIT_EXTERN(int) git_remote_update_tips(
  */
 GIT_EXTERN(int) git_remote_fetch(
 		git_remote *remote,
+		const git_strarray *refspecs,
 		const git_signature *signature,
 		const char *reflog_message);
 
diff --git a/src/clone.c b/src/clone.c
index 43b839003..f18f07611 100644
--- a/src/clone.c
+++ b/src/clone.c
@@ -358,7 +358,7 @@ static int clone_into(git_repository *repo, git_remote *_remote, const git_check
 	git_remote_set_update_fetchhead(remote, 0);
 	git_buf_printf(&reflog_message, "clone: from %s", git_remote_url(remote));
 
-	if ((error = git_remote_fetch(remote, signature, git_buf_cstr(&reflog_message))) != 0)
+	if ((error = git_remote_fetch(remote, NULL, signature, git_buf_cstr(&reflog_message))) != 0)
 		goto cleanup;
 
 	error = checkout_branch(repo, remote, co_opts, branch, signature, git_buf_cstr(&reflog_message));
@@ -553,7 +553,7 @@ static int clone_local_into(git_repository *repo, git_remote *remote, const git_
 
 	git_buf_printf(&reflog_message, "clone: from %s", git_remote_url(remote));
 
-	if ((error = git_remote_fetch(remote, signature, git_buf_cstr(&reflog_message))) != 0)
+	if ((error = git_remote_fetch(remote, NULL, signature, git_buf_cstr(&reflog_message))) != 0)
 		goto cleanup;
 
 	error = checkout_branch(repo, remote, co_opts, branch, signature, git_buf_cstr(&reflog_message));
diff --git a/src/remote.c b/src/remote.c
index dfad946d5..8cf8c0353 100644
--- a/src/remote.c
+++ b/src/remote.c
@@ -21,7 +21,7 @@
 
 static int dwim_refspecs(git_vector *out, git_vector *refspecs, git_vector *refs);
 
-static int add_refspec(git_remote *remote, const char *string, bool is_fetch)
+static int add_refspec_to(git_vector *vector, const char *string, bool is_fetch)
 {
 	git_refspec *spec;
 
@@ -34,7 +34,7 @@ static int add_refspec(git_remote *remote, const char *string, bool is_fetch)
 	}
 
 	spec->push = !is_fetch;
-	if (git_vector_insert(&remote->refspecs, spec) < 0) {
+	if (git_vector_insert(vector, spec) < 0) {
 		git_refspec__free(spec);
 		git__free(spec);
 		return -1;
@@ -43,6 +43,11 @@ static int add_refspec(git_remote *remote, const char *string, bool is_fetch)
 	return 0;
 }
 
+static int add_refspec(git_remote *remote, const char *string, bool is_fetch)
+{
+	return add_refspec_to(&remote->refspecs, string, is_fetch);
+}
+
 static int download_tags_value(git_remote *remote, git_config *cfg)
 {
 	const git_config_entry *ce;
@@ -813,20 +818,37 @@ static int ls_to_vector(git_vector *out, git_remote *remote)
 	return 0;
 }
 
-int git_remote_download(git_remote *remote)
+int git_remote_download(git_remote *remote, const git_strarray *refspecs)
 {
 	int error;
-	git_vector refs;
+	size_t i;
+	git_vector refs, specs, *to_active;
 
 	assert(remote);
 
 	if (ls_to_vector(&refs, remote) < 0)
 		return -1;
 
+	if ((git_vector_init(&specs, 0, NULL)) < 0)
+		goto on_error;
+
+	if (!refspecs) {
+		to_active = &remote->refspecs;
+	} else {
+		for (i = 0; i < refspecs->count; i++) {
+			if ((error = add_refspec_to(&specs, refspecs->strings[i], true)) < 0)
+				goto on_error;
+		}
+
+		to_active = &specs;
+	}
+
 	free_refspecs(&remote->active_refspecs);
 
-	error = dwim_refspecs(&remote->active_refspecs, &remote->refspecs, &refs);
+	error = dwim_refspecs(&remote->active_refspecs, to_active, &refs);
 	git_vector_free(&refs);
+	free_refspecs(&specs);
+	git_vector_free(&specs);
 
 	if (error < 0)
 		return error;
@@ -835,10 +857,17 @@ int git_remote_download(git_remote *remote)
 		return error;
 
 	return git_fetch_download_pack(remote);
+
+on_error:
+	git_vector_free(&refs);
+	free_refspecs(&specs);
+	git_vector_free(&specs);
+	return error;
 }
 
 int git_remote_fetch(
 		git_remote *remote,
+		const git_strarray *refspecs,
 		const git_signature *signature,
 		const char *reflog_message)
 {
@@ -849,7 +878,7 @@ int git_remote_fetch(
 	if ((error = git_remote_connect(remote, GIT_DIRECTION_FETCH)) != 0)
 		return error;
 
-	error = git_remote_download(remote);
+	error = git_remote_download(remote, refspecs);
 
 	/* We don't need to be connected anymore */
 	git_remote_disconnect(remote);
diff --git a/tests/fetchhead/nonetwork.c b/tests/fetchhead/nonetwork.c
index 7b64a6339..c8191c5f5 100644
--- a/tests/fetchhead/nonetwork.c
+++ b/tests/fetchhead/nonetwork.c
@@ -335,7 +335,7 @@ void test_fetchhead_nonetwork__unborn_with_upstream(void)
 	cl_git_pass(git_remote_set_url(remote, cl_fixture("testrepo.git")));
 	cl_git_pass(git_remote_save(remote));
 
-	cl_git_pass(git_remote_fetch(remote, NULL, NULL));
+	cl_git_pass(git_remote_fetch(remote, NULL, NULL, NULL));
 	git_remote_free(remote);
 
 	cl_git_pass(git_repository_fetchhead_foreach(repo, assert_master_for_merge, NULL));
diff --git a/tests/network/fetchlocal.c b/tests/network/fetchlocal.c
index 8809f427d..bf0d0872b 100644
--- a/tests/network/fetchlocal.c
+++ b/tests/network/fetchlocal.c
@@ -36,7 +36,7 @@ void test_network_fetchlocal__complete(void)
 	cl_git_pass(git_remote_create(&origin, repo, GIT_REMOTE_ORIGIN, url));
 	git_remote_set_callbacks(origin, &callbacks);
 	cl_git_pass(git_remote_connect(origin, GIT_DIRECTION_FETCH));
-	cl_git_pass(git_remote_download(origin));
+	cl_git_pass(git_remote_download(origin, NULL));
 	cl_git_pass(git_remote_update_tips(origin, NULL, NULL));
 
 	cl_git_pass(git_reference_list(&refnames, repo));
@@ -74,7 +74,7 @@ void test_network_fetchlocal__partial(void)
 	cl_git_pass(git_remote_create(&origin, repo, GIT_REMOTE_ORIGIN, url));
 	git_remote_set_callbacks(origin, &callbacks);
 	cl_git_pass(git_remote_connect(origin, GIT_DIRECTION_FETCH));
-	cl_git_pass(git_remote_download(origin));
+	cl_git_pass(git_remote_download(origin, NULL));
 	cl_git_pass(git_remote_update_tips(origin, NULL, NULL));
 
 	git_strarray_free(&refnames);
diff --git a/tests/network/remote/local.c b/tests/network/remote/local.c
index f1084fc38..0fbed6024 100644
--- a/tests/network/remote/local.c
+++ b/tests/network/remote/local.c
@@ -125,7 +125,7 @@ void test_network_remote_local__shorthand_fetch_refspec0(void)
 	cl_git_pass(git_remote_add_fetch(remote, refspec));
 	cl_git_pass(git_remote_add_fetch(remote, refspec2));
 
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 
 	cl_git_pass(git_reference_lookup(&ref, repo, "refs/remotes/sloppy/master"));
@@ -147,7 +147,7 @@ void test_network_remote_local__shorthand_fetch_refspec1(void)
 	cl_git_pass(git_remote_add_fetch(remote, refspec));
 	cl_git_pass(git_remote_add_fetch(remote, refspec2));
 
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 
 	cl_git_fail(git_reference_lookup(&ref, repo, "refs/remotes/master"));
@@ -162,7 +162,7 @@ void test_network_remote_local__tagopt(void)
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	git_remote_set_autotag(remote, GIT_REMOTE_DOWNLOAD_TAGS_ALL);
 
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 
 
@@ -181,7 +181,7 @@ void test_network_remote_local__push_to_bare_remote(void)
 	/* Get some commits */
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	cl_git_pass(git_remote_add_fetch(remote, "master:master"));
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 	git_remote_disconnect(remote);
 
@@ -218,7 +218,7 @@ void test_network_remote_local__push_to_bare_remote_with_file_url(void)
 	/* Get some commits */
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	cl_git_pass(git_remote_add_fetch(remote, "master:master"));
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 	git_remote_disconnect(remote);
 
@@ -258,7 +258,7 @@ void test_network_remote_local__push_to_non_bare_remote(void)
 	/* Get some commits */
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	cl_git_pass(git_remote_add_fetch(remote, "master:master"));
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 	git_remote_disconnect(remote);
 
@@ -299,7 +299,7 @@ void test_network_remote_local__fetch(void)
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	cl_git_pass(git_remote_add_fetch(remote, refspec));
 
-	cl_git_pass(git_remote_fetch(remote, sig, "UPDAAAAAATE!!"));
+	cl_git_pass(git_remote_fetch(remote, NULL, sig, "UPDAAAAAATE!!"));
 
 	cl_git_pass(git_reference_lookup(&ref, repo, "refs/remotes/sloppy/master"));
 	git_reference_free(ref);
@@ -327,7 +327,7 @@ void test_network_remote_local__reflog(void)
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	cl_git_pass(git_remote_add_fetch(remote, refspec));
 
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, sig, "UPDAAAAAATE!!"));
 
 	cl_git_pass(git_reflog_read(&log, repo, "refs/remotes/sloppy/master"));
@@ -354,7 +354,7 @@ void test_network_remote_local__fetch_default_reflog_message(void)
 	connect_to_local_repository(cl_fixture("testrepo.git"));
 	cl_git_pass(git_remote_add_fetch(remote, refspec));
 
-	cl_git_pass(git_remote_fetch(remote, sig, NULL));
+	cl_git_pass(git_remote_fetch(remote, NULL, sig, NULL));
 
 	cl_git_pass(git_reflog_read(&log, repo, "refs/remotes/sloppy/master"));
 	cl_assert_equal_i(1, git_reflog_entrycount(log));
diff --git a/tests/online/fetch.c b/tests/online/fetch.c
index f03a6faa6..ce92ee82b 100644
--- a/tests/online/fetch.c
+++ b/tests/online/fetch.c
@@ -47,7 +47,7 @@ static void do_fetch(const char *url, git_remote_autotag_option_t flag, int n)
 	git_remote_set_callbacks(remote, &callbacks);
 	git_remote_set_autotag(remote, flag);
 	cl_git_pass(git_remote_connect(remote, GIT_DIRECTION_FETCH));
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 	git_remote_disconnect(remote);
 	cl_assert_equal_i(counter, n);
@@ -86,11 +86,11 @@ void test_online_fetch__fetch_twice(void)
 	git_remote *remote;
 	cl_git_pass(git_remote_create(&remote, _repo, "test", "git://github.com/libgit2/TestGitRepository.git"));
     	cl_git_pass(git_remote_connect(remote, GIT_DIRECTION_FETCH));
-    	cl_git_pass(git_remote_download(remote));
+    	cl_git_pass(git_remote_download(remote, NULL));
     	git_remote_disconnect(remote);
     	
     	git_remote_connect(remote, GIT_DIRECTION_FETCH);
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	git_remote_disconnect(remote);
 	
 	git_remote_free(remote);
@@ -128,7 +128,7 @@ void test_online_fetch__doesnt_retrieve_a_pack_when_the_repository_is_up_to_date
 	callbacks.transfer_progress = &transferProgressCallback;
 	callbacks.payload = &invoked;
 	git_remote_set_callbacks(remote, &callbacks);
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 
 	cl_assert_equal_i(false, invoked);
 
@@ -162,7 +162,7 @@ void test_online_fetch__can_cancel(void)
 	git_remote_set_callbacks(remote, &callbacks);
 
 	cl_git_pass(git_remote_connect(remote, GIT_DIRECTION_FETCH));
-	cl_git_fail_with(git_remote_download(remote), -4321);
+	cl_git_fail_with(git_remote_download(remote, NULL), -4321);
 	git_remote_disconnect(remote);
 	git_remote_free(remote);
 }
diff --git a/tests/online/fetchhead.c b/tests/online/fetchhead.c
index 3f27e1331..f6b9ab0af 100644
--- a/tests/online/fetchhead.c
+++ b/tests/online/fetchhead.c
@@ -50,7 +50,7 @@ static void fetchhead_test_fetch(const char *fetchspec, const char *expected_fet
 	}
 
 	cl_git_pass(git_remote_connect(remote, GIT_DIRECTION_FETCH));
-	cl_git_pass(git_remote_download(remote));
+	cl_git_pass(git_remote_download(remote, NULL));
 	cl_git_pass(git_remote_update_tips(remote, NULL, NULL));
 	git_remote_disconnect(remote);
 	git_remote_free(remote);
diff --git a/tests/online/push.c b/tests/online/push.c
index 70ec705fe..b09c7ad1f 100644
--- a/tests/online/push.c
+++ b/tests/online/push.c
@@ -408,7 +408,7 @@ void test_online_push__initialize(void)
 
 	/* Now that we've deleted everything, fetch from the remote */
 	cl_git_pass(git_remote_connect(_remote, GIT_DIRECTION_FETCH));
-	cl_git_pass(git_remote_download(_remote));
+	cl_git_pass(git_remote_download(_remote, NULL));
 	cl_git_pass(git_remote_update_tips(_remote, NULL, NULL));
 	git_remote_disconnect(_remote);
 }