diff --git a/builtin/fsck.c b/builtin/fsck.c
index 821e779..70ff958 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -71,11 +71,6 @@ static const char *printable_type(const struct object_id *oid,
 	return ret;
 }
 
-static int fsck_config(const char *var, const char *value, void *cb)
-{
-	return fsck_config_internal(var, value, cb, &fsck_obj_options);
-}
-
 static int objerror(struct object *obj, const char *err)
 {
 	errors_found |= ERROR_OBJECT;
@@ -89,7 +84,9 @@ static int objerror(struct object *obj, const char *err)
 static int fsck_error_func(struct fsck_options *o,
 			   const struct object_id *oid,
 			   enum object_type object_type,
-			   int msg_type, const char *message)
+			   enum fsck_msg_type msg_type,
+			   enum fsck_msg_id msg_id,
+			   const char *message)
 {
 	switch (msg_type) {
 	case FSCK_WARN:
@@ -197,7 +194,8 @@ static int traverse_reachable(void)
 	return !!result;
 }
 
-static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
+static int mark_used(struct object *obj, enum object_type object_type,
+		     void *data, struct fsck_options *options)
 {
 	if (!obj)
 		return 1;
@@ -803,7 +801,7 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
 	if (name_objects)
 		fsck_enable_object_names(&fsck_walk_options);
 
-	git_config(fsck_config, NULL);
+	git_config(git_fsck_config, &fsck_obj_options);
 
 	if (connectivity_only) {
 		for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
diff --git a/builtin/index-pack.c b/builtin/index-pack.c
index 2189968..15507b5 100644
--- a/builtin/index-pack.c
+++ b/builtin/index-pack.c
@@ -120,7 +120,7 @@ static int nr_threads;
 static int from_stdin;
 static int strict;
 static int do_fsck_object;
-static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
+static struct fsck_options fsck_options = FSCK_OPTIONS_MISSING_GITMODULES;
 static int verbose;
 static int show_resolving_progress;
 static int show_stat;
@@ -212,7 +212,8 @@ static void cleanup_thread(void)
 	free(thread_data);
 }
 
-static int mark_link(struct object *obj, int type, void *data, struct fsck_options *options)
+static int mark_link(struct object *obj, enum object_type type,
+		     void *data, struct fsck_options *options)
 {
 	if (!obj)
 		return -1;
@@ -1712,22 +1713,6 @@ static void show_pack_info(int stat_only)
 	}
 }
 
-static int print_dangling_gitmodules(struct fsck_options *o,
-				     const struct object_id *oid,
-				     enum object_type object_type,
-				     int msg_type, const char *message)
-{
-	/*
-	 * NEEDSWORK: Plumb the MSG_ID (from fsck.c) here and use it
-	 * instead of relying on this string check.
-	 */
-	if (starts_with(message, "gitmodulesMissing")) {
-		printf("%s\n", oid_to_hex(oid));
-		return 0;
-	}
-	return fsck_error_function(o, oid, object_type, msg_type, message);
-}
-
 int cmd_index_pack(int argc, const char **argv, const char *prefix)
 {
 	int i, fix_thin_pack = 0, verify = 0, stat_only = 0, rev_index;
@@ -1948,13 +1933,8 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 	else
 		close(input_fd);
 
-	if (do_fsck_object) {
-		struct fsck_options fo = fsck_options;
-
-		fo.error_func = print_dangling_gitmodules;
-		if (fsck_finish(&fo))
-			die(_("fsck error in pack objects"));
-	}
+	if (do_fsck_object && fsck_finish(&fsck_options))
+		die(_("fsck error in pack objects"));
 
 	free(objects);
 	strbuf_release(&index_name_buf);
diff --git a/builtin/mktag.c b/builtin/mktag.c
index 41a399a..dddcccd 100644
--- a/builtin/mktag.c
+++ b/builtin/mktag.c
@@ -14,15 +14,12 @@ static int option_strict = 1;
 
 static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
 
-static int mktag_config(const char *var, const char *value, void *cb)
-{
-	return fsck_config_internal(var, value, cb, &fsck_options);
-}
-
 static int mktag_fsck_error_func(struct fsck_options *o,
 				 const struct object_id *oid,
 				 enum object_type object_type,
-				 int msg_type, const char *message)
+				 enum fsck_msg_type msg_type,
+				 enum fsck_msg_id msg_id,
+				 const char *message)
 {
 	switch (msg_type) {
 	case FSCK_WARN:
@@ -91,9 +88,10 @@ int cmd_mktag(int argc, const char **argv, const char *prefix)
 		die_errno(_("could not read from stdin"));
 
 	fsck_options.error_func = mktag_fsck_error_func;
-	fsck_set_msg_type(&fsck_options, "extraheaderentry", "warn");
+	fsck_set_msg_type_from_ids(&fsck_options, FSCK_MSG_EXTRA_HEADER_ENTRY,
+				   FSCK_WARN);
 	/* config might set fsck.extraHeaderEntry=* again */
-	git_config(mktag_config, NULL);
+	git_config(git_fsck_config, &fsck_options);
 	if (fsck_tag_standalone(NULL, buf.buf, buf.len, &fsck_options,
 				&tagged_oid, &tagged_type))
 		die(_("tag on stdin did not pass our strict fsck check"));
diff --git a/builtin/unpack-objects.c b/builtin/unpack-objects.c
index a4ba2eb..4a70b17 100644
--- a/builtin/unpack-objects.c
+++ b/builtin/unpack-objects.c
@@ -187,7 +187,8 @@ static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
  * that have reachability requirements and calls this function.
  * Verify its reachability and validity recursively and write it out.
  */
-static int check_object(struct object *obj, int type, void *data, struct fsck_options *options)
+static int check_object(struct object *obj, enum object_type type,
+			void *data, struct fsck_options *options)
 {
 	struct obj_buffer *obj_buf;
 
diff --git a/fetch-pack.c b/fetch-pack.c
index fb04a76..c80eaee 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -38,6 +38,7 @@ static int server_supports_filtering;
 static int advertise_sid;
 static struct shallow_lock shallow_lock;
 static const char *alternate_shallow_file;
+static struct fsck_options fsck_options = FSCK_OPTIONS_MISSING_GITMODULES;
 static struct strbuf fsck_msg_types = STRBUF_INIT;
 static struct string_list uri_protocols = STRING_LIST_INIT_DUP;
 
@@ -987,22 +988,6 @@ static int cmp_ref_by_name(const void *a_, const void *b_)
 	return strcmp(a->name, b->name);
 }
 
-static void fsck_gitmodules_oids(struct oidset *gitmodules_oids)
-{
-	struct oidset_iter iter;
-	const struct object_id *oid;
-	struct fsck_options fo = FSCK_OPTIONS_STRICT;
-
-	if (!oidset_size(gitmodules_oids))
-		return;
-
-	oidset_iter_init(gitmodules_oids, &iter);
-	while ((oid = oidset_iter_next(&iter)))
-		register_found_gitmodules(oid);
-	if (fsck_finish(&fo))
-		die("fsck failed");
-}
-
 static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 				 int fd[2],
 				 const struct ref *orig_ref,
@@ -1017,7 +1002,6 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 	int agent_len;
 	struct fetch_negotiator negotiator_alloc;
 	struct fetch_negotiator *negotiator;
-	struct oidset gitmodules_oids = OIDSET_INIT;
 
 	negotiator = &negotiator_alloc;
 	fetch_negotiator_init(r, negotiator);
@@ -1134,9 +1118,10 @@ static struct ref *do_fetch_pack(struct fetch_pack_args *args,
 	else
 		alternate_shallow_file = NULL;
 	if (get_pack(args, fd, pack_lockfiles, NULL, sought, nr_sought,
-		     &gitmodules_oids))
+		     &fsck_options.gitmodules_found))
 		die(_("git fetch-pack: fetch failed."));
-	fsck_gitmodules_oids(&gitmodules_oids);
+	if (fsck_finish(&fsck_options))
+		die("fsck failed");
 
  all_done:
 	if (negotiator)
@@ -1587,7 +1572,6 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	struct string_list packfile_uris = STRING_LIST_INIT_DUP;
 	int i;
 	struct strvec index_pack_args = STRVEC_INIT;
-	struct oidset gitmodules_oids = OIDSET_INIT;
 
 	negotiator = &negotiator_alloc;
 	fetch_negotiator_init(r, negotiator);
@@ -1678,7 +1662,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 			process_section_header(&reader, "packfile", 0);
 			if (get_pack(args, fd, pack_lockfiles,
 				     packfile_uris.nr ? &index_pack_args : NULL,
-				     sought, nr_sought, &gitmodules_oids))
+				     sought, nr_sought, &fsck_options.gitmodules_found))
 				die(_("git fetch-pack: fetch failed."));
 			do_check_stateless_delimiter(args, &reader);
 
@@ -1721,7 +1705,7 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 
 		packname[the_hash_algo->hexsz] = '\0';
 
-		parse_gitmodules_oids(cmd.out, &gitmodules_oids);
+		parse_gitmodules_oids(cmd.out, &fsck_options.gitmodules_found);
 
 		close(cmd.out);
 
@@ -1742,7 +1726,8 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	string_list_clear(&packfile_uris, 0);
 	strvec_clear(&index_pack_args);
 
-	fsck_gitmodules_oids(&gitmodules_oids);
+	if (fsck_finish(&fsck_options))
+		die("fsck failed");
 
 	if (negotiator)
 		negotiator->release(negotiator);
diff --git a/fsck.c b/fsck.c
index e3030f3..f5ed6a2 100644
--- a/fsck.c
+++ b/fsck.c
@@ -19,90 +19,19 @@
 #include "credential.h"
 #include "help.h"
 
-static struct oidset gitmodules_found = OIDSET_INIT;
-static struct oidset gitmodules_done = OIDSET_INIT;
-
-#define FSCK_FATAL -1
-#define FSCK_INFO -2
-
-#define FOREACH_MSG_ID(FUNC) \
-	/* fatal errors */ \
-	FUNC(NUL_IN_HEADER, FATAL) \
-	FUNC(UNTERMINATED_HEADER, FATAL) \
-	/* errors */ \
-	FUNC(BAD_DATE, ERROR) \
-	FUNC(BAD_DATE_OVERFLOW, ERROR) \
-	FUNC(BAD_EMAIL, ERROR) \
-	FUNC(BAD_NAME, ERROR) \
-	FUNC(BAD_OBJECT_SHA1, ERROR) \
-	FUNC(BAD_PARENT_SHA1, ERROR) \
-	FUNC(BAD_TAG_OBJECT, ERROR) \
-	FUNC(BAD_TIMEZONE, ERROR) \
-	FUNC(BAD_TREE, ERROR) \
-	FUNC(BAD_TREE_SHA1, ERROR) \
-	FUNC(BAD_TYPE, ERROR) \
-	FUNC(DUPLICATE_ENTRIES, ERROR) \
-	FUNC(MISSING_AUTHOR, ERROR) \
-	FUNC(MISSING_COMMITTER, ERROR) \
-	FUNC(MISSING_EMAIL, ERROR) \
-	FUNC(MISSING_NAME_BEFORE_EMAIL, ERROR) \
-	FUNC(MISSING_OBJECT, ERROR) \
-	FUNC(MISSING_SPACE_BEFORE_DATE, ERROR) \
-	FUNC(MISSING_SPACE_BEFORE_EMAIL, ERROR) \
-	FUNC(MISSING_TAG, ERROR) \
-	FUNC(MISSING_TAG_ENTRY, ERROR) \
-	FUNC(MISSING_TREE, ERROR) \
-	FUNC(MISSING_TREE_OBJECT, ERROR) \
-	FUNC(MISSING_TYPE, ERROR) \
-	FUNC(MISSING_TYPE_ENTRY, ERROR) \
-	FUNC(MULTIPLE_AUTHORS, ERROR) \
-	FUNC(TREE_NOT_SORTED, ERROR) \
-	FUNC(UNKNOWN_TYPE, ERROR) \
-	FUNC(ZERO_PADDED_DATE, ERROR) \
-	FUNC(GITMODULES_MISSING, ERROR) \
-	FUNC(GITMODULES_BLOB, ERROR) \
-	FUNC(GITMODULES_LARGE, ERROR) \
-	FUNC(GITMODULES_NAME, ERROR) \
-	FUNC(GITMODULES_SYMLINK, ERROR) \
-	FUNC(GITMODULES_URL, ERROR) \
-	FUNC(GITMODULES_PATH, ERROR) \
-	FUNC(GITMODULES_UPDATE, ERROR) \
-	/* warnings */ \
-	FUNC(BAD_FILEMODE, WARN) \
-	FUNC(EMPTY_NAME, WARN) \
-	FUNC(FULL_PATHNAME, WARN) \
-	FUNC(HAS_DOT, WARN) \
-	FUNC(HAS_DOTDOT, WARN) \
-	FUNC(HAS_DOTGIT, WARN) \
-	FUNC(NULL_SHA1, WARN) \
-	FUNC(ZERO_PADDED_FILEMODE, WARN) \
-	FUNC(NUL_IN_COMMIT, WARN) \
-	/* infos (reported as warnings, but ignored by default) */ \
-	FUNC(GITMODULES_PARSE, INFO) \
-	FUNC(BAD_TAG_NAME, INFO) \
-	FUNC(MISSING_TAGGER_ENTRY, INFO) \
-	/* ignored (elevated when requested) */ \
-	FUNC(EXTRA_HEADER_ENTRY, IGNORE)
-
-#define MSG_ID(id, msg_type) FSCK_MSG_##id,
-enum fsck_msg_id {
-	FOREACH_MSG_ID(MSG_ID)
-	FSCK_MSG_MAX
-};
-#undef MSG_ID
-
 #define STR(x) #x
 #define MSG_ID(id, msg_type) { STR(id), NULL, NULL, FSCK_##msg_type },
 static struct {
 	const char *id_string;
 	const char *downcased;
 	const char *camelcased;
-	int msg_type;
+	enum fsck_msg_type msg_type;
 } msg_id_info[FSCK_MSG_MAX + 1] = {
-	FOREACH_MSG_ID(MSG_ID)
+	FOREACH_FSCK_MSG_ID(MSG_ID)
 	{ NULL, NULL, NULL, -1 }
 };
 #undef MSG_ID
+#undef STR
 
 static void prepare_msg_ids(void)
 {
@@ -164,25 +93,23 @@ void list_config_fsck_msg_ids(struct string_list *list, const char *prefix)
 		list_config_item(list, prefix, msg_id_info[i].camelcased);
 }
 
-static int fsck_msg_type(enum fsck_msg_id msg_id,
+static enum fsck_msg_type fsck_msg_type(enum fsck_msg_id msg_id,
 	struct fsck_options *options)
 {
-	int msg_type;
-
 	assert(msg_id >= 0 && msg_id < FSCK_MSG_MAX);
 
-	if (options->msg_type)
-		msg_type = options->msg_type[msg_id];
-	else {
-		msg_type = msg_id_info[msg_id].msg_type;
+	if (!options->msg_type) {
+		enum fsck_msg_type msg_type = msg_id_info[msg_id].msg_type;
+
 		if (options->strict && msg_type == FSCK_WARN)
 			msg_type = FSCK_ERROR;
+		return msg_type;
 	}
 
-	return msg_type;
+	return options->msg_type[msg_id];
 }
 
-static int parse_msg_type(const char *str)
+static enum fsck_msg_type parse_msg_type(const char *str)
 {
 	if (!strcmp(str, "error"))
 		return FSCK_ERROR;
@@ -202,28 +129,35 @@ int is_valid_msg_type(const char *msg_id, const char *msg_type)
 	return 1;
 }
 
-void fsck_set_msg_type(struct fsck_options *options,
-		const char *msg_id, const char *msg_type)
+void fsck_set_msg_type_from_ids(struct fsck_options *options,
+				enum fsck_msg_id msg_id,
+				enum fsck_msg_type msg_type)
 {
-	int id = parse_msg_id(msg_id), type;
-
-	if (id < 0)
-		die("Unhandled message id: %s", msg_id);
-	type = parse_msg_type(msg_type);
-
-	if (type != FSCK_ERROR && msg_id_info[id].msg_type == FSCK_FATAL)
-		die("Cannot demote %s to %s", msg_id, msg_type);
-
 	if (!options->msg_type) {
 		int i;
-		int *msg_type;
-		ALLOC_ARRAY(msg_type, FSCK_MSG_MAX);
+		enum fsck_msg_type *severity;
+		ALLOC_ARRAY(severity, FSCK_MSG_MAX);
 		for (i = 0; i < FSCK_MSG_MAX; i++)
-			msg_type[i] = fsck_msg_type(i, options);
-		options->msg_type = msg_type;
+			severity[i] = fsck_msg_type(i, options);
+		options->msg_type = severity;
 	}
 
-	options->msg_type[id] = type;
+	options->msg_type[msg_id] = msg_type;
+}
+
+void fsck_set_msg_type(struct fsck_options *options,
+		       const char *msg_id_str, const char *msg_type_str)
+{
+	int msg_id = parse_msg_id(msg_id_str);
+	enum fsck_msg_type msg_type = parse_msg_type(msg_type_str);
+
+	if (msg_id < 0)
+		die("Unhandled message id: %s", msg_id_str);
+
+	if (msg_type != FSCK_ERROR && msg_id_info[msg_id].msg_type == FSCK_FATAL)
+		die("Cannot demote %s to %s", msg_id_str, msg_type_str);
+
+	fsck_set_msg_type_from_ids(options, msg_id, msg_type);
 }
 
 void fsck_set_msg_types(struct fsck_options *options, const char *values)
@@ -264,24 +198,6 @@ void fsck_set_msg_types(struct fsck_options *options, const char *values)
 	free(to_free);
 }
 
-static void append_msg_id(struct strbuf *sb, const char *msg_id)
-{
-	for (;;) {
-		char c = *(msg_id)++;
-
-		if (!c)
-			break;
-		if (c != '_')
-			strbuf_addch(sb, tolower(c));
-		else {
-			assert(*msg_id);
-			strbuf_addch(sb, *(msg_id)++);
-		}
-	}
-
-	strbuf_addstr(sb, ": ");
-}
-
 static int object_on_skiplist(struct fsck_options *opts,
 			      const struct object_id *oid)
 {
@@ -291,11 +207,12 @@ static int object_on_skiplist(struct fsck_options *opts,
 __attribute__((format (printf, 5, 6)))
 static int report(struct fsck_options *options,
 		  const struct object_id *oid, enum object_type object_type,
-		  enum fsck_msg_id id, const char *fmt, ...)
+		  enum fsck_msg_id msg_id, const char *fmt, ...)
 {
 	va_list ap;
 	struct strbuf sb = STRBUF_INIT;
-	int msg_type = fsck_msg_type(id, options), result;
+	enum fsck_msg_type msg_type = fsck_msg_type(msg_id, options);
+	int result;
 
 	if (msg_type == FSCK_IGNORE)
 		return 0;
@@ -308,12 +225,13 @@ static int report(struct fsck_options *options,
 	else if (msg_type == FSCK_INFO)
 		msg_type = FSCK_WARN;
 
-	append_msg_id(&sb, msg_id_info[id].id_string);
+	prepare_msg_ids();
+	strbuf_addf(&sb, "%s: ", msg_id_info[msg_id].camelcased);
 
 	va_start(ap, fmt);
 	strbuf_vaddf(&sb, fmt, ap);
 	result = options->error_func(options, oid, object_type,
-				     msg_type, sb.buf);
+				     msg_type, msg_id, sb.buf);
 	strbuf_release(&sb);
 	va_end(ap);
 
@@ -685,7 +603,7 @@ static int fsck_tree(const struct object_id *oid,
 
 		if (is_hfs_dotgitmodules(name) || is_ntfs_dotgitmodules(name)) {
 			if (!S_ISLNK(mode))
-				oidset_insert(&gitmodules_found, oid);
+				oidset_insert(&options->gitmodules_found, oid);
 			else
 				retval += report(options,
 						 oid, OBJ_TREE,
@@ -699,7 +617,7 @@ static int fsck_tree(const struct object_id *oid,
 				has_dotgit |= is_ntfs_dotgit(backslash);
 				if (is_ntfs_dotgitmodules(backslash)) {
 					if (!S_ISLNK(mode))
-						oidset_insert(&gitmodules_found, oid);
+						oidset_insert(&options->gitmodules_found, oid);
 					else
 						retval += report(options, oid, OBJ_TREE,
 								 FSCK_MSG_GITMODULES_SYMLINK,
@@ -1211,9 +1129,9 @@ static int fsck_blob(const struct object_id *oid, const char *buf,
 	struct fsck_gitmodules_data data;
 	struct config_options config_opts = { 0 };
 
-	if (!oidset_contains(&gitmodules_found, oid))
+	if (!oidset_contains(&options->gitmodules_found, oid))
 		return 0;
-	oidset_insert(&gitmodules_done, oid);
+	oidset_insert(&options->gitmodules_done, oid);
 
 	if (object_on_skiplist(options, oid))
 		return 0;
@@ -1266,7 +1184,9 @@ int fsck_object(struct object *obj, void *data, unsigned long size,
 int fsck_error_function(struct fsck_options *o,
 			const struct object_id *oid,
 			enum object_type object_type,
-			int msg_type, const char *message)
+			enum fsck_msg_type msg_type,
+			enum fsck_msg_id msg_id,
+			const char *message)
 {
 	if (msg_type == FSCK_WARN) {
 		warning("object %s: %s", fsck_describe_object(o, oid), message);
@@ -1276,24 +1196,19 @@ int fsck_error_function(struct fsck_options *o,
 	return 1;
 }
 
-void register_found_gitmodules(const struct object_id *oid)
-{
-	oidset_insert(&gitmodules_found, oid);
-}
-
 int fsck_finish(struct fsck_options *options)
 {
 	int ret = 0;
 	struct oidset_iter iter;
 	const struct object_id *oid;
 
-	oidset_iter_init(&gitmodules_found, &iter);
+	oidset_iter_init(&options->gitmodules_found, &iter);
 	while ((oid = oidset_iter_next(&iter))) {
 		enum object_type type;
 		unsigned long size;
 		char *buf;
 
-		if (oidset_contains(&gitmodules_done, oid))
+		if (oidset_contains(&options->gitmodules_done, oid))
 			continue;
 
 		buf = read_object_file(oid, &type, &size);
@@ -1318,14 +1233,14 @@ int fsck_finish(struct fsck_options *options)
 	}
 
 
-	oidset_clear(&gitmodules_found);
-	oidset_clear(&gitmodules_done);
+	oidset_clear(&options->gitmodules_found);
+	oidset_clear(&options->gitmodules_done);
 	return ret;
 }
 
-int fsck_config_internal(const char *var, const char *value, void *cb,
-			 struct fsck_options *options)
+int git_fsck_config(const char *var, const char *value, void *cb)
 {
+	struct fsck_options *options = cb;
 	if (strcmp(var, "fsck.skiplist") == 0) {
 		const char *path;
 		struct strbuf sb = STRBUF_INIT;
@@ -1346,3 +1261,21 @@ int fsck_config_internal(const char *var, const char *value, void *cb,
 
 	return git_default_config(var, value, cb);
 }
+
+/*
+ * Custom error callbacks that are used in more than one place.
+ */
+
+int fsck_error_cb_print_missing_gitmodules(struct fsck_options *o,
+					   const struct object_id *oid,
+					   enum object_type object_type,
+					   enum fsck_msg_type msg_type,
+					   enum fsck_msg_id msg_id,
+					   const char *message)
+{
+	if (msg_id == FSCK_MSG_GITMODULES_MISSING) {
+		puts(oid_to_hex(oid));
+		return 0;
+	}
+	return fsck_error_function(o, oid, object_type, msg_type, msg_id, message);
+}
diff --git a/fsck.h b/fsck.h
index 733378f..7202c3c 100644
--- a/fsck.h
+++ b/fsck.h
@@ -3,15 +3,90 @@
 
 #include "oidset.h"
 
-#define FSCK_ERROR 1
-#define FSCK_WARN 2
-#define FSCK_IGNORE 3
+enum fsck_msg_type {
+	/* for internal use only */
+	FSCK_IGNORE,
+	FSCK_INFO,
+	FSCK_FATAL,
+	/* "public", fed to e.g. error_func callbacks */
+	FSCK_ERROR,
+	FSCK_WARN,
+};
+
+#define FOREACH_FSCK_MSG_ID(FUNC) \
+	/* fatal errors */ \
+	FUNC(NUL_IN_HEADER, FATAL) \
+	FUNC(UNTERMINATED_HEADER, FATAL) \
+	/* errors */ \
+	FUNC(BAD_DATE, ERROR) \
+	FUNC(BAD_DATE_OVERFLOW, ERROR) \
+	FUNC(BAD_EMAIL, ERROR) \
+	FUNC(BAD_NAME, ERROR) \
+	FUNC(BAD_OBJECT_SHA1, ERROR) \
+	FUNC(BAD_PARENT_SHA1, ERROR) \
+	FUNC(BAD_TAG_OBJECT, ERROR) \
+	FUNC(BAD_TIMEZONE, ERROR) \
+	FUNC(BAD_TREE, ERROR) \
+	FUNC(BAD_TREE_SHA1, ERROR) \
+	FUNC(BAD_TYPE, ERROR) \
+	FUNC(DUPLICATE_ENTRIES, ERROR) \
+	FUNC(MISSING_AUTHOR, ERROR) \
+	FUNC(MISSING_COMMITTER, ERROR) \
+	FUNC(MISSING_EMAIL, ERROR) \
+	FUNC(MISSING_NAME_BEFORE_EMAIL, ERROR) \
+	FUNC(MISSING_OBJECT, ERROR) \
+	FUNC(MISSING_SPACE_BEFORE_DATE, ERROR) \
+	FUNC(MISSING_SPACE_BEFORE_EMAIL, ERROR) \
+	FUNC(MISSING_TAG, ERROR) \
+	FUNC(MISSING_TAG_ENTRY, ERROR) \
+	FUNC(MISSING_TREE, ERROR) \
+	FUNC(MISSING_TREE_OBJECT, ERROR) \
+	FUNC(MISSING_TYPE, ERROR) \
+	FUNC(MISSING_TYPE_ENTRY, ERROR) \
+	FUNC(MULTIPLE_AUTHORS, ERROR) \
+	FUNC(TREE_NOT_SORTED, ERROR) \
+	FUNC(UNKNOWN_TYPE, ERROR) \
+	FUNC(ZERO_PADDED_DATE, ERROR) \
+	FUNC(GITMODULES_MISSING, ERROR) \
+	FUNC(GITMODULES_BLOB, ERROR) \
+	FUNC(GITMODULES_LARGE, ERROR) \
+	FUNC(GITMODULES_NAME, ERROR) \
+	FUNC(GITMODULES_SYMLINK, ERROR) \
+	FUNC(GITMODULES_URL, ERROR) \
+	FUNC(GITMODULES_PATH, ERROR) \
+	FUNC(GITMODULES_UPDATE, ERROR) \
+	/* warnings */ \
+	FUNC(BAD_FILEMODE, WARN) \
+	FUNC(EMPTY_NAME, WARN) \
+	FUNC(FULL_PATHNAME, WARN) \
+	FUNC(HAS_DOT, WARN) \
+	FUNC(HAS_DOTDOT, WARN) \
+	FUNC(HAS_DOTGIT, WARN) \
+	FUNC(NULL_SHA1, WARN) \
+	FUNC(ZERO_PADDED_FILEMODE, WARN) \
+	FUNC(NUL_IN_COMMIT, WARN) \
+	/* infos (reported as warnings, but ignored by default) */ \
+	FUNC(GITMODULES_PARSE, INFO) \
+	FUNC(BAD_TAG_NAME, INFO) \
+	FUNC(MISSING_TAGGER_ENTRY, INFO) \
+	/* ignored (elevated when requested) */ \
+	FUNC(EXTRA_HEADER_ENTRY, IGNORE)
+
+#define MSG_ID(id, msg_type) FSCK_MSG_##id,
+enum fsck_msg_id {
+	FOREACH_FSCK_MSG_ID(MSG_ID)
+	FSCK_MSG_MAX
+};
+#undef MSG_ID
 
 struct fsck_options;
 struct object;
 
+void fsck_set_msg_type_from_ids(struct fsck_options *options,
+				enum fsck_msg_id msg_id,
+				enum fsck_msg_type msg_type);
 void fsck_set_msg_type(struct fsck_options *options,
-		const char *msg_id, const char *msg_type);
+		       const char *msg_id, const char *msg_type);
 void fsck_set_msg_types(struct fsck_options *options, const char *values);
 int is_valid_msg_type(const char *msg_id, const char *msg_type);
 
@@ -23,28 +98,55 @@ int is_valid_msg_type(const char *msg_id, const char *msg_type);
  *     <0	error signaled and abort
  *     >0	error signaled and do not abort
  */
-typedef int (*fsck_walk_func)(struct object *obj, int type, void *data, struct fsck_options *options);
+typedef int (*fsck_walk_func)(struct object *obj, enum object_type object_type,
+			      void *data, struct fsck_options *options);
 
 /* callback for fsck_object, type is FSCK_ERROR or FSCK_WARN */
 typedef int (*fsck_error)(struct fsck_options *o,
 			  const struct object_id *oid, enum object_type object_type,
-			  int msg_type, const char *message);
+			  enum fsck_msg_type msg_type, enum fsck_msg_id msg_id,
+			  const char *message);
 
 int fsck_error_function(struct fsck_options *o,
 			const struct object_id *oid, enum object_type object_type,
-			int msg_type, const char *message);
+			enum fsck_msg_type msg_type, enum fsck_msg_id msg_id,
+			const char *message);
+int fsck_error_cb_print_missing_gitmodules(struct fsck_options *o,
+					   const struct object_id *oid,
+					   enum object_type object_type,
+					   enum fsck_msg_type msg_type,
+					   enum fsck_msg_id msg_id,
+					   const char *message);
 
 struct fsck_options {
 	fsck_walk_func walk;
 	fsck_error error_func;
 	unsigned strict:1;
-	int *msg_type;
+	enum fsck_msg_type *msg_type;
 	struct oidset skiplist;
+	struct oidset gitmodules_found;
+	struct oidset gitmodules_done;
 	kh_oid_map_t *object_names;
 };
 
-#define FSCK_OPTIONS_DEFAULT { NULL, fsck_error_function, 0, NULL, OIDSET_INIT }
-#define FSCK_OPTIONS_STRICT { NULL, fsck_error_function, 1, NULL, OIDSET_INIT }
+#define FSCK_OPTIONS_DEFAULT { \
+	.skiplist = OIDSET_INIT, \
+	.gitmodules_found = OIDSET_INIT, \
+	.gitmodules_done = OIDSET_INIT, \
+	.error_func = fsck_error_function \
+}
+#define FSCK_OPTIONS_STRICT { \
+	.strict = 1, \
+	.gitmodules_found = OIDSET_INIT, \
+	.gitmodules_done = OIDSET_INIT, \
+	.error_func = fsck_error_function, \
+}
+#define FSCK_OPTIONS_MISSING_GITMODULES { \
+	.strict = 1, \
+	.gitmodules_found = OIDSET_INIT, \
+	.gitmodules_done = OIDSET_INIT, \
+	.error_func = fsck_error_cb_print_missing_gitmodules, \
+}
 
 /* descend in all linked child objects
  * the return value is:
@@ -62,8 +164,6 @@ int fsck_walk(struct object *obj, void *data, struct fsck_options *options);
 int fsck_object(struct object *obj, void *data, unsigned long size,
 	struct fsck_options *options);
 
-void register_found_gitmodules(const struct object_id *oid);
-
 /*
  * fsck a tag, and pass info about it back to the caller. This is
  * exposed fsck_object() internals for git-mktag(1).
@@ -109,7 +209,6 @@ const char *fsck_describe_object(struct fsck_options *options,
  * git_config() callback for use by fsck-y tools that want to support
  * fsck.<msg> fsck.skipList etc.
  */
-int fsck_config_internal(const char *var, const char *value, void *cb,
-			 struct fsck_options *options);
+int git_fsck_config(const char *var, const char *value, void *cb);
 
 #endif