diff --git a/fsck.c b/fsck.c
index 2309c40a11430e..465247be71fc4d 100644
--- a/fsck.c
+++ b/fsck.c
@@ -283,9 +283,10 @@ static int object_on_skiplist(struct fsck_options *opts,
 	return opts && oid && oidset_contains(&opts->skiplist, oid);
 }
 
-__attribute__((format (printf, 4, 5)))
-static int report(struct fsck_options *options, struct object *object,
-	enum fsck_msg_id id, const char *fmt, ...)
+__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, ...)
 {
 	va_list ap;
 	struct strbuf sb = STRBUF_INIT;
@@ -294,7 +295,7 @@ static int report(struct fsck_options *options, struct object *object,
 	if (msg_type == FSCK_IGNORE)
 		return 0;
 
-	if (object_on_skiplist(options, &object->oid))
+	if (object_on_skiplist(options, oid))
 		return 0;
 
 	if (msg_type == FSCK_FATAL)
@@ -306,7 +307,7 @@ static int report(struct fsck_options *options, struct object *object,
 
 	va_start(ap, fmt);
 	strbuf_vaddf(&sb, fmt, ap);
-	result = options->error_func(options, &object->oid, object->type,
+	result = options->error_func(options, oid, object_type,
 				     msg_type, sb.buf);
 	strbuf_release(&sb);
 	va_end(ap);
@@ -585,7 +586,7 @@ static int fsck_tree(struct tree *item,
 	const char *o_name;
 
 	if (init_tree_desc_gently(&desc, buffer, size)) {
-		retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 		return retval;
 	}
 
@@ -611,13 +612,14 @@ static int fsck_tree(struct tree *item,
 			if (!S_ISLNK(mode))
 				oidset_insert(&gitmodules_found, oid);
 			else
-				retval += report(options, &item->object,
+				retval += report(options,
+						 &item->object.oid, item->object.type,
 						 FSCK_MSG_GITMODULES_SYMLINK,
 						 ".gitmodules is a symbolic link");
 		}
 
 		if (update_tree_entry_gently(&desc)) {
-			retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+			retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 			break;
 		}
 
@@ -662,25 +664,25 @@ static int fsck_tree(struct tree *item,
 	}
 
 	if (has_null_sha1)
-		retval += report(options, &item->object, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
 	if (has_full_path)
-		retval += report(options, &item->object, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
 	if (has_empty_name)
-		retval += report(options, &item->object, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
 	if (has_dot)
-		retval += report(options, &item->object, FSCK_MSG_HAS_DOT, "contains '.'");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_HAS_DOT, "contains '.'");
 	if (has_dotdot)
-		retval += report(options, &item->object, FSCK_MSG_HAS_DOTDOT, "contains '..'");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_HAS_DOTDOT, "contains '..'");
 	if (has_dotgit)
-		retval += report(options, &item->object, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
 	if (has_zero_pad)
-		retval += report(options, &item->object, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
 	if (has_bad_modes)
-		retval += report(options, &item->object, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
 	if (has_dup_entries)
-		retval += report(options, &item->object, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
 	if (not_properly_sorted)
-		retval += report(options, &item->object, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
+		retval += report(options, &item->object.oid, item->object.type, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
 	return retval;
 }
 
@@ -693,7 +695,7 @@ static int verify_headers(const void *data, unsigned long size,
 	for (i = 0; i < size; i++) {
 		switch (buffer[i]) {
 		case '\0':
-			return report(options, obj,
+			return report(options, &obj->oid, obj->type,
 				FSCK_MSG_NUL_IN_HEADER,
 				"unterminated header: NUL at offset %ld", i);
 		case '\n':
@@ -711,7 +713,7 @@ static int verify_headers(const void *data, unsigned long size,
 	if (size && buffer[size - 1] == '\n')
 		return 0;
 
-	return report(options, obj,
+	return report(options, &obj->oid, obj->type,
 		FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
 }
 
@@ -725,28 +727,28 @@ static int fsck_ident(const char **ident, struct object *obj, struct fsck_option
 		(*ident)++;
 
 	if (*p == '<')
-		return report(options, obj, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 	p += strcspn(p, "<>\n");
 	if (*p == '>')
-		return report(options, obj, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
 	if (*p != '<')
-		return report(options, obj, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
 	if (p[-1] != ' ')
-		return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 	p++;
 	p += strcspn(p, "<>\n");
 	if (*p != '>')
-		return report(options, obj, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
 	p++;
 	if (*p != ' ')
-		return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
 	p++;
 	if (*p == '0' && p[1] != ' ')
-		return report(options, obj, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
 	if (date_overflows(parse_timestamp(p, &end, 10)))
-		return report(options, obj, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
 	if ((end == p || *end != ' '))
-		return report(options, obj, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
 	p = end + 1;
 	if ((*p != '+' && *p != '-') ||
 	    !isdigit(p[1]) ||
@@ -754,7 +756,7 @@ static int fsck_ident(const char **ident, struct object *obj, struct fsck_option
 	    !isdigit(p[3]) ||
 	    !isdigit(p[4]) ||
 	    (p[5] != '\n'))
-		return report(options, obj, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
+		return report(options, &obj->oid, obj->type, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
 	p += 6;
 	return 0;
 }
@@ -772,16 +774,16 @@ static int fsck_commit(struct commit *commit, const char *buffer,
 		return -1;
 
 	if (!skip_prefix(buffer, "tree ", &buffer))
-		return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
+		return report(options, &commit->object.oid, commit->object.type, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
 	if (parse_oid_hex(buffer, &tree_oid, &p) || *p != '\n') {
-		err = report(options, &commit->object, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
+		err = report(options, &commit->object.oid, commit->object.type, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
 		if (err)
 			return err;
 	}
 	buffer = p + 1;
 	while (skip_prefix(buffer, "parent ", &buffer)) {
 		if (parse_oid_hex(buffer, &oid, &p) || *p != '\n') {
-			err = report(options, &commit->object, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
+			err = report(options, &commit->object.oid, commit->object.type, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
 			if (err)
 				return err;
 		}
@@ -795,18 +797,18 @@ static int fsck_commit(struct commit *commit, const char *buffer,
 			return err;
 	}
 	if (author_count < 1)
-		err = report(options, &commit->object, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
+		err = report(options, &commit->object.oid, commit->object.type, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
 	else if (author_count > 1)
-		err = report(options, &commit->object, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
+		err = report(options, &commit->object.oid, commit->object.type, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
 	if (err)
 		return err;
 	if (!skip_prefix(buffer, "committer ", &buffer))
-		return report(options, &commit->object, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
+		return report(options, &commit->object.oid, commit->object.type, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
 	err = fsck_ident(&buffer, &commit->object, options);
 	if (err)
 		return err;
 	if (memchr(buffer_begin, '\0', size)) {
-		err = report(options, &commit->object, FSCK_MSG_NUL_IN_COMMIT,
+		err = report(options, &commit->object.oid, commit->object.type, FSCK_MSG_NUL_IN_COMMIT,
 			     "NUL byte in the commit object body");
 		if (err)
 			return err;
@@ -828,45 +830,46 @@ static int fsck_tag(struct tag *tag, const char *buffer,
 		goto done;
 
 	if (!skip_prefix(buffer, "object ", &buffer)) {
-		ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 		goto done;
 	}
 	if (parse_oid_hex(buffer, &oid, &p) || *p != '\n') {
-		ret = report(options, &tag->object, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
 		if (ret)
 			goto done;
 	}
 	buffer = p + 1;
 
 	if (!skip_prefix(buffer, "type ", &buffer)) {
-		ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
 		goto done;
 	}
 	eol = strchr(buffer, '\n');
 	if (!eol) {
-		ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
 		goto done;
 	}
 	if (type_from_string_gently(buffer, eol - buffer, 1) < 0)
-		ret = report(options, &tag->object, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
 	if (ret)
 		goto done;
 	buffer = eol + 1;
 
 	if (!skip_prefix(buffer, "tag ", &buffer)) {
-		ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
 		goto done;
 	}
 	eol = strchr(buffer, '\n');
 	if (!eol) {
-		ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
 		goto done;
 	}
 	strbuf_addf(&sb, "refs/tags/%.*s", (int)(eol - buffer), buffer);
 	if (check_refname_format(sb.buf, 0)) {
-		ret = report(options, &tag->object, FSCK_MSG_BAD_TAG_NAME,
-			   "invalid 'tag' name: %.*s",
-			   (int)(eol - buffer), buffer);
+		ret = report(options, &tag->object.oid, tag->object.type,
+			     FSCK_MSG_BAD_TAG_NAME,
+			     "invalid 'tag' name: %.*s",
+			     (int)(eol - buffer), buffer);
 		if (ret)
 			goto done;
 	}
@@ -874,7 +877,7 @@ static int fsck_tag(struct tag *tag, const char *buffer,
 
 	if (!skip_prefix(buffer, "tagger ", &buffer)) {
 		/* early tags do not contain 'tagger' lines; warn only */
-		ret = report(options, &tag->object, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
+		ret = report(options, &tag->object.oid, tag->object.type, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
 		if (ret)
 			goto done;
 	}
@@ -905,19 +908,22 @@ static int fsck_gitmodules_fn(const char *var, const char *value, void *vdata)
 
 	name = xmemdupz(subsection, subsection_len);
 	if (check_submodule_name(name) < 0)
-		data->ret |= report(data->options, data->obj,
+		data->ret |= report(data->options,
+				    &data->obj->oid, data->obj->type,
 				    FSCK_MSG_GITMODULES_NAME,
 				    "disallowed submodule name: %s",
 				    name);
 	if (!strcmp(key, "url") && value &&
 	    looks_like_command_line_option(value))
-		data->ret |= report(data->options, data->obj,
+		data->ret |= report(data->options,
+				    &data->obj->oid, data->obj->type,
 				    FSCK_MSG_GITMODULES_URL,
 				    "disallowed submodule url: %s",
 				    value);
 	if (!strcmp(key, "path") && value &&
 	    looks_like_command_line_option(value))
-		data->ret |= report(data->options, data->obj,
+		data->ret |= report(data->options,
+				    &data->obj->oid, data->obj->type,
 				    FSCK_MSG_GITMODULES_PATH,
 				    "disallowed submodule path: %s",
 				    value);
@@ -945,7 +951,7 @@ static int fsck_blob(struct blob *blob, const char *buf,
 		 * blob too gigantic to load into memory. Let's just consider
 		 * that an error.
 		 */
-		return report(options, &blob->object,
+		return report(options, &blob->object.oid, blob->object.type,
 			      FSCK_MSG_GITMODULES_LARGE,
 			      ".gitmodules too large to parse");
 	}
@@ -956,7 +962,7 @@ static int fsck_blob(struct blob *blob, const char *buf,
 	config_opts.error_action = CONFIG_ERROR_SILENT;
 	if (git_config_from_mem(fsck_gitmodules_fn, CONFIG_ORIGIN_BLOB,
 				".gitmodules", buf, size, &data, &config_opts))
-		data.ret |= report(options, &blob->object,
+		data.ret |= report(options, &blob->object.oid, blob->object.type,
 				   FSCK_MSG_GITMODULES_PARSE,
 				   "could not parse gitmodules blob");
 
@@ -967,7 +973,7 @@ int fsck_object(struct object *obj, void *data, unsigned long size,
 	struct fsck_options *options)
 {
 	if (!obj)
-		return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
+		return report(options, NULL, OBJ_NONE, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
 
 	if (obj->type == OBJ_BLOB)
 		return fsck_blob((struct blob *)obj, data, size, options);
@@ -980,8 +986,10 @@ int fsck_object(struct object *obj, void *data, unsigned long size,
 		return fsck_tag((struct tag *) obj, (const char *) data,
 			size, options);
 
-	return report(options, obj, FSCK_MSG_UNKNOWN_TYPE, "unknown type '%d' (internal fsck error)",
-			  obj->type);
+	return report(options, &obj->oid, obj->type,
+		      FSCK_MSG_UNKNOWN_TYPE,
+		      "unknown type '%d' (internal fsck error)",
+		      obj->type);
 }
 
 int fsck_error_function(struct fsck_options *o,
@@ -1016,7 +1024,7 @@ int fsck_finish(struct fsck_options *options)
 		blob = lookup_blob(the_repository, oid);
 		if (!blob) {
 			struct object *obj = lookup_unknown_object(oid);
-			ret |= report(options, obj,
+			ret |= report(options, &obj->oid, obj->type,
 				      FSCK_MSG_GITMODULES_BLOB,
 				      "non-blob found at .gitmodules");
 			continue;
@@ -1026,7 +1034,8 @@ int fsck_finish(struct fsck_options *options)
 		if (!buf) {
 			if (is_promisor_object(&blob->object.oid))
 				continue;
-			ret |= report(options, &blob->object,
+			ret |= report(options,
+				      &blob->object.oid, blob->object.type,
 				      FSCK_MSG_GITMODULES_MISSING,
 				      "unable to read .gitmodules blob");
 			continue;
@@ -1035,7 +1044,8 @@ int fsck_finish(struct fsck_options *options)
 		if (type == OBJ_BLOB)
 			ret |= fsck_blob(blob, buf, size, options);
 		else
-			ret |= report(options, &blob->object,
+			ret |= report(options,
+				      &blob->object.oid, blob->object.type,
 				      FSCK_MSG_GITMODULES_BLOB,
 				      "non-blob found at .gitmodules");
 		free(buf);