diff --git a/include/git2/diff.h b/include/git2/diff.h
index 121c9df5c..71a8b72bf 100644
--- a/include/git2/diff.h
+++ b/include/git2/diff.h
@@ -78,7 +78,7 @@ typedef enum {
 	GIT_DIFF_IGNORE_WHITESPACE_CHANGE = (1 << 3),
 	/** Ignore whitespace at end of line */
 	GIT_DIFF_IGNORE_WHITESPACE_EOL = (1 << 4),
-	/** Exclude submodules from the diff completely */
+	/** Treat all submodules as unmodified */
 	GIT_DIFF_IGNORE_SUBMODULES = (1 << 5),
 	/** Use the "patience diff" algorithm (currently unimplemented) */
 	GIT_DIFF_PATIENCE = (1 << 6),
@@ -314,6 +314,8 @@ typedef int (*git_diff_notify_cb)(
  * - `notify_cb` is an optional callback function, notifying the consumer of
  *   which files are being examined as the diff is generated
  * - `notify_payload` is the payload data to pass to the `notify_cb` function
+ * - `ignore_submodules` overrides the submodule ignore setting for all
+ *   submodules in the diff.
  */
 typedef struct {
 	unsigned int version;      /**< version for the struct */
@@ -326,6 +328,7 @@ typedef struct {
 	git_off_t max_size;        /**< defaults to 512MB */
 	git_diff_notify_cb notify_cb;
 	void *notify_payload;
+	git_submodule_ignore_t ignore_submodules; /** << submodule ignore rule */
 } git_diff_options;
 
 #define GIT_DIFF_OPTIONS_VERSION 1
diff --git a/include/git2/submodule.h b/include/git2/submodule.h
index 3267bcd0f..ba7a558d0 100644
--- a/include/git2/submodule.h
+++ b/include/git2/submodule.h
@@ -14,51 +14,18 @@
 /**
  * @file git2/submodule.h
  * @brief Git submodule management utilities
- * @defgroup git_submodule Git submodule management routines
- * @ingroup Git
- * @{
- */
-GIT_BEGIN_DECL
-
-/**
- * Opaque structure representing a submodule.
  *
  * Submodule support in libgit2 builds a list of known submodules and keeps
  * it in the repository.  The list is built from the .gitmodules file, the
  * .git/config file, the index, and the HEAD tree.  Items in the working
  * directory that look like submodules (i.e. a git repo) but are not
  * mentioned in those places won't be tracked.
- */
-typedef struct git_submodule git_submodule;
-
-/**
- * Values that could be specified for the update rule of a submodule.
  *
- * Use the DEFAULT value if you have altered the update value via
- * `git_submodule_set_update()` and wish to reset to the original default.
+ * @defgroup git_submodule Git submodule management routines
+ * @ingroup Git
+ * @{
  */
-typedef enum {
-	GIT_SUBMODULE_UPDATE_DEFAULT = -1,
-	GIT_SUBMODULE_UPDATE_CHECKOUT = 0,
-	GIT_SUBMODULE_UPDATE_REBASE = 1,
-	GIT_SUBMODULE_UPDATE_MERGE = 2,
-	GIT_SUBMODULE_UPDATE_NONE = 3
-} git_submodule_update_t;
-
-/**
- * Values that could be specified for how closely to examine the
- * working directory when getting submodule status.
- *
- * Use the DEFUALT value if you have altered the ignore value via
- * `git_submodule_set_ignore()` and wish to reset to the original value.
- */
-typedef enum {
-	GIT_SUBMODULE_IGNORE_DEFAULT = -1,  /* reset to default */
-	GIT_SUBMODULE_IGNORE_NONE = 0,      /* any change or untracked == dirty */
-	GIT_SUBMODULE_IGNORE_UNTRACKED = 1, /* dirty if tracked files change */
-	GIT_SUBMODULE_IGNORE_DIRTY = 2,     /* only dirty if HEAD moved */
-	GIT_SUBMODULE_IGNORE_ALL = 3        /* never dirty */
-} git_submodule_ignore_t;
+GIT_BEGIN_DECL
 
 /**
  * Return codes for submodule status.
@@ -377,9 +344,9 @@ GIT_EXTERN(git_submodule_ignore_t) git_submodule_ignore(
  * submodule is in memory.  You should call `git_submodule_save()` if you
  * want to persist the new ignore role.
  *
- * Calling this again with GIT_SUBMODULE_IGNORE_DEFAULT or calling
- * `git_submodule_reload()` will revert the rule to the value that was in the
- * original config.
+ * Calling this again with GIT_SUBMODULE_IGNORE_RESET or calling
+ * `git_submodule_reload()` will revert the rule to the value that was in
+ * the original config.
  *
  * @return old value for ignore
  */
@@ -399,9 +366,9 @@ GIT_EXTERN(git_submodule_update_t) git_submodule_update(
  * This sets the update rule in memory for the submodule.  You should call
  * `git_submodule_save()` if you want to persist the new update rule.
  *
- * Calling this again with GIT_SUBMODULE_UPDATE_DEFAULT or calling
- * `git_submodule_reload()` will revert the rule to the value that was in the
- * original config.
+ * Calling this again with GIT_SUBMODULE_UPDATE_RESET or calling
+ * `git_submodule_reload()` will revert the rule to the value that was in
+ * the original config.
  *
  * @return old value for update
  */
diff --git a/include/git2/types.h b/include/git2/types.h
index dc344075c..1da0d3ed2 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -229,6 +229,40 @@ typedef struct git_transfer_progress {
  */
 typedef int (*git_transfer_progress_callback)(const git_transfer_progress *stats, void *payload);
 
+/**
+ * Opaque structure representing a submodule.
+ */
+typedef struct git_submodule git_submodule;
+
+/**
+ * Values that could be specified for the update rule of a submodule.
+ *
+ * Use the RESET value if you have altered the in-memory update value via
+ * `git_submodule_set_update()` and wish to reset to the original default.
+ */
+typedef enum {
+	GIT_SUBMODULE_UPDATE_RESET = -1,
+	GIT_SUBMODULE_UPDATE_CHECKOUT = 1,
+	GIT_SUBMODULE_UPDATE_REBASE = 2,
+	GIT_SUBMODULE_UPDATE_MERGE = 3,
+	GIT_SUBMODULE_UPDATE_NONE = 4
+} git_submodule_update_t;
+
+/**
+ * Values that could be specified for how closely to examine the
+ * working directory when getting submodule status.
+ *
+ * Use the RESET value if you have altered the in-memory ignore value via
+ * `git_submodule_set_ignore()` and wish to reset to the original value.
+ */
+typedef enum {
+	GIT_SUBMODULE_IGNORE_RESET = -1,    /* reset to on-disk value */
+	GIT_SUBMODULE_IGNORE_NONE = 1,      /* any change or untracked == dirty */
+	GIT_SUBMODULE_IGNORE_UNTRACKED = 2, /* dirty if tracked files change */
+	GIT_SUBMODULE_IGNORE_DIRTY = 3,     /* only dirty if HEAD moved */
+	GIT_SUBMODULE_IGNORE_ALL = 4        /* never dirty */
+} git_submodule_ignore_t;
+
 /** @} */
 GIT_END_DECL
 
diff --git a/src/diff.c b/src/diff.c
index 2b018188e..5fa635f05 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -78,10 +78,6 @@ static int diff_delta__from_one(
 		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_UNTRACKED))
 		return 0;
 
-	if (entry->mode == GIT_FILEMODE_COMMIT &&
-		DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES))
-		return 0;
-
 	if (!git_pathspec__match(
 			&diff->pathspec, entry->path,
 			DIFF_FLAG_IS_SET(diff, GIT_DIFF_DISABLE_PATHSPEC_MATCH),
@@ -141,11 +137,6 @@ static int diff_delta__from_two(
 		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_UNMODIFIED))
 		return 0;
 
-	if (old_entry->mode == GIT_FILEMODE_COMMIT &&
-		new_entry->mode == GIT_FILEMODE_COMMIT &&
-		DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES))
-		return 0;
-
 	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_REVERSE)) {
 		uint32_t temp_mode = old_mode;
 		const git_index_entry *temp_entry = old_entry;
@@ -431,8 +422,18 @@ static int diff_list_apply_options(
 	if (!opts) {
 		diff->opts.context_lines = config_int(cfg, "diff.context", 3);
 
-		if (config_bool(cfg, "diff.ignoreSubmodules", 0))
-			diff->opts.flags |= GIT_DIFF_IGNORE_SUBMODULES;
+		/* add other defaults here */
+	}
+
+	/* if ignore_submodules not explicitly set, check diff config */
+	if (diff->opts.ignore_submodules <= 0) {
+		const char *str;
+
+		if (git_config_get_string(&str , cfg, "diff.ignoreSubmodules") < 0)
+			giterr_clear();
+		else if (str != NULL &&
+			git_submodule_parse_ignore(&diff->opts.ignore_submodules, str) < 0)
+			giterr_clear();
 	}
 
 	/* if either prefix is not set, figure out appropriate value */
@@ -596,36 +597,44 @@ static int maybe_modified_submodule(
 	int error = 0;
 	git_submodule *sub;
 	unsigned int sm_status = 0;
+	git_submodule_ignore_t ign = diff->opts.ignore_submodules;
 
 	*status = GIT_DELTA_UNMODIFIED;
 
-	if (!DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES) &&
-		!(error = git_submodule_lookup(
-			  &sub, diff->repo, info->nitem->path)) &&
-		git_submodule_ignore(sub) != GIT_SUBMODULE_IGNORE_ALL &&
-		!(error = git_submodule__status(
-			  &sm_status, NULL, NULL, found_oid, sub,
-			  GIT_SUBMODULE_IGNORE_DEFAULT)))
-	{
-		/* check IS_WD_UNMODIFIED because this case is only used
-		 * when the new side of the diff is the working directory
-		 */
-		if (!GIT_SUBMODULE_STATUS_IS_WD_UNMODIFIED(sm_status))
-			*status = GIT_DELTA_MODIFIED;
+	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES) ||
+		ign == GIT_SUBMODULE_IGNORE_ALL)
+		return 0;
 
-		/* now that we have a HEAD OID, check if HEAD moved */
-		if ((sm_status & GIT_SUBMODULE_STATUS_IN_WD) != 0 &&
-			!git_oid_equal(&info->oitem->oid, found_oid))
-			*status = GIT_DELTA_MODIFIED;
+	if ((error = git_submodule_lookup(
+			&sub, diff->repo, info->nitem->path)) < 0) {
+
+		/* GIT_EEXISTS means dir with .git in it was found - ignore it */
+		if (error == GIT_EEXISTS) {
+			giterr_clear();
+			error = 0;
+		}
+		return error;
 	}
 
-	/* GIT_EEXISTS means a dir with .git in it was found - ignore it */
-	if (error == GIT_EEXISTS) {
-		giterr_clear();
-		error = 0;
-	}
+	if (ign <= 0 && git_submodule_ignore(sub) == GIT_SUBMODULE_IGNORE_ALL)
+		return 0;
 
-	return error;
+	if ((error = git_submodule__status(
+			&sm_status, NULL, NULL, found_oid, sub, ign)) < 0)
+		return error;
+
+	/* check IS_WD_UNMODIFIED because this case is only used
+	 * when the new side of the diff is the working directory
+	 */
+	if (!GIT_SUBMODULE_STATUS_IS_WD_UNMODIFIED(sm_status))
+		*status = GIT_DELTA_MODIFIED;
+
+	/* now that we have a HEAD OID, check if HEAD moved */
+	if ((sm_status & GIT_SUBMODULE_STATUS_IN_WD) != 0 &&
+		!git_oid_equal(&info->oitem->oid, found_oid))
+		*status = GIT_DELTA_MODIFIED;
+
+	return 0;
 }
 
 static int maybe_modified(
diff --git a/src/submodule.c b/src/submodule.c
index 0beedeb42..685906332 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -30,6 +30,8 @@ static git_cvar_map _sm_update_map[] = {
 	{GIT_CVAR_STRING, "rebase", GIT_SUBMODULE_UPDATE_REBASE},
 	{GIT_CVAR_STRING, "merge", GIT_SUBMODULE_UPDATE_MERGE},
 	{GIT_CVAR_STRING, "none", GIT_SUBMODULE_UPDATE_NONE},
+	{GIT_CVAR_FALSE, NULL, GIT_SUBMODULE_UPDATE_NONE},
+	{GIT_CVAR_TRUE, NULL, GIT_SUBMODULE_UPDATE_CHECKOUT},
 };
 
 static git_cvar_map _sm_ignore_map[] = {
@@ -37,6 +39,8 @@ static git_cvar_map _sm_ignore_map[] = {
 	{GIT_CVAR_STRING, "untracked", GIT_SUBMODULE_IGNORE_UNTRACKED},
 	{GIT_CVAR_STRING, "dirty", GIT_SUBMODULE_IGNORE_DIRTY},
 	{GIT_CVAR_STRING, "all", GIT_SUBMODULE_IGNORE_ALL},
+	{GIT_CVAR_FALSE, NULL, GIT_SUBMODULE_IGNORE_NONE},
+	{GIT_CVAR_TRUE, NULL, GIT_SUBMODULE_IGNORE_ALL},
 };
 
 static kh_inline khint_t str_hash_no_trailing_slash(const char *s)
@@ -406,11 +410,30 @@ cleanup:
 	return error;
 }
 
+const char *git_submodule_ignore_to_str(git_submodule_ignore_t ignore)
+{
+	int i;
+	for (i = 0; i < (int)ARRAY_SIZE(_sm_ignore_map); ++i)
+		if (_sm_ignore_map[i].map_value == ignore)
+			return _sm_ignore_map[i].str_match;
+	return NULL;
+}
+
+const char *git_submodule_update_to_str(git_submodule_update_t update)
+{
+	int i;
+	for (i = 0; i < (int)ARRAY_SIZE(_sm_update_map); ++i)
+		if (_sm_update_map[i].map_value == update)
+			return _sm_update_map[i].str_match;
+	return NULL;
+}
+
 int git_submodule_save(git_submodule *submodule)
 {
 	int error = 0;
 	git_config_backend *mods;
 	git_buf key = GIT_BUF_INIT;
+	const char *val;
 
 	assert(submodule);
 
@@ -435,22 +458,14 @@ int git_submodule_save(git_submodule *submodule)
 		goto cleanup;
 
 	if (!(error = submodule_config_key_trunc_puts(&key, "update")) &&
-		submodule->update != GIT_SUBMODULE_UPDATE_DEFAULT)
-	{
-		const char *val = (submodule->update == GIT_SUBMODULE_UPDATE_CHECKOUT) ?
-			NULL : _sm_update_map[submodule->update].str_match;
+		(val = git_submodule_update_to_str(submodule->update)) != NULL)
 		error = git_config_file_set_string(mods, key.ptr, val);
-	}
 	if (error < 0)
 		goto cleanup;
 
 	if (!(error = submodule_config_key_trunc_puts(&key, "ignore")) &&
-		submodule->ignore != GIT_SUBMODULE_IGNORE_DEFAULT)
-	{
-		const char *val = (submodule->ignore == GIT_SUBMODULE_IGNORE_NONE) ?
-			NULL : _sm_ignore_map[submodule->ignore].str_match;
+		(val = git_submodule_ignore_to_str(submodule->ignore)) != NULL)
 		error = git_config_file_set_string(mods, key.ptr, val);
-	}
 	if (error < 0)
 		goto cleanup;
 
@@ -554,7 +569,8 @@ const git_oid *git_submodule_wd_id(git_submodule *submodule)
 git_submodule_ignore_t git_submodule_ignore(git_submodule *submodule)
 {
 	assert(submodule);
-	return submodule->ignore;
+	return (submodule->ignore < GIT_SUBMODULE_IGNORE_NONE) ?
+		GIT_SUBMODULE_IGNORE_NONE : submodule->ignore;
 }
 
 git_submodule_ignore_t git_submodule_set_ignore(
@@ -564,7 +580,7 @@ git_submodule_ignore_t git_submodule_set_ignore(
 
 	assert(submodule);
 
-	if (ignore == GIT_SUBMODULE_IGNORE_DEFAULT)
+	if (ignore == GIT_SUBMODULE_IGNORE_RESET)
 		ignore = submodule->ignore_default;
 
 	old = submodule->ignore;
@@ -575,7 +591,8 @@ git_submodule_ignore_t git_submodule_set_ignore(
 git_submodule_update_t git_submodule_update(git_submodule *submodule)
 {
 	assert(submodule);
-	return submodule->update;
+	return (submodule->update < GIT_SUBMODULE_UPDATE_CHECKOUT) ?
+		GIT_SUBMODULE_UPDATE_CHECKOUT : submodule->update;
 }
 
 git_submodule_update_t git_submodule_set_update(
@@ -585,7 +602,7 @@ git_submodule_update_t git_submodule_set_update(
 
 	assert(submodule);
 
-	if (update == GIT_SUBMODULE_UPDATE_DEFAULT)
+	if (update == GIT_SUBMODULE_UPDATE_RESET)
 		update = submodule->update_default;
 
 	old = submodule->update;
@@ -616,6 +633,7 @@ int git_submodule_set_fetch_recurse_submodules(
 int git_submodule_init(git_submodule *submodule, int overwrite)
 {
 	int error;
+	const char *val;
 
 	/* write "submodule.NAME.url" */
 
@@ -632,14 +650,10 @@ int git_submodule_init(git_submodule *submodule, int overwrite)
 
 	/* write "submodule.NAME.update" if not default */
 
-	if (submodule->update == GIT_SUBMODULE_UPDATE_CHECKOUT)
-		error = submodule_update_config(
-			submodule, "update", NULL, (overwrite != 0), false);
-	else if (submodule->update != GIT_SUBMODULE_UPDATE_DEFAULT)
-		error = submodule_update_config(
-			submodule, "update",
-			_sm_update_map[submodule->update].str_match,
-			(overwrite != 0), false);
+	val = (submodule->update == GIT_SUBMODULE_UPDATE_CHECKOUT) ?
+		NULL : git_submodule_update_to_str(submodule->update);
+	error = submodule_update_config(
+		submodule, "update", val, (overwrite != 0), false);
 
 	return error;
 }
@@ -873,7 +887,7 @@ int git_submodule__status(
 	unsigned int status;
 	git_repository *smrepo = NULL;
 
-	if (ign == GIT_SUBMODULE_IGNORE_DEFAULT)
+	if (ign < GIT_SUBMODULE_IGNORE_NONE)
 		ign = sm->ignore;
 
 	/* only return location info if ignore == all */
@@ -926,8 +940,7 @@ int git_submodule_status(unsigned int *status, git_submodule *sm)
 {
 	assert(status && sm);
 
-	return git_submodule__status(
-		status, NULL, NULL, NULL, sm, GIT_SUBMODULE_IGNORE_DEFAULT);
+	return git_submodule__status(status, NULL, NULL, NULL, sm, 0);
 }
 
 int git_submodule_location(unsigned int *location, git_submodule *sm)
@@ -964,7 +977,10 @@ static git_submodule *submodule_alloc(git_repository *repo, const char *name)
 	}
 
 	GIT_REFCOUNT_INC(sm);
-	sm->repo = repo;
+	sm->ignore = sm->ignore_default = GIT_SUBMODULE_IGNORE_NONE;
+	sm->update = sm->update_default = GIT_SUBMODULE_UPDATE_CHECKOUT;
+	sm->repo   = repo;
+
 	return sm;
 }
 
@@ -1039,6 +1055,34 @@ static int submodule_config_error(const char *property, const char *value)
 	return -1;
 }
 
+int git_submodule_parse_ignore(git_submodule_ignore_t *out, const char *value)
+{
+	int val;
+
+	if (git_config_lookup_map_value(
+			&val, _sm_ignore_map, ARRAY_SIZE(_sm_ignore_map), value) < 0) {
+		*out = GIT_SUBMODULE_IGNORE_NONE;
+		return submodule_config_error("ignore", value);
+	}
+
+	*out = (git_submodule_ignore_t)val;
+	return 0;
+}
+
+int git_submodule_parse_update(git_submodule_update_t *out, const char *value)
+{
+	int val;
+
+	if (git_config_lookup_map_value(
+			&val, _sm_update_map, ARRAY_SIZE(_sm_update_map), value) < 0) {
+		*out = GIT_SUBMODULE_UPDATE_CHECKOUT;
+		return submodule_config_error("update", value);
+	}
+
+	*out = (git_submodule_update_t)val;
+	return 0;
+}
+
 static int submodule_load_from_config(
 	const git_config_entry *entry, void *data)
 {
@@ -1120,22 +1164,18 @@ static int submodule_load_from_config(
 			return -1;
 	}
 	else if (strcasecmp(property, "update") == 0) {
-		int val;
-		if (git_config_lookup_map_value(
-			&val, _sm_update_map, ARRAY_SIZE(_sm_update_map), value) < 0)
-			return submodule_config_error("update", value);
-		sm->update_default = sm->update = (git_submodule_update_t)val;
+		if (git_submodule_parse_update(&sm->update, value) < 0)
+			return -1;
+		sm->update_default = sm->update;
 	}
 	else if (strcasecmp(property, "fetchRecurseSubmodules") == 0) {
 		if (git__parse_bool(&sm->fetch_recurse, value) < 0)
 			return submodule_config_error("fetchRecurseSubmodules", value);
 	}
 	else if (strcasecmp(property, "ignore") == 0) {
-		int val;
-		if (git_config_lookup_map_value(
-			&val, _sm_ignore_map, ARRAY_SIZE(_sm_ignore_map), value) < 0)
-			return submodule_config_error("ignore", value);
-		sm->ignore_default = sm->ignore = (git_submodule_ignore_t)val;
+		if (git_submodule_parse_ignore(&sm->ignore, value) < 0)
+			return -1;
+		sm->ignore_default = sm->ignore;
 	}
 	/* ignore other unknown submodule properties */
 
diff --git a/src/submodule.h b/src/submodule.h
index 8db2fff29..b05937503 100644
--- a/src/submodule.h
+++ b/src/submodule.h
@@ -127,4 +127,12 @@ extern int git_submodule_open_bare(
 /* Release reference to submodule object - not currently for external use */
 extern void git_submodule_free(git_submodule *sm);
 
+extern int git_submodule_parse_ignore(
+	git_submodule_ignore_t *out, const char *value);
+extern int git_submodule_parse_update(
+	git_submodule_update_t *out, const char *value);
+
+extern const char *git_submodule_ignore_to_str(git_submodule_ignore_t);
+extern const char *git_submodule_update_to_str(git_submodule_update_t);
+
 #endif
diff --git a/tests-clar/clar_libgit2.h b/tests-clar/clar_libgit2.h
index 3fcf45a37..5371b2864 100644
--- a/tests-clar/clar_libgit2.h
+++ b/tests-clar/clar_libgit2.h
@@ -29,6 +29,9 @@
 
 void cl_git_report_failure(int, const char *, int, const char *);
 
+#define cl_assert_at_line(expr,file,line) \
+	clar__assert((expr) != 0, file, line, "Expression is not true: " #expr, NULL, 1)
+
 #define cl_assert_equal_sz(sz1,sz2) cl_assert_equal_i((int)sz1, (int)(sz2))
 
 /*
diff --git a/tests-clar/diff/submodules.c b/tests-clar/diff/submodules.c
index 4a40affb2..2e425bb11 100644
--- a/tests-clar/diff/submodules.c
+++ b/tests-clar/diff/submodules.c
@@ -49,7 +49,7 @@ static void check_diff_patches_at_line(
 		cl_git_pass(git_diff_get_patch(&patch, &delta, diff, d));
 
 		if (delta->status == GIT_DELTA_UNMODIFIED) {
-			clar__assert(expected[d] == NULL, file, line, "found UNMODIFIED delta where modified was expected", NULL, 1);
+			cl_assert_at_line(expected[d] == NULL, file, line);
 			continue;
 		}
 
@@ -57,7 +57,7 @@ static void check_diff_patches_at_line(
 			continue;
 		if (expected[d] && !strcmp(expected[d], "<END>")) {
 			cl_git_pass(git_diff_patch_to_str(&patch_text, patch));
-			clar__assert(0, file, line, "expected end of deltas, but found more", patch_text, 1);
+			cl_assert_at_line(!strcmp(expected[d], "<END>"), file, line);
 		}
 
 		cl_git_pass(git_diff_patch_to_str(&patch_text, patch));
@@ -67,7 +67,7 @@ static void check_diff_patches_at_line(
 		git__free(patch_text);
 	}
 
-	clar__assert(expected[d] && !strcmp(expected[d], "<END>"), file, line, "found fewer deltas than expected", expected[d], 1);
+	cl_assert_at_line(expected[d] && !strcmp(expected[d], "<END>"), file, line);
 }
 
 #define check_diff_patches(diff, exp) \
@@ -382,3 +382,62 @@ void test_diff_submodules__invalid_cache(void)
 	git_index_free(smindex);
 	git_repository_free(smrepo);
 }
+
+void test_diff_submodules__diff_ignore_options(void)
+{
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	git_diff_list *diff = NULL;
+	static const char *expected_normal[] = {
+		"<SKIP>", /* .gitmodules */
+		NULL, /* not-submodule */
+		NULL, /* not */
+		"diff --git a/sm_changed_file b/sm_changed_file\nindex 4800958..4800958 160000\n--- a/sm_changed_file\n+++ b/sm_changed_file\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0-dirty\n", /* sm_changed_file */
+		"diff --git a/sm_changed_head b/sm_changed_head\nindex 4800958..3d9386c 160000\n--- a/sm_changed_head\n+++ b/sm_changed_head\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 3d9386c507f6b093471a3e324085657a3c2b4247\n", /* sm_changed_head */
+		"diff --git a/sm_changed_index b/sm_changed_index\nindex 4800958..4800958 160000\n--- a/sm_changed_index\n+++ b/sm_changed_index\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0-dirty\n", /* sm_changed_index */
+		"diff --git a/sm_changed_untracked_file b/sm_changed_untracked_file\nindex 4800958..4800958 160000\n--- a/sm_changed_untracked_file\n+++ b/sm_changed_untracked_file\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0-dirty\n", /* sm_changed_untracked_file */
+		"diff --git a/sm_missing_commits b/sm_missing_commits\nindex 4800958..5e49635 160000\n--- a/sm_missing_commits\n+++ b/sm_missing_commits\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 5e4963595a9774b90524d35a807169049de8ccad\n", /* sm_missing_commits */
+		"<END>"
+	};
+	static const char *expected_ignore_all[] = {
+		"<SKIP>", /* .gitmodules */
+		NULL, /* not-submodule */
+		NULL, /* not */
+		"<END>"
+	};
+	static const char *expected_ignore_dirty[] = {
+		"<SKIP>", /* .gitmodules */
+		NULL, /* not-submodule */
+		NULL, /* not */
+		"diff --git a/sm_changed_head b/sm_changed_head\nindex 4800958..3d9386c 160000\n--- a/sm_changed_head\n+++ b/sm_changed_head\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 3d9386c507f6b093471a3e324085657a3c2b4247\n", /* sm_changed_head */
+		"diff --git a/sm_missing_commits b/sm_missing_commits\nindex 4800958..5e49635 160000\n--- a/sm_missing_commits\n+++ b/sm_missing_commits\n@@ -1 +1 @@\n-Subproject commit 480095882d281ed676fe5b863569520e54a7d5c0\n+Subproject commit 5e4963595a9774b90524d35a807169049de8ccad\n", /* sm_missing_commits */
+		"<END>"
+	};
+
+	setup_submodules2();
+
+	opts.flags = GIT_DIFF_INCLUDE_UNTRACKED;
+	opts.old_prefix = "a"; opts.new_prefix = "b";
+
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, NULL, &opts));
+	check_diff_patches(diff, expected_normal);
+	git_diff_list_free(diff);
+
+	opts.flags |= GIT_DIFF_IGNORE_SUBMODULES;
+
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, NULL, &opts));
+	check_diff_patches(diff, expected_ignore_all);
+	git_diff_list_free(diff);
+
+	opts.flags &= ~GIT_DIFF_IGNORE_SUBMODULES;
+	opts.ignore_submodules = GIT_SUBMODULE_IGNORE_ALL;
+
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, NULL, &opts));
+	check_diff_patches(diff, expected_ignore_all);
+	git_diff_list_free(diff);
+
+	opts.ignore_submodules = GIT_SUBMODULE_IGNORE_DIRTY;
+
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, NULL, &opts));
+	check_diff_patches(diff, expected_ignore_dirty);
+	git_diff_list_free(diff);
+}
diff --git a/tests-clar/submodule/modify.c b/tests-clar/submodule/modify.c
index 94eb3738a..c0498ce6e 100644
--- a/tests-clar/submodule/modify.c
+++ b/tests-clar/submodule/modify.c
@@ -204,10 +204,10 @@ void test_submodule_modify__edit_and_save(void)
 	cl_git_pass(git_submodule_set_url(sm1, old_url));
 	cl_assert_equal_i(
 		(int)GIT_SUBMODULE_IGNORE_UNTRACKED,
-		(int)git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_DEFAULT));
+		(int)git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_RESET));
 	cl_assert_equal_i(
 		(int)GIT_SUBMODULE_UPDATE_REBASE,
-		(int)git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_DEFAULT));
+		(int)git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_RESET));
 	cl_assert_equal_i(
 		1, git_submodule_set_fetch_recurse_submodules(sm1, old_fetchrecurse));
 
@@ -228,10 +228,10 @@ void test_submodule_modify__edit_and_save(void)
 	cl_git_pass(git_submodule_save(sm1));
 
 	/* attempt to "revert" values */
-	git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_DEFAULT);
-	git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_DEFAULT);
+	git_submodule_set_ignore(sm1, GIT_SUBMODULE_IGNORE_RESET);
+	git_submodule_set_update(sm1, GIT_SUBMODULE_UPDATE_RESET);
 
-	/* but ignore and update should NOT revert because the DEFAULT
+	/* but ignore and update should NOT revert because the RESET
 	 * should now be the newly saved value...
 	 */
 	cl_assert_equal_i(