thodg/libgit2

diff --git a/include/git2/rebase.h b/include/git2/rebase.h
index 32b4ff6..e123ae5 100644
--- a/include/git2/rebase.h
+++ b/include/git2/rebase.h
@@ -124,6 +124,18 @@ GIT_EXTERN(int) git_rebase_abort(
 	git_repository *repo,
 	const git_signature *signature);
 
+/**
+ * Finishes a rebase that is currently in progress once all patches have
+ * been applied.
+ *
+ * @param repo The repository with the in-progress rebase
+ * @param signature The identity that is finishing the rebase
+ * @param Zero on success; -1 on error
+ */
+GIT_EXTERN(int) git_rebase_finish(
+	git_repository *repo,
+	const git_signature *signature);
+
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/src/rebase.c b/src/rebase.c
index a28a928..101dfb1 100644
--- a/src/rebase.c
+++ b/src/rebase.c
@@ -64,6 +64,8 @@ typedef struct {
 	char *orig_head_name;
 	git_oid orig_head_id;
 
+	git_oid onto_id;
+
 	union {
 		struct git_rebase_state_merge merge;
 	};
@@ -189,7 +191,7 @@ done:
 static int rebase_state(git_rebase_state *state, git_repository *repo)
 {
 	git_buf path = GIT_BUF_INIT, orig_head_name = GIT_BUF_INIT,
-		orig_head_id = GIT_BUF_INIT;
+		orig_head_id = GIT_BUF_INIT, onto_id = GIT_BUF_INIT;
 	int state_path_len, error;
 
 	memset(state, 0x0, sizeof(git_rebase_state));
@@ -237,6 +239,17 @@ static int rebase_state(git_rebase_state *state, git_repository *repo)
 	if ((error = git_oid_fromstr(&state->orig_head_id, orig_head_id.ptr)) < 0)
 		goto done;
 
+	git_buf_truncate(&path, state_path_len);
+
+	if ((error = git_buf_joinpath(&path, path.ptr, ONTO_FILE)) < 0 ||
+		(error = git_futils_readbuffer(&onto_id, path.ptr)) < 0)
+		goto done;
+
+	git_buf_rtrim(&onto_id);
+
+	if ((error = git_oid_fromstr(&state->onto_id, onto_id.ptr)) < 0)
+		goto done;
+
 	if (!state->head_detached)
 		state->orig_head_name = git_buf_detach(&orig_head_name);
 
@@ -808,3 +821,51 @@ done:
 
 	return error;
 }
+
+int git_rebase_finish(git_repository *repo, const git_signature *signature)
+{
+	git_rebase_state state = GIT_REBASE_STATE_INIT;
+	git_reference *terminal_ref = NULL, *branch_ref = NULL, *head_ref = NULL;
+	git_commit *terminal_commit = NULL;
+	git_buf branch_msg = GIT_BUF_INIT, head_msg = GIT_BUF_INIT;
+	char onto[GIT_OID_HEXSZ];
+	int error;
+
+	assert(repo);
+
+	if ((error = rebase_state(&state, repo)) < 0)
+		goto done;
+
+	git_oid_fmt(onto, &state.onto_id);
+
+	if ((error = git_buf_printf(&branch_msg, "rebase finished: %s onto %.*s",
+			state.orig_head_name, GIT_OID_HEXSZ, onto)) < 0 ||
+		(error = git_buf_printf(&head_msg, "rebase finished: returning to %s",
+			state.orig_head_name)) < 0 ||
+		(error = git_repository_head(&terminal_ref, repo)) < 0 ||
+		(error = git_reference_peel((git_object **)&terminal_commit,
+			terminal_ref, GIT_OBJ_COMMIT)) < 0)
+		goto done;
+
+	if ((error = git_reference_create_matching(&branch_ref,
+			repo, state.orig_head_name, git_commit_id(terminal_commit), 1,
+			&state.orig_head_id, signature, branch_msg.ptr)) < 0 ||
+		(error = git_reference_symbolic_create(&head_ref,
+			repo, GIT_HEAD_FILE, state.orig_head_name, 1,
+			signature, head_msg.ptr)) < 0)
+		goto done;
+			
+	error = rebase_finish(&state);
+
+done:
+	git_buf_free(&head_msg);
+	git_buf_free(&branch_msg);
+	git_commit_free(terminal_commit);
+	git_reference_free(head_ref);
+	git_reference_free(branch_ref);
+	git_reference_free(terminal_ref);
+	rebase_state_free(&state);
+
+	return error;
+}
+
diff --git a/tests/rebase/merge.c b/tests/rebase/merge.c
index 31fa6cc..fa37e89 100644
--- a/tests/rebase/merge.c
+++ b/tests/rebase/merge.c
@@ -295,3 +295,60 @@ void test_rebase_merge__commit_drops_already_applied(void)
 	git_reference_free(upstream_ref);
 }
 
+void test_rebase_merge__finish(void)
+{
+	git_reference *branch_ref, *upstream_ref, *head_ref;
+	git_merge_head *branch_head, *upstream_head;
+	git_checkout_options checkout_opts = GIT_CHECKOUT_OPTIONS_INIT;
+	git_oid commit_id;
+	git_reflog *reflog;
+	const git_reflog_entry *reflog_entry;
+	int error;
+
+	checkout_opts.checkout_strategy = GIT_CHECKOUT_SAFE;
+
+	cl_git_pass(git_reference_lookup(&branch_ref, repo, "refs/heads/gravy"));
+	cl_git_pass(git_reference_lookup(&upstream_ref, repo, "refs/heads/veal"));
+
+	cl_git_pass(git_merge_head_from_ref(&branch_head, repo, branch_ref));
+	cl_git_pass(git_merge_head_from_ref(&upstream_head, repo, upstream_ref));
+
+	cl_git_pass(git_rebase(repo, branch_head, upstream_head, NULL, signature, NULL));
+
+	cl_git_pass(git_rebase_next(repo, &checkout_opts));
+	cl_git_pass(git_rebase_commit(&commit_id, repo, NULL, signature,
+		NULL, NULL));
+
+	cl_git_fail(error = git_rebase_next(repo, &checkout_opts));
+	cl_assert_equal_i(GIT_ITEROVER, error);
+
+	cl_git_pass(git_rebase_finish(repo, signature));
+
+	cl_assert_equal_i(GIT_REPOSITORY_STATE_NONE, git_repository_state(repo));
+
+	cl_git_pass(git_reference_lookup(&head_ref, repo, "HEAD"));
+	cl_assert_equal_i(GIT_REF_SYMBOLIC, git_reference_type(head_ref));
+	cl_assert_equal_s("refs/heads/gravy", git_reference_symbolic_target(head_ref));
+
+	/* Make sure the reflogs are updated appropriately */
+	cl_git_pass(git_reflog_read(&reflog, repo, "HEAD"));
+	cl_assert(reflog_entry = git_reflog_entry_byindex(reflog, 0));
+	cl_assert_equal_oid(&commit_id, git_reflog_entry_id_old(reflog_entry));
+	cl_assert_equal_oid(&commit_id, git_reflog_entry_id_new(reflog_entry));
+	cl_assert_equal_s("rebase finished: returning to refs/heads/gravy", git_reflog_entry_message(reflog_entry));
+	git_reflog_free(reflog);
+
+	cl_git_pass(git_reflog_read(&reflog, repo, "refs/heads/gravy"));
+	cl_assert(reflog_entry = git_reflog_entry_byindex(reflog, 0));
+	cl_assert_equal_oid(git_merge_head_id(branch_head), git_reflog_entry_id_old(reflog_entry));
+	cl_assert_equal_oid(&commit_id, git_reflog_entry_id_new(reflog_entry));
+	cl_assert_equal_s("rebase finished: refs/heads/gravy onto f87d14a4a236582a0278a916340a793714256864", git_reflog_entry_message(reflog_entry));
+
+	git_reflog_free(reflog);
+	git_merge_head_free(branch_head);
+	git_merge_head_free(upstream_head);
+	git_reference_free(head_ref);
+	git_reference_free(branch_ref);
+	git_reference_free(upstream_ref);
+}
+