thodg/libgit2

diff --git a/examples/diff.c b/examples/diff.c
index a465182..b81a868 100644
--- a/examples/diff.c
+++ b/examples/diff.c
@@ -133,7 +133,7 @@ int main(int argc, char *argv[])
 {
 	git_repository *repo = NULL;
 	git_tree *t1 = NULL, *t2 = NULL;
-	git_diff_options opts;
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff;
 	int i, color = -1, compact = 0, cached = 0;
 	char *a, *dir = ".", *treeish1 = NULL, *treeish2 = NULL;
diff --git a/include/git2/diff.h b/include/git2/diff.h
index 855e4be..16a24b5 100644
--- a/include/git2/diff.h
+++ b/include/git2/diff.h
@@ -117,7 +117,7 @@ typedef struct {
 } git_diff_options;
 
 #define GIT_DIFF_OPTIONS_VERSION 1
-#define GIT_DIFF_OPTIONS_INIT = {GIT_DIFF_OPTIONS_VERSION, 0}
+#define GIT_DIFF_OPTIONS_INIT {GIT_DIFF_OPTIONS_VERSION, 0}
 
 /**
  * The diff list object that contains all individual file deltas.
diff --git a/src/checkout.c b/src/checkout.c
index 2a7ad70..06407bb 100644
--- a/src/checkout.c
+++ b/src/checkout.c
@@ -622,7 +622,7 @@ int git_checkout_index(
 	git_checkout_opts *opts)
 {
 	git_diff_list *diff = NULL;
-	git_diff_options diff_opts = {0};
+	git_diff_options diff_opts = GIT_DIFF_OPTIONS_INIT;
 	git_checkout_opts checkout_opts;
 	checkout_diff_data data;
 	git_buf workdir = GIT_BUF_INIT;
diff --git a/src/diff.c b/src/diff.c
index 86f76f9..722acbe 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -755,14 +755,15 @@ fail:
 	return error;
 }
 
-
 #define DIFF_FROM_ITERATORS(MAKE_FIRST, MAKE_SECOND) do { \
 	git_iterator *a = NULL, *b = NULL; \
 	char *pfx = opts ? git_pathspec_prefix(&opts->pathspec) : NULL; \
-    if (!(error = MAKE_FIRST) && !(error = MAKE_SECOND)) \
+	if (!git_diff__opts_has_valid_version(opts)) \
+		error = -1; \
+	else if (!(error = MAKE_FIRST) && !(error = MAKE_SECOND)) \
 		error = diff_from_iterators(diff, repo, a, b, opts); \
 	git__free(pfx); git_iterator_free(a); git_iterator_free(b); \
-    } while (0)
+} while (0)
 
 int git_diff_tree_to_tree(
 	git_diff_list **diff,
diff --git a/src/diff.h b/src/diff.h
index 1e3be75..1f45af1 100644
--- a/src/diff.h
+++ b/src/diff.h
@@ -61,5 +61,19 @@ extern bool git_diff_delta__should_skip(
 extern int git_diff__oid_for_file(
 	git_repository *, const char *, uint16_t, git_off_t, git_oid *);
 
+
+GIT_INLINE(bool) git_diff__opts_has_valid_version(const git_diff_options *opts)
+{
+	if (!opts)
+		return true;
+
+	if (opts->version > 0 && opts->version <= GIT_DIFF_OPTIONS_VERSION)
+		return true;
+
+	giterr_set(GITERR_INVALID, "Invalid version %d in git_diff_options", opts->version);
+	return false;
+}
+
+
 #endif
 
diff --git a/src/diff_output.c b/src/diff_output.c
index e137fd0..6316bfa 100644
--- a/src/diff_output.c
+++ b/src/diff_output.c
@@ -1266,6 +1266,9 @@ int git_diff_blobs(
 	git_diff_delta delta;
 	git_diff_patch patch;
 
+   if (!git_diff__opts_has_valid_version(options))
+		return -1;
+
 	if (options && (options->flags & GIT_DIFF_REVERSE)) {
 		git_blob *swap = old_blob;
 		old_blob = new_blob;
diff --git a/src/stash.c b/src/stash.c
index edd8c55..261d3b1 100644
--- a/src/stash.c
+++ b/src/stash.c
@@ -229,7 +229,7 @@ static int build_untracked_tree(
 {
 	git_tree *i_tree = NULL;
 	git_diff_list *diff = NULL;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	struct cb_data data = {0};
 	int error = -1;
 
@@ -315,7 +315,7 @@ static int build_workdir_tree(
 	git_repository *repo = git_index_owner(index);
 	git_tree *b_tree = NULL;
 	git_diff_list *diff = NULL, *diff2 = NULL;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	struct cb_data data = {0};
 	int error = -1;
 
diff --git a/src/status.c b/src/status.c
index c7dea2c..ca500c5 100644
--- a/src/status.c
+++ b/src/status.c
@@ -108,7 +108,7 @@ int git_status_foreach_ext(
 	void *payload)
 {
 	int err = 0;
-	git_diff_options diffopt;
+	git_diff_options diffopt = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *idx2head = NULL, *wd2idx = NULL;
 	git_tree *head = NULL;
 	git_status_show_t show =
@@ -126,7 +126,6 @@ int git_status_foreach_ext(
 		!(err == GIT_ENOTFOUND || err == GIT_EORPHANEDHEAD))
 			return err;
 
-	memset(&diffopt, 0, sizeof(diffopt));
 	memcpy(&diffopt.pathspec, &opts->pathspec, sizeof(diffopt.pathspec));
 
 	diffopt.flags = GIT_DIFF_INCLUDE_TYPECHANGE;
diff --git a/src/submodule.c b/src/submodule.c
index c117255..7ac666c 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -1439,7 +1439,7 @@ static int submodule_wd_status(unsigned int *status, git_submodule *sm)
 
 	if (sm_repo != NULL) {
 		git_tree *sm_head;
-		git_diff_options opt;
+		git_diff_options opt = GIT_DIFF_OPTIONS_INIT;
 		git_diff_list *diff;
 
 		/* the diffs below could be optimized with an early termination
@@ -1452,7 +1452,6 @@ static int submodule_wd_status(unsigned int *status, git_submodule *sm)
 		if ((error = git_repository_head_tree(&sm_head, sm_repo)) < 0)
 			return error;
 
-		memset(&opt, 0, sizeof(opt));
 		if (sm->ignore == GIT_SUBMODULE_IGNORE_NONE)
 			opt.flags |= GIT_DIFF_INCLUDE_UNTRACKED;
 
diff --git a/tests-clar/diff/blob.c b/tests-clar/diff/blob.c
index 6a5645d..ae3129c 100644
--- a/tests-clar/diff/blob.c
+++ b/tests-clar/diff/blob.c
@@ -12,7 +12,7 @@ void test_diff_blob__initialize(void)
 
 	g_repo = cl_git_sandbox_init("attr");
 
-	memset(&opts, 0, sizeof(opts));
+	reset_diff_opts(&opts);
 	opts.context_lines = 1;
 	opts.interhunk_lines = 0;
 
@@ -313,3 +313,25 @@ void test_diff_blob__comparing_two_text_blobs_honors_interhunkcontext(void)
 
 	git_blob_free(old_d);
 }
+
+void test_diff_blob__checks_options_version_too_low(void)
+{
+	const git_error *err;
+
+	opts.version = 0;
+	cl_git_fail(git_diff_blobs(
+		d, alien, &opts, diff_file_cb, diff_hunk_cb, diff_line_cb, &expected));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+}
+
+void test_diff_blob__checks_options_version_too_high(void)
+{
+	const git_error *err;
+
+	opts.version = 1024;
+	cl_git_fail(git_diff_blobs(
+		d, alien, &opts, diff_file_cb, diff_hunk_cb, diff_line_cb, &expected));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+}
diff --git a/tests-clar/diff/diff_helpers.h b/tests-clar/diff/diff_helpers.h
index 12591f6..0f7c0e4 100644
--- a/tests-clar/diff/diff_helpers.h
+++ b/tests-clar/diff/diff_helpers.h
@@ -48,3 +48,10 @@ extern int diff_foreach_via_iterator(
 	void *data);
 
 extern void diff_print(FILE *fp, git_diff_list *diff);
+
+
+GIT_INLINE(void) reset_diff_opts(git_diff_options *opts)
+{
+	git_diff_options init = GIT_DIFF_OPTIONS_INIT;
+	memmove(opts, &init, sizeof(init));
+}
diff --git a/tests-clar/diff/diffiter.c b/tests-clar/diff/diffiter.c
index 133392c..306a13e 100644
--- a/tests-clar/diff/diffiter.c
+++ b/tests-clar/diff/diffiter.c
@@ -76,7 +76,7 @@ void test_diff_diffiter__iterate_files_2(void)
 void test_diff_diffiter__iterate_files_and_hunks(void)
 {
 	git_repository *repo = cl_git_sandbox_init("status");
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	size_t d, num_d;
 	int file_count = 0, hunk_count = 0;
@@ -129,7 +129,7 @@ void test_diff_diffiter__iterate_files_and_hunks(void)
 void test_diff_diffiter__max_size_threshold(void)
 {
 	git_repository *repo = cl_git_sandbox_init("status");
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	int file_count = 0, binary_count = 0, hunk_count = 0;
 	size_t d, num_d;
@@ -207,7 +207,7 @@ void test_diff_diffiter__max_size_threshold(void)
 void test_diff_diffiter__iterate_all(void)
 {
 	git_repository *repo = cl_git_sandbox_init("status");
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp = {0};
 	size_t d, num_d;
@@ -280,7 +280,7 @@ static void iterate_over_patch(git_diff_patch *patch, diff_expects *exp)
 void test_diff_diffiter__iterate_randomly_while_saving_state(void)
 {
 	git_repository *repo = cl_git_sandbox_init("status");
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp = {0};
 	git_diff_patch *patches[PATCH_CACHE];
@@ -441,3 +441,25 @@ void test_diff_diffiter__iterate_and_generate_patch_text(void)
 
 	git_diff_list_free(diff);
 }
+
+void test_diff_diffiter__checks_options_version(void)
+{
+	git_repository *repo = cl_git_sandbox_init("status");
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	git_diff_list *diff = NULL;
+	const git_error *err;
+
+	opts.version = 0;
+	opts.flags |= GIT_DIFF_INCLUDE_IGNORED | GIT_DIFF_INCLUDE_UNTRACKED;
+
+	cl_git_fail(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+
+	giterr_clear();
+	opts.version = 1024;
+	cl_git_fail(git_diff_workdir_to_index(&diff, repo, NULL, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+}
+
diff --git a/tests-clar/diff/index.c b/tests-clar/diff/index.c
index 9591e34..267b329 100644
--- a/tests-clar/diff/index.c
+++ b/tests-clar/diff/index.c
@@ -20,7 +20,7 @@ void test_diff_index__0(void)
 	const char *b_commit = "0017bd4ab1ec3"; /* the start */
 	git_tree *a = resolve_commit_oid_to_tree(g_repo, a_commit);
 	git_tree *b = resolve_commit_oid_to_tree(g_repo, b_commit);
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 
@@ -113,7 +113,7 @@ void test_diff_index__1(void)
 	const char *b_commit = "0017bd4ab1ec3"; /* the start */
 	git_tree *a = resolve_commit_oid_to_tree(g_repo, a_commit);
 	git_tree *b = resolve_commit_oid_to_tree(g_repo, b_commit);
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 
@@ -140,3 +140,24 @@ void test_diff_index__1(void)
 	git_tree_free(a);
 	git_tree_free(b);
 }
+
+void test_diff_index__checks_options_version(void)
+{
+	const char *a_commit = "26a125ee1bf";
+	git_tree *a = resolve_commit_oid_to_tree(g_repo, a_commit);
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	git_diff_list *diff;
+	const git_error *err;
+
+	opts.version = 0;
+	cl_git_fail(git_diff_index_to_tree(&diff, g_repo, a, NULL, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+
+	giterr_clear();
+	opts.version = 1024;
+	cl_git_fail(git_diff_index_to_tree(&diff, g_repo, a, NULL, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+}
+
diff --git a/tests-clar/diff/rename.c b/tests-clar/diff/rename.c
index 0d57f8f..18b7f77 100644
--- a/tests-clar/diff/rename.c
+++ b/tests-clar/diff/rename.c
@@ -33,7 +33,7 @@ void test_diff_rename__match_oid(void)
 	const char *new_sha = "2bc7f351d20b53f1c72c16c4b036e491c478c49a";
 	git_tree *old_tree, *new_tree;
 	git_diff_list *diff;
-	git_diff_options diffopts = {0};
+	git_diff_options diffopts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_find_options opts;
 	diff_expects exp;
 
@@ -43,7 +43,6 @@ void test_diff_rename__match_oid(void)
 	/* Must pass GIT_DIFF_INCLUDE_UNMODIFIED if you expect to emulate
 	 * --find-copies-harder during rename transformion...
 	 */
-	memset(&diffopts, 0, sizeof(diffopts));
 	diffopts.flags |= GIT_DIFF_INCLUDE_UNMODIFIED;
 
 	cl_git_pass(git_diff_tree_to_tree(
diff --git a/tests-clar/diff/tree.c b/tests-clar/diff/tree.c
index 58dc4e6..442e53b 100644
--- a/tests-clar/diff/tree.c
+++ b/tests-clar/diff/tree.c
@@ -19,7 +19,7 @@ void test_diff_tree__0(void)
 	const char *b_commit = "370fe9ec22";
 	const char *c_commit = "f5b0af1fb4f5c";
 	git_tree *a, *b, *c;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 
@@ -175,7 +175,7 @@ void test_diff_tree__bare(void)
 	const char *a_commit = "8496071c1b46c85";
 	const char *b_commit = "be3563ae3f79";
 	git_tree *a, *b;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 
@@ -264,7 +264,7 @@ void test_diff_tree__larger_hunks(void)
 	const char *a_commit = "d70d245ed97ed2aa596dd1af6536e4bfdb047b69";
 	const char *b_commit = "7a9e0b02e63179929fed24f0a3e0f19168114d10";
 	git_tree *a, *b;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	size_t d, num_d, h, num_h, l, num_l, header_len, line_len;
 	const git_diff_delta *delta;
@@ -319,3 +319,31 @@ void test_diff_tree__larger_hunks(void)
 	git_tree_free(a);
 	git_tree_free(b);
 }
+
+void test_diff_tree__checks_options_version(void)
+{
+	const char *a_commit = "8496071c1b46c85";
+	const char *b_commit = "be3563ae3f79";
+	git_tree *a, *b;
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	git_diff_list *diff = NULL;
+	const git_error *err;
+
+	g_repo = cl_git_sandbox_init("testrepo.git");
+
+	cl_assert((a = resolve_commit_oid_to_tree(g_repo, a_commit)) != NULL);
+	cl_assert((b = resolve_commit_oid_to_tree(g_repo, b_commit)) != NULL);
+
+	opts.version = 0;
+	cl_git_fail(git_diff_tree_to_tree(&diff, g_repo, a, b, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+
+	giterr_clear();
+	opts.version = 1024;
+	cl_git_fail(git_diff_tree_to_tree(&diff, g_repo, a, b, &opts));
+	err = giterr_last();
+
+	git_tree_free(a);
+	git_tree_free(b);
+}
diff --git a/tests-clar/diff/workdir.c b/tests-clar/diff/workdir.c
index 57c88c3..10d58b1 100644
--- a/tests-clar/diff/workdir.c
+++ b/tests-clar/diff/workdir.c
@@ -15,7 +15,7 @@ void test_diff_workdir__cleanup(void)
 
 void test_diff_workdir__to_index(void)
 {
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 	int use_iterator;
@@ -69,7 +69,7 @@ void test_diff_workdir__to_tree(void)
 	const char *a_commit = "26a125ee1bf"; /* the current HEAD */
 	const char *b_commit = "0017bd4ab1ec3"; /* the start */
 	git_tree *a, *b;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	git_diff_list *diff2 = NULL;
 	diff_expects exp;
@@ -202,7 +202,7 @@ void test_diff_workdir__to_tree(void)
 
 void test_diff_workdir__to_index_with_pathspec(void)
 {
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 	char *pathspec = NULL;
@@ -420,7 +420,7 @@ void test_diff_workdir__filemode_changes_with_filemode_false(void)
 
 void test_diff_workdir__head_index_and_workdir_all_differ(void)
 {
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff_i2t = NULL, *diff_w2i = NULL;
 	diff_expects exp;
 	char *pathspec = "staged_changes_modified_file";
@@ -518,7 +518,7 @@ void test_diff_workdir__head_index_and_workdir_all_differ(void)
 
 void test_diff_workdir__eof_newline_changes(void)
 {
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 	char *pathspec = "current_file";
@@ -678,7 +678,7 @@ void test_diff_workdir__larger_hunks(void)
 	const char *a_commit = "d70d245ed97ed2aa596dd1af6536e4bfdb047b69";
 	const char *b_commit = "7a9e0b02e63179929fed24f0a3e0f19168114d10";
 	git_tree *a, *b;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	size_t i, d, num_d, h, num_h, l, num_l, header_len, line_len;
 
 	g_repo = cl_git_sandbox_init("diff");
@@ -763,7 +763,7 @@ void test_diff_workdir__submodules(void)
 {
 	const char *a_commit = "873585b94bdeabccea991ea5e3ec1a277895b698";
 	git_tree *a;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	diff_expects exp;
 
@@ -822,7 +822,7 @@ void test_diff_workdir__submodules(void)
 
 void test_diff_workdir__cannot_diff_against_a_bare_repository(void)
 {
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 	git_diff_list *diff = NULL;
 	git_tree *tree;
 
@@ -843,7 +843,7 @@ void test_diff_workdir__to_null_tree(void)
 {
 	git_diff_list *diff;
 	diff_expects exp;
-	git_diff_options opts = {0};
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
 
 	opts.flags = GIT_DIFF_INCLUDE_UNTRACKED |
 		GIT_DIFF_RECURSE_UNTRACKED_DIRS;
@@ -861,3 +861,23 @@ void test_diff_workdir__to_null_tree(void)
 
 	git_diff_list_free(diff);
 }
+
+void test_diff_workdir__checks_options_version(void)
+{
+	git_diff_list *diff;
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	const git_error *err;
+
+	g_repo = cl_git_sandbox_init("status");
+
+	opts.version = 0;
+	cl_git_fail(git_diff_workdir_to_tree(&diff, g_repo, NULL, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+
+	giterr_clear();
+	opts.version = 1024;
+	cl_git_fail(git_diff_workdir_to_tree(&diff, g_repo, NULL, &opts));
+	err = giterr_last();
+	cl_assert_equal_i(GITERR_INVALID, err->klass);
+}