revert(3p/git): Revert merge of git upstream at v2.26.2 r/852

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232de5bfa959ad6ebbb4c8192ac513352, reversing
changes made to f2b211131f2347342dde63975b09cf603149f1a3.

1 files changed, 210 insertions, 338 deletions

diff --git a/third_party/git/fsck.c b/third_party/git/fsck.c
index 73f30773f28a..cdb7d8db0301 100644
--- a/third_party/git/fsck.c
+++ b/third_party/git/fsck.c
@@ -9,14 +9,12 @@
 #include "tag.h"
 #include "fsck.h"
 #include "refs.h"
-#include "url.h"
 #include "utf8.h"
 #include "decorate.h"
 #include "oidset.h"
 #include "packfile.h"
 #include "submodule-config.h"
 #include "config.h"
-#include "credential.h"
 #include "help.h"
 
 static struct oidset gitmodules_found = OIDSET_INIT;
@@ -45,17 +43,21 @@ static struct oidset gitmodules_done = OIDSET_INIT;
 	FUNC(MISSING_AUTHOR, ERROR) \
 	FUNC(MISSING_COMMITTER, ERROR) \
 	FUNC(MISSING_EMAIL, ERROR) \
+	FUNC(MISSING_GRAFT, ERROR) \
 	FUNC(MISSING_NAME_BEFORE_EMAIL, ERROR) \
 	FUNC(MISSING_OBJECT, ERROR) \
+	FUNC(MISSING_PARENT, ERROR) \
 	FUNC(MISSING_SPACE_BEFORE_DATE, ERROR) \
 	FUNC(MISSING_SPACE_BEFORE_EMAIL, ERROR) \
 	FUNC(MISSING_TAG, ERROR) \
 	FUNC(MISSING_TAG_ENTRY, ERROR) \
+	FUNC(MISSING_TAG_OBJECT, ERROR) \
 	FUNC(MISSING_TREE, ERROR) \
 	FUNC(MISSING_TREE_OBJECT, ERROR) \
 	FUNC(MISSING_TYPE, ERROR) \
 	FUNC(MISSING_TYPE_ENTRY, ERROR) \
 	FUNC(MULTIPLE_AUTHORS, ERROR) \
+	FUNC(TAG_OBJECT_NOT_TAG, ERROR) \
 	FUNC(TREE_NOT_SORTED, ERROR) \
 	FUNC(UNKNOWN_TYPE, ERROR) \
 	FUNC(ZERO_PADDED_DATE, ERROR) \
@@ -66,7 +68,6 @@ static struct oidset gitmodules_done = OIDSET_INIT;
 	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) \
@@ -280,16 +281,14 @@ static void append_msg_id(struct strbuf *sb, const char *msg_id)
 	strbuf_addstr(sb, ": ");
 }
 
-static int object_on_skiplist(struct fsck_options *opts,
-			      const struct object_id *oid)
+static int object_on_skiplist(struct fsck_options *opts, struct object *obj)
 {
-	return opts && oid && oidset_contains(&opts->skiplist, oid);
+	return opts && obj && oidset_contains(&opts->skiplist, &obj->oid);
 }
 
-__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, ...)
+__attribute__((format (printf, 4, 5)))
+static int report(struct fsck_options *options, struct object *object,
+	enum fsck_msg_id id, const char *fmt, ...)
 {
 	va_list ap;
 	struct strbuf sb = STRBUF_INIT;
@@ -298,7 +297,7 @@ static int report(struct fsck_options *options,
 	if (msg_type == FSCK_IGNORE)
 		return 0;
 
-	if (object_on_skiplist(options, oid))
+	if (object_on_skiplist(options, object))
 		return 0;
 
 	if (msg_type == FSCK_FATAL)
@@ -310,71 +309,49 @@ static int report(struct fsck_options *options,
 
 	va_start(ap, fmt);
 	strbuf_vaddf(&sb, fmt, ap);
-	result = options->error_func(options, oid, object_type,
-				     msg_type, sb.buf);
+	result = options->error_func(options, object, msg_type, sb.buf);
 	strbuf_release(&sb);
 	va_end(ap);
 
 	return result;
 }
 
-void fsck_enable_object_names(struct fsck_options *options)
+static char *get_object_name(struct fsck_options *options, struct object *obj)
 {
 	if (!options->object_names)
-		options->object_names = kh_init_oid_map();
-}
-
-const char *fsck_get_object_name(struct fsck_options *options,
-				 const struct object_id *oid)
-{
-	khiter_t pos;
-	if (!options->object_names)
-		return NULL;
-	pos = kh_get_oid_map(options->object_names, *oid);
-	if (pos >= kh_end(options->object_names))
 		return NULL;
-	return kh_value(options->object_names, pos);
+	return lookup_decoration(options->object_names, obj);
 }
 
-void fsck_put_object_name(struct fsck_options *options,
-			  const struct object_id *oid,
-			  const char *fmt, ...)
+static void put_object_name(struct fsck_options *options, struct object *obj,
+	const char *fmt, ...)
 {
 	va_list ap;
 	struct strbuf buf = STRBUF_INIT;
-	khiter_t pos;
-	int hashret;
+	char *existing;
 
 	if (!options->object_names)
 		return;
-
-	pos = kh_put_oid_map(options->object_names, *oid, &hashret);
-	if (!hashret)
+	existing = lookup_decoration(options->object_names, obj);
+	if (existing)
 		return;
 	va_start(ap, fmt);
 	strbuf_vaddf(&buf, fmt, ap);
-	kh_value(options->object_names, pos) = strbuf_detach(&buf, NULL);
+	add_decoration(options->object_names, obj, strbuf_detach(&buf, NULL));
 	va_end(ap);
 }
 
-const char *fsck_describe_object(struct fsck_options *options,
-				 const struct object_id *oid)
+static const char *describe_object(struct fsck_options *o, struct object *obj)
 {
-	static struct strbuf bufs[] = {
-		STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
-	};
-	static int b = 0;
-	struct strbuf *buf;
-	const char *name = fsck_get_object_name(options, oid);
-
-	buf = bufs + b;
-	b = (b + 1) % ARRAY_SIZE(bufs);
-	strbuf_reset(buf);
-	strbuf_addstr(buf, oid_to_hex(oid));
-	if (name)
-		strbuf_addf(buf, " (%s)", name);
+	static struct strbuf buf = STRBUF_INIT;
+	char *name;
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, oid_to_hex(&obj->oid));
+	if (o->object_names && (name = lookup_decoration(o->object_names, obj)))
+		strbuf_addf(&buf, " (%s)", name);
 
-	return buf->buf;
+	return buf.buf;
 }
 
 static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *options)
@@ -387,7 +364,7 @@ static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *op
 	if (parse_tree(tree))
 		return -1;
 
-	name = fsck_get_object_name(options, &tree->object.oid);
+	name = get_object_name(options, &tree->object);
 	if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
 		return -1;
 	while (tree_entry_gently(&desc, &entry)) {
@@ -400,21 +377,20 @@ static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *op
 		if (S_ISDIR(entry.mode)) {
 			obj = (struct object *)lookup_tree(the_repository, &entry.oid);
 			if (name && obj)
-				fsck_put_object_name(options, &entry.oid, "%s%s/",
-						     name, entry.path);
+				put_object_name(options, obj, "%s%s/", name,
+					entry.path);
 			result = options->walk(obj, OBJ_TREE, data, options);
 		}
 		else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode)) {
 			obj = (struct object *)lookup_blob(the_repository, &entry.oid);
 			if (name && obj)
-				fsck_put_object_name(options, &entry.oid, "%s%s",
-						     name, entry.path);
+				put_object_name(options, obj, "%s%s", name,
+					entry.path);
 			result = options->walk(obj, OBJ_BLOB, data, options);
 		}
 		else {
 			result = error("in tree %s: entry %s has bad mode %.6o",
-				       fsck_describe_object(options, &tree->object.oid),
-				       entry.path, entry.mode);
+					describe_object(options, &tree->object), entry.path, entry.mode);
 		}
 		if (result < 0)
 			return result;
@@ -435,10 +411,10 @@ static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_optio
 	if (parse_commit(commit))
 		return -1;
 
-	name = fsck_get_object_name(options, &commit->object.oid);
+	name = get_object_name(options, &commit->object);
 	if (name)
-		fsck_put_object_name(options, get_commit_tree_oid(commit),
-				     "%s:", name);
+		put_object_name(options, &get_commit_tree(commit)->object,
+				"%s:", name);
 
 	result = options->walk((struct object *)get_commit_tree(commit),
 			       OBJ_TREE, data, options);
@@ -466,17 +442,16 @@ static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_optio
 
 	while (parents) {
 		if (name) {
-			struct object_id *oid = &parents->item->object.oid;
+			struct object *obj = &parents->item->object;
 
 			if (counter++)
-				fsck_put_object_name(options, oid, "%s^%d",
-						     name, counter);
+				put_object_name(options, obj, "%s^%d",
+					name, counter);
 			else if (generation > 0)
-				fsck_put_object_name(options, oid, "%.*s~%d",
-						     name_prefix_len, name,
-						     generation + 1);
+				put_object_name(options, obj, "%.*s~%d",
+					name_prefix_len, name, generation + 1);
 			else
-				fsck_put_object_name(options, oid, "%s^", name);
+				put_object_name(options, obj, "%s^", name);
 		}
 		result = options->walk((struct object *)parents->item, OBJ_COMMIT, data, options);
 		if (result < 0)
@@ -490,12 +465,12 @@ static int fsck_walk_commit(struct commit *commit, void *data, struct fsck_optio
 
 static int fsck_walk_tag(struct tag *tag, void *data, struct fsck_options *options)
 {
-	const char *name = fsck_get_object_name(options, &tag->object.oid);
+	char *name = get_object_name(options, &tag->object);
 
 	if (parse_tag(tag))
 		return -1;
 	if (name)
-		fsck_put_object_name(options, &tag->tagged->oid, "%s", name);
+		put_object_name(options, tag->tagged, "%s", name);
 	return options->walk(tag->tagged, OBJ_ANY, data, options);
 }
 
@@ -517,8 +492,7 @@ int fsck_walk(struct object *obj, void *data, struct fsck_options *options)
 	case OBJ_TAG:
 		return fsck_walk_tag((struct tag *)obj, data, options);
 	default:
-		error("Unknown object type for %s",
-		      fsck_describe_object(options, &obj->oid));
+		error("Unknown object type for %s", describe_object(options, obj));
 		return -1;
 	}
 }
@@ -569,9 +543,7 @@ static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, con
 	return c1 < c2 ? 0 : TREE_UNORDERED;
 }
 
-static int fsck_tree(const struct object_id *oid,
-		     const char *buffer, unsigned long size,
-		     struct fsck_options *options)
+static int fsck_tree(struct tree *item, struct fsck_options *options)
 {
 	int retval = 0;
 	int has_null_sha1 = 0;
@@ -588,8 +560,8 @@ static int fsck_tree(const struct object_id *oid,
 	unsigned o_mode;
 	const char *o_name;
 
-	if (init_tree_desc_gently(&desc, buffer, size)) {
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+	if (init_tree_desc_gently(&desc, item->buffer, item->size)) {
+		retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 		return retval;
 	}
 
@@ -598,7 +570,7 @@ static int fsck_tree(const struct object_id *oid,
 
 	while (desc.size) {
 		unsigned short mode;
-		const char *name, *backslash;
+		const char *name;
 		const struct object_id *oid;
 
 		oid = tree_entry_extract(&desc, &name, &mode);
@@ -615,30 +587,13 @@ static int fsck_tree(const struct object_id *oid,
 			if (!S_ISLNK(mode))
 				oidset_insert(&gitmodules_found, oid);
 			else
-				retval += report(options,
-						 oid, OBJ_TREE,
+				retval += report(options, &item->object,
 						 FSCK_MSG_GITMODULES_SYMLINK,
 						 ".gitmodules is a symbolic link");
 		}
 
-		if ((backslash = strchr(name, '\\'))) {
-			while (backslash) {
-				backslash++;
-				has_dotgit |= is_ntfs_dotgit(backslash);
-				if (is_ntfs_dotgitmodules(backslash)) {
-					if (!S_ISLNK(mode))
-						oidset_insert(&gitmodules_found, oid);
-					else
-						retval += report(options, oid, OBJ_TREE,
-								 FSCK_MSG_GITMODULES_SYMLINK,
-								 ".gitmodules is a symbolic link");
-				}
-				backslash = strchr(backslash, '\\');
-			}
-		}
-
 		if (update_tree_entry_gently(&desc)) {
-			retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+			retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
 			break;
 		}
 
@@ -683,31 +638,30 @@ static int fsck_tree(const struct object_id *oid,
 	}
 
 	if (has_null_sha1)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
+		retval += report(options, &item->object, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
 	if (has_full_path)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
+		retval += report(options, &item->object, FSCK_MSG_FULL_PATHNAME, "contains full pathnames");
 	if (has_empty_name)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
+		retval += report(options, &item->object, FSCK_MSG_EMPTY_NAME, "contains empty pathname");
 	if (has_dot)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_HAS_DOT, "contains '.'");
+		retval += report(options, &item->object, FSCK_MSG_HAS_DOT, "contains '.'");
 	if (has_dotdot)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_HAS_DOTDOT, "contains '..'");
+		retval += report(options, &item->object, FSCK_MSG_HAS_DOTDOT, "contains '..'");
 	if (has_dotgit)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
+		retval += report(options, &item->object, FSCK_MSG_HAS_DOTGIT, "contains '.git'");
 	if (has_zero_pad)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
+		retval += report(options, &item->object, FSCK_MSG_ZERO_PADDED_FILEMODE, "contains zero-padded file modes");
 	if (has_bad_modes)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
+		retval += report(options, &item->object, FSCK_MSG_BAD_FILEMODE, "contains bad file modes");
 	if (has_dup_entries)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
+		retval += report(options, &item->object, FSCK_MSG_DUPLICATE_ENTRIES, "contains duplicate file entries");
 	if (not_properly_sorted)
-		retval += report(options, oid, OBJ_TREE, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
+		retval += report(options, &item->object, FSCK_MSG_TREE_NOT_SORTED, "not properly sorted");
 	return retval;
 }
 
 static int verify_headers(const void *data, unsigned long size,
-			  const struct object_id *oid, enum object_type type,
-			  struct fsck_options *options)
+			  struct object *obj, struct fsck_options *options)
 {
 	const char *buffer = (const char *)data;
 	unsigned long i;
@@ -715,7 +669,7 @@ static int verify_headers(const void *data, unsigned long size,
 	for (i = 0; i < size; i++) {
 		switch (buffer[i]) {
 		case '\0':
-			return report(options, oid, type,
+			return report(options, obj,
 				FSCK_MSG_NUL_IN_HEADER,
 				"unterminated header: NUL at offset %ld", i);
 		case '\n':
@@ -733,13 +687,11 @@ static int verify_headers(const void *data, unsigned long size,
 	if (size && buffer[size - 1] == '\n')
 		return 0;
 
-	return report(options, oid, type,
+	return report(options, obj,
 		FSCK_MSG_UNTERMINATED_HEADER, "unterminated header");
 }
 
-static int fsck_ident(const char **ident,
-		      const struct object_id *oid, enum object_type type,
-		      struct fsck_options *options)
+static int fsck_ident(const char **ident, struct object *obj, struct fsck_options *options)
 {
 	const char *p = *ident;
 	char *end;
@@ -749,28 +701,28 @@ static int fsck_ident(const char **ident,
 		(*ident)++;
 
 	if (*p == '<')
-		return report(options, oid, type, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
+		return report(options, obj, FSCK_MSG_MISSING_NAME_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 	p += strcspn(p, "<>\n");
 	if (*p == '>')
-		return report(options, oid, type, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
+		return report(options, obj, FSCK_MSG_BAD_NAME, "invalid author/committer line - bad name");
 	if (*p != '<')
-		return report(options, oid, type, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
+		return report(options, obj, FSCK_MSG_MISSING_EMAIL, "invalid author/committer line - missing email");
 	if (p[-1] != ' ')
-		return report(options, oid, type, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
+		return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_EMAIL, "invalid author/committer line - missing space before email");
 	p++;
 	p += strcspn(p, "<>\n");
 	if (*p != '>')
-		return report(options, oid, type, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
+		return report(options, obj, FSCK_MSG_BAD_EMAIL, "invalid author/committer line - bad email");
 	p++;
 	if (*p != ' ')
-		return report(options, oid, type, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
+		return report(options, obj, FSCK_MSG_MISSING_SPACE_BEFORE_DATE, "invalid author/committer line - missing space before date");
 	p++;
 	if (*p == '0' && p[1] != ' ')
-		return report(options, oid, type, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
+		return report(options, obj, FSCK_MSG_ZERO_PADDED_DATE, "invalid author/committer line - zero-padded date");
 	if (date_overflows(parse_timestamp(p, &end, 10)))
-		return report(options, oid, type, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
+		return report(options, obj, FSCK_MSG_BAD_DATE_OVERFLOW, "invalid author/committer line - date causes integer overflow");
 	if ((end == p || *end != ' '))
-		return report(options, oid, type, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
+		return report(options, obj, FSCK_MSG_BAD_DATE, "invalid author/committer line - bad date");
 	p = end + 1;
 	if ((*p != '+' && *p != '-') ||
 	    !isdigit(p[1]) ||
@@ -778,60 +730,83 @@ static int fsck_ident(const char **ident,
 	    !isdigit(p[3]) ||
 	    !isdigit(p[4]) ||
 	    (p[5] != '\n'))
-		return report(options, oid, type, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
+		return report(options, obj, FSCK_MSG_BAD_TIMEZONE, "invalid author/committer line - bad time zone");
 	p += 6;
 	return 0;
 }
 
-static int fsck_commit(const struct object_id *oid,
-		       const char *buffer, unsigned long size,
-		       struct fsck_options *options)
+static int fsck_commit_buffer(struct commit *commit, const char *buffer,
+	unsigned long size, struct fsck_options *options)
 {
-	struct object_id tree_oid, parent_oid;
-	unsigned author_count;
+	struct object_id tree_oid, oid;
+	struct commit_graft *graft;
+	unsigned parent_count, parent_line_count = 0, author_count;
 	int err;
 	const char *buffer_begin = buffer;
 	const char *p;
 
-	if (verify_headers(buffer, size, oid, OBJ_COMMIT, options))
+	if (verify_headers(buffer, size, &commit->object, options))
 		return -1;
 
 	if (!skip_prefix(buffer, "tree ", &buffer))
-		return report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
+		return report(options, &commit->object, FSCK_MSG_MISSING_TREE, "invalid format - expected 'tree' line");
 	if (parse_oid_hex(buffer, &tree_oid, &p) || *p != '\n') {
-		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_BAD_TREE_SHA1, "invalid 'tree' line format - bad sha1");
+		err = report(options, &commit->object, 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, &parent_oid, &p) || *p != '\n') {
-			err = report(options, oid, OBJ_COMMIT, FSCK_MSG_BAD_PARENT_SHA1, "invalid 'parent' line format - bad sha1");
+		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");
 			if (err)
 				return err;
 		}
 		buffer = p + 1;
+		parent_line_count++;
+	}
+	graft = lookup_commit_graft(the_repository, &commit->object.oid);
+	parent_count = commit_list_count(commit->parents);
+	if (graft) {
+		if (graft->nr_parent == -1 && !parent_count)
+			; /* shallow commit */
+		else if (graft->nr_parent != parent_count) {
+			err = report(options, &commit->object, FSCK_MSG_MISSING_GRAFT, "graft objects missing");
+			if (err)
+				return err;
+		}
+	} else {
+		if (parent_count != parent_line_count) {
+			err = report(options, &commit->object, FSCK_MSG_MISSING_PARENT, "parent objects missing");
+			if (err)
+				return err;
+		}
 	}
 	author_count = 0;
 	while (skip_prefix(buffer, "author ", &buffer)) {
 		author_count++;
-		err = fsck_ident(&buffer, oid, OBJ_COMMIT, options);
+		err = fsck_ident(&buffer, &commit->object, options);
 		if (err)
 			return err;
 	}
 	if (author_count < 1)
-		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
+		err = report(options, &commit->object, FSCK_MSG_MISSING_AUTHOR, "invalid format - expected 'author' line");
 	else if (author_count > 1)
-		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
+		err = report(options, &commit->object, FSCK_MSG_MULTIPLE_AUTHORS, "invalid format - multiple 'author' lines");
 	if (err)
 		return err;
 	if (!skip_prefix(buffer, "committer ", &buffer))
-		return report(options, oid, OBJ_COMMIT, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
-	err = fsck_ident(&buffer, oid, OBJ_COMMIT, options);
+		return report(options, &commit->object, FSCK_MSG_MISSING_COMMITTER, "invalid format - expected 'committer' line");
+	err = fsck_ident(&buffer, &commit->object, options);
 	if (err)
 		return err;
+	if (!get_commit_tree(commit)) {
+		err = report(options, &commit->object, FSCK_MSG_BAD_TREE, "could not load commit's tree %s", oid_to_hex(&tree_oid));
+		if (err)
+			return err;
+	}
 	if (memchr(buffer_begin, '\0', size)) {
-		err = report(options, oid, OBJ_COMMIT, FSCK_MSG_NUL_IN_COMMIT,
+		err = report(options, &commit->object, FSCK_MSG_NUL_IN_COMMIT,
 			     "NUL byte in the commit object body");
 		if (err)
 			return err;
@@ -839,60 +814,91 @@ static int fsck_commit(const struct object_id *oid,
 	return 0;
 }
 
-static int fsck_tag(const struct object_id *oid, const char *buffer,
-		    unsigned long size, struct fsck_options *options)
+static int fsck_commit(struct commit *commit, const char *data,
+	unsigned long size, struct fsck_options *options)
 {
-	struct object_id tagged_oid;
+	const char *buffer = data ?  data : get_commit_buffer(commit, &size);
+	int ret = fsck_commit_buffer(commit, buffer, size, options);
+	if (!data)
+		unuse_commit_buffer(commit, buffer);
+	return ret;
+}
+
+static int fsck_tag_buffer(struct tag *tag, const char *data,
+	unsigned long size, struct fsck_options *options)
+{
+	struct object_id oid;
 	int ret = 0;
-	char *eol;
+	const char *buffer;
+	char *to_free = NULL, *eol;
 	struct strbuf sb = STRBUF_INIT;
 	const char *p;
 
-	ret = verify_headers(buffer, size, oid, OBJ_TAG, options);
+	if (data)
+		buffer = data;
+	else {
+		enum object_type type;
+
+		buffer = to_free =
+			read_object_file(&tag->object.oid, &type, &size);
+		if (!buffer)
+			return report(options, &tag->object,
+				FSCK_MSG_MISSING_TAG_OBJECT,
+				"cannot read tag object");
+
+		if (type != OBJ_TAG) {
+			ret = report(options, &tag->object,
+				FSCK_MSG_TAG_OBJECT_NOT_TAG,
+				"expected tag got %s",
+			    type_name(type));
+			goto done;
+		}
+	}
+
+	ret = verify_headers(buffer, size, &tag->object, options);
 	if (ret)
 		goto done;
 
 	if (!skip_prefix(buffer, "object ", &buffer)) {
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
+		ret = report(options, &tag->object, FSCK_MSG_MISSING_OBJECT, "invalid format - expected 'object' line");
 		goto done;
 	}
-	if (parse_oid_hex(buffer, &tagged_oid, &p) || *p != '\n') {
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_BAD_OBJECT_SHA1, "invalid 'object' line format - bad sha1");
+	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");
 		if (ret)
 			goto done;
 	}
 	buffer = p + 1;
 
 	if (!skip_prefix(buffer, "type ", &buffer)) {
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
+		ret = report(options, &tag->object, FSCK_MSG_MISSING_TYPE_ENTRY, "invalid format - expected 'type' line");
 		goto done;
 	}
 	eol = strchr(buffer, '\n');
 	if (!eol) {
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TYPE, "invalid format - unexpected end after 'type' line");
+		ret = report(options, &tag->object, 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, oid, OBJ_TAG, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
+		ret = report(options, &tag->object, FSCK_MSG_BAD_TYPE, "invalid 'type' value");
 	if (ret)
 		goto done;
 	buffer = eol + 1;
 
 	if (!skip_prefix(buffer, "tag ", &buffer)) {
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
+		ret = report(options, &tag->object, FSCK_MSG_MISSING_TAG_ENTRY, "invalid format - expected 'tag' line");
 		goto done;
 	}
 	eol = strchr(buffer, '\n');
 	if (!eol) {
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAG, "invalid format - unexpected end after 'type' line");
+		ret = report(options, &tag->object, 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, oid, OBJ_TAG,
-			     FSCK_MSG_BAD_TAG_NAME,
-			     "invalid 'tag' name: %.*s",
-			     (int)(eol - buffer), buffer);
+		ret = report(options, &tag->object, FSCK_MSG_BAD_TAG_NAME,
+			   "invalid 'tag' name: %.*s",
+			   (int)(eol - buffer), buffer);
 		if (ret)
 			goto done;
 	}
@@ -900,163 +906,32 @@ static int fsck_tag(const struct object_id *oid, const char *buffer,
 
 	if (!skip_prefix(buffer, "tagger ", &buffer)) {
 		/* early tags do not contain 'tagger' lines; warn only */
-		ret = report(options, oid, OBJ_TAG, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
+		ret = report(options, &tag->object, FSCK_MSG_MISSING_TAGGER_ENTRY, "invalid format - expected 'tagger' line");
 		if (ret)
 			goto done;
 	}
 	else
-		ret = fsck_ident(&buffer, oid, OBJ_TAG, options);
+		ret = fsck_ident(&buffer, &tag->object, options);
 
 done:
 	strbuf_release(&sb);
+	free(to_free);
 	return ret;
 }
 
-/*
- * Like builtin/submodule--helper.c's starts_with_dot_slash, but without
- * relying on the platform-dependent is_dir_sep helper.
- *
- * This is for use in checking whether a submodule URL is interpreted as
- * relative to the current directory on any platform, since \ is a
- * directory separator on Windows but not on other platforms.
- */
-static int starts_with_dot_slash(const char *str)
-{
-	return str[0] == '.' && (str[1] == '/' || str[1] == '\\');
-}
-
-/*
- * Like starts_with_dot_slash, this is a variant of submodule--helper's
- * helper of the same name with the twist that it accepts backslash as a
- * directory separator even on non-Windows platforms.
- */
-static int starts_with_dot_dot_slash(const char *str)
-{
-	return str[0] == '.' && starts_with_dot_slash(str + 1);
-}
-
-static int submodule_url_is_relative(const char *url)
-{
-	return starts_with_dot_slash(url) || starts_with_dot_dot_slash(url);
-}
-
-/*
- * Count directory components that a relative submodule URL should chop
- * from the remote_url it is to be resolved against.
- *
- * In other words, this counts "../" components at the start of a
- * submodule URL.
- *
- * Returns the number of directory components to chop and writes a
- * pointer to the next character of url after all leading "./" and
- * "../" components to out.
- */
-static int count_leading_dotdots(const char *url, const char **out)
-{
-	int result = 0;
-	while (1) {
-		if (starts_with_dot_dot_slash(url)) {
-			result++;
-			url += strlen("../");
-			continue;
-		}
-		if (starts_with_dot_slash(url)) {
-			url += strlen("./");
-			continue;
-		}
-		*out = url;
-		return result;
-	}
-}
-/*
- * Check whether a transport is implemented by git-remote-curl.
- *
- * If it is, returns 1 and writes the URL that would be passed to
- * git-remote-curl to the "out" parameter.
- *
- * Otherwise, returns 0 and leaves "out" untouched.
- *
- * Examples:
- *   http::https://example.com/repo.git -> 1, https://example.com/repo.git
- *   https://example.com/repo.git -> 1, https://example.com/repo.git
- *   git://example.com/repo.git -> 0
- *
- * This is for use in checking for previously exploitable bugs that
- * required a submodule URL to be passed to git-remote-curl.
- */
-static int url_to_curl_url(const char *url, const char **out)
+static int fsck_tag(struct tag *tag, const char *data,
+	unsigned long size, struct fsck_options *options)
 {
-	/*
-	 * We don't need to check for case-aliases, "http.exe", and so
-	 * on because in the default configuration, is_transport_allowed
-	 * prevents URLs with those schemes from being cloned
-	 * automatically.
-	 */
-	if (skip_prefix(url, "http::", out) ||
-	    skip_prefix(url, "https::", out) ||
-	    skip_prefix(url, "ftp::", out) ||
-	    skip_prefix(url, "ftps::", out))
-		return 1;
-	if (starts_with(url, "http://") ||
-	    starts_with(url, "https://") ||
-	    starts_with(url, "ftp://") ||
-	    starts_with(url, "ftps://")) {
-		*out = url;
-		return 1;
-	}
-	return 0;
-}
+	struct object *tagged = tag->tagged;
 
-static int check_submodule_url(const char *url)
-{
-	const char *curl_url;
-
-	if (looks_like_command_line_option(url))
-		return -1;
-
-	if (submodule_url_is_relative(url)) {
-		char *decoded;
-		const char *next;
-		int has_nl;
-
-		/*
-		 * This could be appended to an http URL and url-decoded;
-		 * check for malicious characters.
-		 */
-		decoded = url_decode(url);
-		has_nl = !!strchr(decoded, '\n');
-
-		free(decoded);
-		if (has_nl)
-			return -1;
-
-		/*
-		 * URLs which escape their root via "../" can overwrite
-		 * the host field and previous components, resolving to
-		 * URLs like https::example.com/submodule.git and
-		 * https:///example.com/submodule.git that were
-		 * susceptible to CVE-2020-11008.
-		 */
-		if (count_leading_dotdots(url, &next) > 0 &&
-		    (*next == ':' || *next == '/'))
-			return -1;
-	}
+	if (!tagged)
+		return report(options, &tag->object, FSCK_MSG_BAD_TAG_OBJECT, "could not load tagged object");
 
-	else if (url_to_curl_url(url, &curl_url)) {
-		struct credential c = CREDENTIAL_INIT;
-		int ret = 0;
-		if (credential_from_url_gently(&c, curl_url, 1) ||
-		    !*c.host)
-			ret = -1;
-		credential_clear(&c);
-		return ret;
-	}
-
-	return 0;
+	return fsck_tag_buffer(tag, data, size, options);
 }
 
 struct fsck_gitmodules_data {
-	const struct object_id *oid;
+	struct object *obj;
 	struct fsck_options *options;
 	int ret;
 };
@@ -1074,47 +949,38 @@ 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->oid, OBJ_BLOB,
+		data->ret |= report(data->options, data->obj,
 				    FSCK_MSG_GITMODULES_NAME,
 				    "disallowed submodule name: %s",
 				    name);
 	if (!strcmp(key, "url") && value &&
-	    check_submodule_url(value) < 0)
-		data->ret |= report(data->options,
-				    data->oid, OBJ_BLOB,
+	    looks_like_command_line_option(value))
+		data->ret |= report(data->options, data->obj,
 				    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->oid, OBJ_BLOB,
+		data->ret |= report(data->options, data->obj,
 				    FSCK_MSG_GITMODULES_PATH,
 				    "disallowed submodule path: %s",
 				    value);
-	if (!strcmp(key, "update") && value &&
-	    parse_submodule_update_type(value) == SM_UPDATE_COMMAND)
-		data->ret |= report(data->options, data->oid, OBJ_BLOB,
-				    FSCK_MSG_GITMODULES_UPDATE,
-				    "disallowed submodule update setting: %s",
-				    value);
 	free(name);
 
 	return 0;
 }
 
-static int fsck_blob(const struct object_id *oid, const char *buf,
+static int fsck_blob(struct blob *blob, const char *buf,
 		     unsigned long size, struct fsck_options *options)
 {
 	struct fsck_gitmodules_data data;
 	struct config_options config_opts = { 0 };
 
-	if (!oidset_contains(&gitmodules_found, oid))
+	if (!oidset_contains(&gitmodules_found, &blob->object.oid))
 		return 0;
-	oidset_insert(&gitmodules_done, oid);
+	oidset_insert(&gitmodules_done, &blob->object.oid);
 
-	if (object_on_skiplist(options, oid))
+	if (object_on_skiplist(options, &blob->object))
 		return 0;
 
 	if (!buf) {
@@ -1123,18 +989,18 @@ static int fsck_blob(const struct object_id *oid, const char *buf,
 		 * blob too gigantic to load into memory. Let's just consider
 		 * that an error.
 		 */
-		return report(options, oid, OBJ_BLOB,
+		return report(options, &blob->object,
 			      FSCK_MSG_GITMODULES_LARGE,
 			      ".gitmodules too large to parse");
 	}
 
-	data.oid = oid;
+	data.obj = &blob->object;
 	data.options = options;
 	data.ret = 0;
 	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, oid, OBJ_BLOB,
+		data.ret |= report(options, &blob->object,
 				   FSCK_MSG_GITMODULES_PARSE,
 				   "could not parse gitmodules blob");
 
@@ -1145,33 +1011,31 @@ int fsck_object(struct object *obj, void *data, unsigned long size,
 	struct fsck_options *options)
 {
 	if (!obj)
-		return report(options, NULL, OBJ_NONE, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
+		return report(options, obj, FSCK_MSG_BAD_OBJECT_SHA1, "no valid object to fsck");
 
 	if (obj->type == OBJ_BLOB)
-		return fsck_blob(&obj->oid, data, size, options);
+		return fsck_blob((struct blob *)obj, data, size, options);
 	if (obj->type == OBJ_TREE)
-		return fsck_tree(&obj->oid, data, size, options);
+		return fsck_tree((struct tree *) obj, options);
 	if (obj->type == OBJ_COMMIT)
-		return fsck_commit(&obj->oid, data, size, options);
+		return fsck_commit((struct commit *) obj, (const char *) data,
+			size, options);
 	if (obj->type == OBJ_TAG)
-		return fsck_tag(&obj->oid, data, size, options);
+		return fsck_tag((struct tag *) obj, (const char *) data,
+			size, options);
 
-	return report(options, &obj->oid, obj->type,
-		      FSCK_MSG_UNKNOWN_TYPE,
-		      "unknown type '%d' (internal fsck error)",
-		      obj->type);
+	return report(options, obj, FSCK_MSG_UNKNOWN_TYPE, "unknown type '%d' (internal fsck error)",
+			  obj->type);
 }
 
 int fsck_error_function(struct fsck_options *o,
-			const struct object_id *oid,
-			enum object_type object_type,
-			int msg_type, const char *message)
+	struct object *obj, int msg_type, const char *message)
 {
 	if (msg_type == FSCK_WARN) {
-		warning("object %s: %s", fsck_describe_object(o, oid), message);
+		warning("object %s: %s", describe_object(o, obj), message);
 		return 0;
 	}
-	error("object %s: %s", fsck_describe_object(o, oid), message);
+	error("object %s: %s", describe_object(o, obj), message);
 	return 1;
 }
 
@@ -1183,6 +1047,7 @@ int fsck_finish(struct fsck_options *options)
 
 	oidset_iter_init(&gitmodules_found, &iter);
 	while ((oid = oidset_iter_next(&iter))) {
+		struct blob *blob;
 		enum object_type type;
 		unsigned long size;
 		char *buf;
@@ -1190,22 +1055,29 @@ int fsck_finish(struct fsck_options *options)
 		if (oidset_contains(&gitmodules_done, oid))
 			continue;
 
+		blob = lookup_blob(the_repository, oid);
+		if (!blob) {
+			struct object *obj = lookup_unknown_object(oid);
+			ret |= report(options, obj,
+				      FSCK_MSG_GITMODULES_BLOB,
+				      "non-blob found at .gitmodules");
+			continue;
+		}
+
 		buf = read_object_file(oid, &type, &size);
 		if (!buf) {
-			if (is_promisor_object(oid))
+			if (is_promisor_object(&blob->object.oid))
 				continue;
-			ret |= report(options,
-				      oid, OBJ_BLOB,
+			ret |= report(options, &blob->object,
 				      FSCK_MSG_GITMODULES_MISSING,
 				      "unable to read .gitmodules blob");
 			continue;
 		}
 
 		if (type == OBJ_BLOB)
-			ret |= fsck_blob(oid, buf, size, options);
+			ret |= fsck_blob(blob, buf, size, options);
 		else
-			ret |= report(options,
-				      oid, type,
+			ret |= report(options, &blob->object,
 				      FSCK_MSG_GITMODULES_BLOB,
 				      "non-blob found at .gitmodules");
 		free(buf);