thodg/libgit2

diff --git a/include/git2/branch.h b/include/git2/branch.h
index 44d6fd9..851de29 100644
--- a/include/git2/branch.h
+++ b/include/git2/branch.h
@@ -200,25 +200,20 @@ GIT_EXTERN(int) git_branch_set_upstream(git_reference *branch, const char *upstr
  * Return the name of the reference supporting the remote tracking branch,
  * given the name of a local branch reference.
  *
- * @param tracking_branch_name_out The user-allocated buffer which will be
- *     filled with the name of the reference. Pass NULL if you just want to
- *     get the needed size of the name of the reference as the output value.
- *
- * @param buffer_size Size of the `out` buffer in bytes.
+ * @param out Pointer to the user-allocated git_buf which will be
+ * filled with the name of the reference.
  *
  * @param repo the repository where the branches live
  *
- * @param canonical_branch_name name of the local branch.
+ * @param refname reference name of the local branch.
  *
- * @return number of characters in the reference name
- *     including the trailing NUL byte; GIT_ENOTFOUND when no remote tracking
- *     reference exists, otherwise an error code.
+ * @return 0, GIT_ENOTFOUND when no remote tracking reference exists,
+ *     otherwise an error code.
  */
 GIT_EXTERN(int) git_branch_upstream_name(
-	char *tracking_branch_name_out,
-	size_t buffer_size,
+	git_buf *out,
 	git_repository *repo,
-	const char *canonical_branch_name);
+	const char *refname);
 
 /**
  * Determine if the current local branch is pointed at by HEAD.
@@ -234,25 +229,19 @@ GIT_EXTERN(int) git_branch_is_head(
 /**
  * Return the name of remote that the remote tracking branch belongs to.
  *
- * @param remote_name_out The user-allocated buffer which will be
- *     filled with the name of the remote. Pass NULL if you just want to
- *     get the needed size of the name of the remote as the output value.
- *
- * @param buffer_size Size of the `out` buffer in bytes.
+ * @param out Pointer to the user-allocated git_buf which will be filled iwth the name of the remote.
  *
  * @param repo The repository where the branch lives.
  *
  * @param canonical_branch_name name of the remote tracking branch.
  *
- * @return Number of characters in the reference name
- *     including the trailing NUL byte; GIT_ENOTFOUND
+ * @return 0, GIT_ENOTFOUND
  *     when no remote matching remote was found,
  *     GIT_EAMBIGUOUS when the branch maps to several remotes,
  *     otherwise an error code.
  */
 GIT_EXTERN(int) git_branch_remote_name(
-	char *remote_name_out,
-	size_t buffer_size,
+	git_buf *out,
 	git_repository *repo,
 	const char *canonical_branch_name);
 
diff --git a/src/branch.c b/src/branch.c
index 3b9aa0d..a702c66 100644
--- a/src/branch.c
+++ b/src/branch.c
@@ -286,10 +286,10 @@ static int retrieve_upstream_configuration(
 	return error;
 }
 
-int git_branch_upstream__name(
-	git_buf *tracking_name,
+int git_branch_upstream_name(
+	git_buf *out,
 	git_repository *repo,
-	const char *canonical_branch_name)
+	const char *refname)
 {
 	const char *remote_name, *merge_name;
 	git_buf buf = GIT_BUF_INIT;
@@ -297,22 +297,24 @@ int git_branch_upstream__name(
 	git_remote *remote = NULL;
 	const git_refspec *refspec;
 
-	assert(tracking_name && canonical_branch_name);
+	assert(out && refname);
+
+	git_buf_sanitize(out);
 
-	if (!git_reference__is_branch(canonical_branch_name))
-		return not_a_local_branch(canonical_branch_name);
+	if (!git_reference__is_branch(refname))
+		return not_a_local_branch(refname);
 
 	if ((error = retrieve_upstream_configuration(
-		&remote_name, repo, canonical_branch_name, "branch.%s.remote")) < 0)
+		&remote_name, repo, refname, "branch.%s.remote")) < 0)
 			goto cleanup;
 
 	if ((error = retrieve_upstream_configuration(
-		&merge_name, repo, canonical_branch_name, "branch.%s.merge")) < 0)
+		&merge_name, repo, refname, "branch.%s.merge")) < 0)
 			goto cleanup;
 
 	if (!*remote_name || !*merge_name) {
 		giterr_set(GITERR_REFERENCE,
-			"branch '%s' does not have an upstream", canonical_branch_name);
+			"branch '%s' does not have an upstream", refname);
 		error = GIT_ENOTFOUND;
 		goto cleanup;
 	}
@@ -333,7 +335,7 @@ int git_branch_upstream__name(
 		if (git_buf_sets(&buf, merge_name) < 0)
 			goto cleanup;
 
-	error = git_buf_set(tracking_name, git_buf_cstr(&buf), git_buf_len(&buf));
+	error = git_buf_set(out, git_buf_cstr(&buf), git_buf_len(&buf));
 
 cleanup:
 	git_remote_free(remote);
@@ -341,7 +343,7 @@ cleanup:
 	return error;
 }
 
-static int remote_name(git_buf *buf, git_repository *repo, const char *canonical_branch_name)
+int git_branch_remote_name(git_buf *buf, git_repository *repo, const char *refname)
 {
 	git_strarray remote_list = {0};
 	size_t i;
@@ -350,12 +352,14 @@ static int remote_name(git_buf *buf, git_repository *repo, const char *canonical
 	int error = 0;
 	char *remote_name = NULL;
 
-	assert(buf && repo && canonical_branch_name);
+	assert(buf && repo && refname);
+
+	git_buf_sanitize(buf);
 
 	/* Verify that this is a remote branch */
-	if (!git_reference__is_remote(canonical_branch_name)) {
+	if (!git_reference__is_remote(refname)) {
 		giterr_set(GITERR_INVALID, "Reference '%s' is not a remote branch.",
-			canonical_branch_name);
+			refname);
 		error = GIT_ERROR;
 		goto cleanup;
 	}
@@ -369,7 +373,7 @@ static int remote_name(git_buf *buf, git_repository *repo, const char *canonical
 		if ((error = git_remote_load(&remote, repo, remote_list.strings[i])) < 0)
 			continue;
 
-		fetchspec = git_remote__matching_dst_refspec(remote, canonical_branch_name);
+		fetchspec = git_remote__matching_dst_refspec(remote, refname);
 		if (fetchspec) {
 			/* If we have not already set out yet, then set
 			 * it to the matching remote name. Otherwise
@@ -381,7 +385,7 @@ static int remote_name(git_buf *buf, git_repository *repo, const char *canonical
 				git_remote_free(remote);
 
 				giterr_set(GITERR_REFERENCE,
-					"Reference '%s' is ambiguous", canonical_branch_name);
+					"Reference '%s' is ambiguous", refname);
 				error = GIT_EAMBIGUOUS;
 				goto cleanup;
 			}
@@ -395,68 +399,18 @@ static int remote_name(git_buf *buf, git_repository *repo, const char *canonical
 		error = git_buf_puts(buf, remote_name);
 	} else {
 		giterr_set(GITERR_REFERENCE,
-			"Could not determine remote for '%s'", canonical_branch_name);
+			"Could not determine remote for '%s'", refname);
 		error = GIT_ENOTFOUND;
 	}
 
 cleanup:
+	if (error < 0)
+		git_buf_free(buf);
+
 	git_strarray_free(&remote_list);
 	return error;
 }
 
-int git_branch_remote_name(char *buffer, size_t buffer_len, git_repository *repo, const char *refname)
-{
-	int ret;
-	git_buf buf = GIT_BUF_INIT;
-
-	if ((ret = remote_name(&buf, repo, refname)) < 0)
-		return ret;
-
-	if (buffer)
-		git_buf_copy_cstr(buffer, buffer_len, &buf);
-
-	ret = (int)git_buf_len(&buf) + 1;
-	git_buf_free(&buf);
-
-	return ret;
-}
-
-int git_branch_upstream_name(
-	char *tracking_branch_name_out,
-	size_t buffer_size,
-	git_repository *repo,
-	const char *canonical_branch_name)
-{
-	git_buf buf = GIT_BUF_INIT;
-	int error;
-
-	assert(canonical_branch_name);
-
-	if (tracking_branch_name_out && buffer_size)
-		*tracking_branch_name_out = '\0';
-
-	if ((error = git_branch_upstream__name(
-		&buf, repo, canonical_branch_name)) < 0)
-			goto cleanup;
-
-	if (tracking_branch_name_out && buf.size + 1 > buffer_size) { /* +1 for NUL byte */
-		giterr_set(
-			GITERR_INVALID,
-			"Buffer too short to hold the tracked reference name.");
-		error = -1;
-		goto cleanup;
-	}
-
-	if (tracking_branch_name_out)
-		git_buf_copy_cstr(tracking_branch_name_out, buffer_size, &buf);
-
-	error = (int)buf.size + 1;
-
-cleanup:
-	git_buf_free(&buf);
-	return (int)error;
-}
-
 int git_branch_upstream(
 		git_reference **tracking_out,
 		git_reference *branch)
@@ -464,7 +418,7 @@ int git_branch_upstream(
 	int error;
 	git_buf tracking_name = GIT_BUF_INIT;
 
-	if ((error = git_branch_upstream__name(&tracking_name,
+	if ((error = git_branch_upstream_name(&tracking_name,
 		git_reference_owner(branch), git_reference_name(branch))) < 0)
 			return error;
 
@@ -547,7 +501,7 @@ int git_branch_set_upstream(git_reference *branch, const char *upstream_name)
 	if (local)
 		git_buf_puts(&value, ".");
 	else
-		remote_name(&value, repo, git_reference_name(upstream));
+		git_branch_remote_name(&value, repo, git_reference_name(upstream));
 
 	if (git_buf_printf(&key, "branch.%s.remote", shortname) < 0)
 		goto on_error;
diff --git a/tests/clone/empty.c b/tests/clone/empty.c
index 6d19244..78aef7d 100644
--- a/tests/clone/empty.c
+++ b/tests/clone/empty.c
@@ -38,7 +38,7 @@ void test_clone_empty__can_clone_an_empty_local_repo_barely(void)
 	char *local_name = "refs/heads/master";
 	const char *expected_tracked_branch_name = "refs/remotes/origin/master";
 	const char *expected_remote_name = "origin";
-	char buffer[1024];
+	git_buf buf = GIT_BUF_INIT;
 	git_reference *ref;
 
 	cl_set_cleanup(&cleanup_repository, "./empty");
@@ -50,16 +50,14 @@ void test_clone_empty__can_clone_an_empty_local_repo_barely(void)
 	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&ref, g_repo_cloned, local_name));
 
 	/* ...one can still retrieve the name of the remote tracking reference */
-	cl_assert_equal_i((int)strlen(expected_tracked_branch_name) + 1,
-		git_branch_upstream_name(buffer, 1024, g_repo_cloned, local_name));
+	cl_git_pass(git_branch_upstream_name(&buf, g_repo_cloned, local_name));
 
-	cl_assert_equal_s(expected_tracked_branch_name, buffer);
+	cl_assert_equal_s(expected_tracked_branch_name, buf.ptr);
 
 	/* ...and the name of the remote... */
-	cl_assert_equal_i((int)strlen(expected_remote_name) + 1,
-		git_branch_remote_name(buffer, 1024, g_repo_cloned, expected_tracked_branch_name));
+	cl_git_pass(git_branch_remote_name(&buf, g_repo_cloned, expected_tracked_branch_name));
 
-	cl_assert_equal_s(expected_remote_name, buffer);
+	cl_assert_equal_s(expected_remote_name, buf.ptr);
 
 	/* ...even when the remote HEAD is unborn as well */
 	cl_assert_equal_i(GIT_ENOTFOUND, git_reference_lookup(&ref, g_repo_cloned,
diff --git a/tests/refs/branches/remote.c b/tests/refs/branches/remote.c
index c110adb..bac0884 100644
--- a/tests/refs/branches/remote.c
+++ b/tests/refs/branches/remote.c
@@ -21,53 +21,40 @@ void test_refs_branches_remote__cleanup(void)
 
 void test_refs_branches_remote__can_get_remote_for_branch(void)
 {
-	char remotename[1024] = {0};
+	git_buf remotename = {0};
 
-	cl_assert_equal_i(expected_remote_name_length,
-		git_branch_remote_name(NULL, 0, g_repo, remote_tracking_branch_name));
+	cl_git_pass(git_branch_remote_name(&remotename, g_repo, remote_tracking_branch_name));
 
-	cl_assert_equal_i(expected_remote_name_length,
-		git_branch_remote_name(remotename, expected_remote_name_length, g_repo,
-			remote_tracking_branch_name));
-
-	cl_assert_equal_s("test", remotename);
-}
-
-void test_refs_branches_remote__insufficient_buffer_returns_error(void)
-{
-	char remotename[1024] = {0};
-
-	cl_assert_equal_i(expected_remote_name_length,
-		git_branch_remote_name(NULL, 0, g_repo, remote_tracking_branch_name));
-
-	cl_git_fail_with(git_branch_remote_name(remotename,
-		expected_remote_name_length - 1, g_repo, remote_tracking_branch_name),
-			expected_remote_name_length);
+	cl_assert_equal_s("test", remotename.ptr);
+	git_buf_free(&remotename);
 }
 
 void test_refs_branches_remote__no_matching_remote_returns_error(void)
 {
 	const char *unknown = "refs/remotes/nonexistent/master";
+	git_buf buf;
 
 	giterr_clear();
-	cl_git_fail_with(git_branch_remote_name(
-		NULL, 0, g_repo, unknown), GIT_ENOTFOUND);
+	memset(&buf, 0, sizeof(git_buf));
+	cl_git_fail_with(git_branch_remote_name(&buf, g_repo, unknown), GIT_ENOTFOUND);
 	cl_assert(giterr_last() != NULL);
 }
 
 void test_refs_branches_remote__local_remote_returns_error(void)
 {
 	const char *local = "refs/heads/master";
+	git_buf buf;
 
 	giterr_clear();
-	cl_git_fail_with(git_branch_remote_name(
-		NULL, 0, g_repo, local), GIT_ERROR);
+	memset(&buf, 0, sizeof(git_buf));
+	cl_git_fail_with(git_branch_remote_name(&buf, g_repo, local), GIT_ERROR);
 	cl_assert(giterr_last() != NULL);
 }
 
 void test_refs_branches_remote__ambiguous_remote_returns_error(void)
 {
 	git_remote *remote;
+	git_buf buf;
 
 	/* Create the remote */
 	cl_git_pass(git_remote_create(&remote, g_repo, "addtest", "http://github.com/libgit2/libgit2"));
@@ -80,7 +67,7 @@ void test_refs_branches_remote__ambiguous_remote_returns_error(void)
 	git_remote_free(remote);
 
 	giterr_clear();
-	cl_git_fail_with(git_branch_remote_name(NULL, 0, g_repo,
-		remote_tracking_branch_name), GIT_EAMBIGUOUS);
+	memset(&buf, 0, sizeof(git_buf));
+	cl_git_fail_with(git_branch_remote_name(&buf, g_repo, remote_tracking_branch_name), GIT_EAMBIGUOUS);
 	cl_assert(giterr_last() != NULL);
 }
diff --git a/tests/refs/branches/upstreamname.c b/tests/refs/branches/upstreamname.c
index f05607d..d30002e 100644
--- a/tests/refs/branches/upstreamname.c
+++ b/tests/refs/branches/upstreamname.c
@@ -21,7 +21,7 @@ void test_refs_branches_upstreamname__cleanup(void)
 
 void test_refs_branches_upstreamname__can_retrieve_the_remote_tracking_reference_name_of_a_local_branch(void)
 {
-	cl_git_pass(git_branch_upstream__name(
+	cl_git_pass(git_branch_upstream_name(
 		&upstream_name, repo, "refs/heads/master"));
 
 	cl_assert_equal_s("refs/remotes/test/master", git_buf_cstr(&upstream_name));
@@ -29,14 +29,8 @@ void test_refs_branches_upstreamname__can_retrieve_the_remote_tracking_reference
 
 void test_refs_branches_upstreamname__can_retrieve_the_local_upstream_reference_name_of_a_local_branch(void)
 {
-	cl_git_pass(git_branch_upstream__name(
+	cl_git_pass(git_branch_upstream_name(
 		&upstream_name, repo, "refs/heads/track-local"));
 
 	cl_assert_equal_s("refs/heads/master", git_buf_cstr(&upstream_name));
 }
-
-void test_refs_branches_upstreamname__can_return_the_size_of_thelocal_upstream_reference_name_of_a_local_branch(void)
-{
-	cl_assert_equal_i((int)strlen("refs/heads/master") + 1,
-		git_branch_upstream_name(NULL, 0, repo, "refs/heads/track-local"));
-}