thodg/libgit2

diff --git a/include/git2/worktree.h b/include/git2/worktree.h
index 4c4f928..bc1e402 100644
--- a/include/git2/worktree.h
+++ b/include/git2/worktree.h
@@ -74,6 +74,25 @@ GIT_EXTERN(void) git_worktree_free(git_worktree *wt);
  */
 GIT_EXTERN(int) git_worktree_validate(const git_worktree *wt);
 
+typedef struct git_worktree_add_options {
+	unsigned int version;
+} git_worktree_add_options;
+
+#define GIT_WORKTREE_ADD_OPTIONS_VERSION 1
+#define GIT_WORKTREE_ADD_OPTIONS_INIT {GIT_WORKTREE_ADD_OPTIONS_VERSION}
+
+/**
+ * Initializes a `git_worktree_add_options` with default vaules.
+ * Equivalent to creating an instance with
+ * GIT_WORKTREE_ADD_OPTIONS_INIT.
+ *
+ * @param opts the struct to initialize
+ * @param version Verison of struct; pass `GIT_WORKTREE_ADD_OPTIONS_VERSION`
+ * @return Zero on success; -1 on failure.
+ */
+int git_worktree_add_init_options(git_worktree_add_options *opts,
+	unsigned int version);
+
 /**
  * Add a new working tree
  *
@@ -85,9 +104,12 @@ GIT_EXTERN(int) git_worktree_validate(const git_worktree *wt);
  * @param repo Repository to create working tree for
  * @param name Name of the working tree
  * @param path Path to create working tree at
+ * @param opts Options to modify default behavior. May be NULL
  * @return 0 or an error code
  */
-GIT_EXTERN(int) git_worktree_add(git_worktree **out, git_repository *repo, const char *name, const char *path);
+GIT_EXTERN(int) git_worktree_add(git_worktree **out, git_repository *repo,
+	const char *name, const char *path,
+	const git_worktree_add_options *opts);
 
 /**
  * Lock worktree if not already locked
diff --git a/src/worktree.c b/src/worktree.c
index 55fbf52..6e797f3 100644
--- a/src/worktree.c
+++ b/src/worktree.c
@@ -269,15 +269,32 @@ out:
 	return err;
 }
 
-int git_worktree_add(git_worktree **out, git_repository *repo, const char *name, const char *worktree)
+int git_worktree_add_init_options(git_worktree_add_options *opts,
+	unsigned int version)
+{
+	GIT_INIT_STRUCTURE_FROM_TEMPLATE(opts, version,
+		git_worktree_add_options, GIT_WORKTREE_ADD_OPTIONS_INIT);
+	return 0;
+}
+
+int git_worktree_add(git_worktree **out, git_repository *repo,
+	const char *name, const char *worktree,
+	const git_worktree_add_options *opts)
 {
 	git_buf gitdir = GIT_BUF_INIT, wddir = GIT_BUF_INIT, buf = GIT_BUF_INIT;
 	git_reference *ref = NULL, *head = NULL;
 	git_commit *commit = NULL;
 	git_repository *wt = NULL;
 	git_checkout_options coopts = GIT_CHECKOUT_OPTIONS_INIT;
+	git_worktree_add_options wtopts = GIT_WORKTREE_ADD_OPTIONS_INIT;
 	int err;
 
+	GITERR_CHECK_VERSION(
+		opts, GIT_WORKTREE_ADD_OPTIONS_VERSION, "git_worktree_add_options");
+
+	if (opts)
+		memcpy(&wtopts, opts, sizeof(wtopts));
+
 	assert(out && repo && name && worktree);
 
 	*out = NULL;
diff --git a/tests/worktree/submodule.c b/tests/worktree/submodule.c
index 5620775..2943852 100644
--- a/tests/worktree/submodule.c
+++ b/tests/worktree/submodule.c
@@ -74,7 +74,7 @@ void test_worktree_submodule__resolve_relative_url(void)
 	cl_git_pass(git_repository_open(&child.repo, WORKTREE_CHILD));
 
 	/* Create worktree of submodule repository */
-	cl_git_pass(git_worktree_add(&wt, child.repo, "subdir", wt_path.ptr));
+	cl_git_pass(git_worktree_add(&wt, child.repo, "subdir", wt_path.ptr, NULL));
 	cl_git_pass(git_repository_open_from_worktree(&repo, wt));
 
 	cl_git_pass(git_submodule_resolve_url(&sm_relative_path, repo,
diff --git a/tests/worktree/worktree.c b/tests/worktree/worktree.c
index 73991bf..f908958 100644
--- a/tests/worktree/worktree.c
+++ b/tests/worktree/worktree.c
@@ -215,7 +215,7 @@ void test_worktree_worktree__init(void)
 	git_buf path = GIT_BUF_INIT;
 
 	cl_git_pass(git_buf_joinpath(&path, fixture.repo->workdir, "../worktree-new"));
-	cl_git_pass(git_worktree_add(&wt, fixture.repo, "worktree-new", path.ptr));
+	cl_git_pass(git_worktree_add(&wt, fixture.repo, "worktree-new", path.ptr, NULL));
 
 	/* Open and verify created repo */
 	cl_git_pass(git_repository_open(&repo, path.ptr));
@@ -240,7 +240,7 @@ void test_worktree_worktree__init_existing_branch(void)
 	cl_git_pass(git_branch_create(&branch, fixture.repo, "worktree-new", commit, false));
 
 	cl_git_pass(git_buf_joinpath(&path, fixture.repo->workdir, "../worktree-new"));
-	cl_git_fail(git_worktree_add(&wt, fixture.repo, "worktree-new", path.ptr));
+	cl_git_fail(git_worktree_add(&wt, fixture.repo, "worktree-new", path.ptr, NULL));
 
 	git_buf_free(&path);
 	git_commit_free(commit);
@@ -254,7 +254,7 @@ void test_worktree_worktree__init_existing_worktree(void)
 	git_buf path = GIT_BUF_INIT;
 
 	cl_git_pass(git_buf_joinpath(&path, fixture.repo->workdir, "../worktree-new"));
-	cl_git_fail(git_worktree_add(&wt, fixture.repo, "testrepo-worktree", path.ptr));
+	cl_git_fail(git_worktree_add(&wt, fixture.repo, "testrepo-worktree", path.ptr, NULL));
 
 	cl_git_pass(git_worktree_lookup(&wt, fixture.repo, "testrepo-worktree"));
 	cl_assert_equal_s(wt->gitlink_path, fixture.worktree->gitlink);
@@ -279,7 +279,7 @@ void test_worktree_worktree__init_existing_path(void)
 	}
 
 	cl_git_pass(git_buf_joinpath(&path, fixture.repo->workdir, "../testrepo-worktree"));
-	cl_git_fail(git_worktree_add(&wt, fixture.repo, "worktree-new", path.ptr));
+	cl_git_fail(git_worktree_add(&wt, fixture.repo, "worktree-new", path.ptr, NULL));
 
 	/* Verify files have not been re-created */
 	for (i = 0; i < ARRAY_SIZE(wtfiles); i++) {
@@ -303,7 +303,7 @@ void test_worktree_worktree__init_submodule(void)
 	cl_git_pass(git_buf_joinpath(&path, repo->workdir, "sm_unchanged"));
 	cl_git_pass(git_repository_open(&sm, path.ptr));
 	cl_git_pass(git_buf_joinpath(&path, repo->workdir, "../worktree/"));
-	cl_git_pass(git_worktree_add(&worktree, sm, "repo-worktree", path.ptr));
+	cl_git_pass(git_worktree_add(&worktree, sm, "repo-worktree", path.ptr, NULL));
 	cl_git_pass(git_repository_open_from_worktree(&wt, worktree));
 
 	cl_git_pass(git_path_prettify_dir(&path, path.ptr, NULL));