X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=fsck.c;h=797e3178ae279f444d2efa7e3758652ad0898dd7;hb=fae09a8084c9b51632726523b477a78dd28d7d7e;hp=558f0a6b349b921802668282e8c2b71b0f03d754;hpb=df391b192d285646fe80ca4d3cfe3c0a3beb5989;p=git.git

diff --git a/fsck.c b/fsck.c
index 558f0a6b3..797e3178a 100644
--- a/fsck.c
+++ b/fsck.c
@@ -1,164 +1,92 @@
 #include "cache.h"
-#include "commit.h"
-#include "tree.h"
+#include "object.h"
 #include "blob.h"
-#include "tag.h"
-#include "refs.h"
-#include "pack.h"
-#include "cache-tree.h"
+#include "tree.h"
 #include "tree-walk.h"
+#include "commit.h"
+#include "tag.h"
+#include "fsck.h"
 
-#define REACHABLE 0x0001
-#define SEEN      0x0002
-
-static int show_root;
-static int show_tags;
-static int show_unreachable;
-static int check_full;
-static int check_strict;
-static int keep_cache_objects;
-static unsigned char head_sha1[20];
-
-#ifdef NO_D_INO_IN_DIRENT
-#define SORT_DIRENT 0
-#define DIRENT_SORT_HINT(de) 0
-#else
-#define SORT_DIRENT 1
-#define DIRENT_SORT_HINT(de) ((de)->d_ino)
-#endif
-
-static void objreport(struct object *obj, const char *severity,
-                      const char *err, va_list params)
-{
-	fprintf(stderr, "%s in %s %s: ",
-	        severity, typename(obj->type), sha1_to_hex(obj->sha1));
-	vfprintf(stderr, err, params);
-	fputs("\n", stderr);
-}
-
-static int objerror(struct object *obj, const char *err, ...)
-{
-	va_list params;
-	va_start(params, err);
-	objreport(obj, "error", err, params);
-	va_end(params);
-	return -1;
-}
-
-static int objwarning(struct object *obj, const char *err, ...)
+static int fsck_walk_tree(struct tree *tree, fsck_walk_func walk, void *data)
 {
-	va_list params;
-	va_start(params, err);
-	objreport(obj, "warning", err, params);
-	va_end(params);
-	return -1;
-}
+	struct tree_desc desc;
+	struct name_entry entry;
+	int res = 0;
 
-/*
- * Check a single reachable object
- */
-static void check_reachable_object(struct object *obj)
-{
-	const struct object_refs *refs;
+	if (parse_tree(tree))
+		return -1;
 
-	/*
-	 * We obviously want the object to be parsed,
-	 * except if it was in a pack-file and we didn't
-	 * do a full fsck
-	 */
-	if (!obj->parsed) {
-		if (has_sha1_file(obj->sha1))
-			return; /* it is in pack - forget about it */
-		printf("missing %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
-		return;
-	}
+	init_tree_desc(&desc, tree->buffer, tree->size);
+	while (tree_entry(&desc, &entry)) {
+		int result;
 
-	/*
-	 * Check that everything that we try to reference is also good.
-	 */
-	refs = lookup_object_refs(obj);
-	if (refs) {
-		unsigned j;
-		for (j = 0; j < refs->count; j++) {
-			struct object *ref = refs->ref[j];
-			if (ref->parsed ||
-			    (has_sha1_file(ref->sha1)))
-				continue;
-			printf("broken link from %7s %s\n",
-			       typename(obj->type), sha1_to_hex(obj->sha1));
-			printf("              to %7s %s\n",
-			       typename(ref->type), sha1_to_hex(ref->sha1));
+		if (S_ISGITLINK(entry.mode))
+			continue;
+		if (S_ISDIR(entry.mode))
+			result = walk(&lookup_tree(entry.sha1)->object, OBJ_TREE, data);
+		else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
+			result = walk(&lookup_blob(entry.sha1)->object, OBJ_BLOB, data);
+		else {
+			result = error("in tree %s: entry %s has bad mode %.6o\n",
+					sha1_to_hex(tree->object.sha1), entry.path, entry.mode);
 		}
+		if (result < 0)
+			return result;
+		if (!res)
+			res = result;
 	}
+	return res;
 }
 
-/*
- * Check a single unreachable object
- */
-static void check_unreachable_object(struct object *obj)
+static int fsck_walk_commit(struct commit *commit, fsck_walk_func walk, void *data)
 {
-	/*
-	 * Missing unreachable object? Ignore it. It's not like
-	 * we miss it (since it can't be reached), nor do we want
-	 * to complain about it being unreachable (since it does
-	 * not exist).
-	 */
-	if (!obj->parsed)
-		return;
-
-	/*
-	 * Unreachable object that exists? Show it if asked to,
-	 * since this is something that is prunable.
-	 */
-	if (show_unreachable) {
-		printf("unreachable %s %s\n", typename(obj->type), sha1_to_hex(obj->sha1));
-		return;
-	}
-
-	/*
-	 * "!used" means that nothing at all points to it, including
-	 * other unreacahble objects. In other words, it's the "tip"
-	 * of some set of unreachable objects, usually a commit that
-	 * got dropped.
-	 *
-	 * Such starting points are more interesting than some random
-	 * set of unreachable objects, so we show them even if the user
-	 * hasn't asked for _all_ unreachable objects. If you have
-	 * deleted a branch by mistake, this is a prime candidate to
-	 * start looking at, for example.
-	 */
-	if (!obj->used) {
-		printf("dangling %s %s\n", typename(obj->type),
-		       sha1_to_hex(obj->sha1));
-		return;
+	struct commit_list *parents;
+	int res;
+	int result;
+
+	if (parse_commit(commit))
+		return -1;
+
+	result = walk((struct object *)commit->tree, OBJ_TREE, data);
+	if (result < 0)
+		return result;
+	res = result;
+
+	parents = commit->parents;
+	while (parents) {
+		result = walk((struct object *)parents->item, OBJ_COMMIT, data);
+		if (result < 0)
+			return result;
+		if (!res)
+			res = result;
+		parents = parents->next;
 	}
-
-	/*
-	 * Otherwise? It's there, it's unreachable, and some other unreachable
-	 * object points to it. Ignore it - it's not interesting, and we showed
-	 * all the interesting cases above.
-	 */
+	return res;
 }
 
-static void check_object(struct object *obj)
+static int fsck_walk_tag(struct tag *tag, fsck_walk_func walk, void *data)
 {
-	if (obj->flags & REACHABLE)
-		check_reachable_object(obj);
-	else
-		check_unreachable_object(obj);
+	if (parse_tag(tag))
+		return -1;
+	return walk(tag->tagged, OBJ_ANY, data);
 }
 
-static void check_connectivity(void)
+int fsck_walk(struct object *obj, fsck_walk_func walk, void *data)
 {
-	int i, max;
-
-	/* Look up all the requirements, warn about missing objects.. */
-	max = get_max_object_index();
-	for (i = 0; i < max; i++) {
-		struct object *obj = get_indexed_object(i);
-
-		if (obj)
-			check_object(obj);
+	if (!obj)
+		return -1;
+	switch (obj->type) {
+	case OBJ_BLOB:
+		return 0;
+	case OBJ_TREE:
+		return fsck_walk_tree((struct tree *)obj, walk, data);
+	case OBJ_COMMIT:
+		return fsck_walk_commit((struct commit *)obj, walk, data);
+	case OBJ_TAG:
+		return fsck_walk_tag((struct tag *)obj, walk, data);
+	default:
+		error("Unknown object type for %s", sha1_to_hex(obj->sha1));
+		return -1;
 	}
 }
 
@@ -208,10 +136,11 @@ static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, con
 	return c1 < c2 ? 0 : TREE_UNORDERED;
 }
 
-static int fsck_tree(struct tree *item)
+static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
 {
 	int retval;
 	int has_full_path = 0;
+	int has_empty_name = 0;
 	int has_zero_pad = 0;
 	int has_bad_modes = 0;
 	int has_dup_entries = 0;
@@ -221,12 +150,12 @@ static int fsck_tree(struct tree *item)
 	const char *o_name;
 	const unsigned char *o_sha1;
 
-	desc.buf = item->buffer;
-	desc.size = item->size;
+	init_tree_desc(&desc, item->buffer, item->size);
 
 	o_mode = 0;
 	o_name = NULL;
 	o_sha1 = NULL;
+
 	while (desc.size) {
 		unsigned mode;
 		const char *name;
@@ -236,7 +165,9 @@ static int fsck_tree(struct tree *item)
 
 		if (strchr(name, '/'))
 			has_full_path = 1;
-		has_zero_pad |= *(char *)desc.buf == '0';
+		if (!*name)
+			has_empty_name = 1;
+		has_zero_pad |= *(char *)desc.buffer == '0';
 		update_tree_entry(&desc);
 
 		switch (mode) {
@@ -247,6 +178,7 @@ static int fsck_tree(struct tree *item)
 		case S_IFREG | 0644:
 		case S_IFLNK:
 		case S_IFDIR:
+		case S_IFGITLINK:
 			break;
 		/*
 		 * This is nonstandard, but we had a few of these
@@ -254,7 +186,7 @@ static int fsck_tree(struct tree *item)
 		 * bits..
 		 */
 		case S_IFREG | 0664:
-			if (!check_strict)
+			if (!strict)
 				break;
 		default:
 			has_bad_modes = 1;
@@ -277,414 +209,125 @@ static int fsck_tree(struct tree *item)
 		o_name = name;
 		o_sha1 = sha1;
 	}
-	free(item->buffer);
-	item->buffer = NULL;
 
 	retval = 0;
-	if (has_full_path) {
-		objwarning(&item->object, "contains full pathnames");
-	}
-	if (has_zero_pad) {
-		objwarning(&item->object, "contains zero-padded file modes");
-	}
-	if (has_bad_modes) {
-		objwarning(&item->object, "contains bad file modes");
-	}
-	if (has_dup_entries) {
-		retval = objerror(&item->object, "contains duplicate file entries");
-	}
-	if (not_properly_sorted) {
-		retval = objerror(&item->object, "not properly sorted");
-	}
+	if (has_full_path)
+		retval += error_func(&item->object, FSCK_WARN, "contains full pathnames");
+	if (has_empty_name)
+		retval += error_func(&item->object, FSCK_WARN, "contains empty pathname");
+	if (has_zero_pad)
+		retval += error_func(&item->object, FSCK_WARN, "contains zero-padded file modes");
+	if (has_bad_modes)
+		retval += error_func(&item->object, FSCK_WARN, "contains bad file modes");
+	if (has_dup_entries)
+		retval += error_func(&item->object, FSCK_ERROR, "contains duplicate file entries");
+	if (not_properly_sorted)
+		retval += error_func(&item->object, FSCK_ERROR, "not properly sorted");
 	return retval;
 }
 
-static int fsck_commit(struct commit *commit)
+static int fsck_commit(struct commit *commit, fsck_error error_func)
 {
 	char *buffer = commit->buffer;
 	unsigned char tree_sha1[20], sha1[20];
+	struct commit_graft *graft;
+	int parents = 0;
+
+	if (!commit->date)
+		return error_func(&commit->object, FSCK_ERROR, "invalid author/committer line");
 
 	if (memcmp(buffer, "tree ", 5))
-		return objerror(&commit->object, "invalid format - expected 'tree' line");
+		return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
 	if (get_sha1_hex(buffer+5, tree_sha1) || buffer[45] != '\n')
-		return objerror(&commit->object, "invalid 'tree' line format - bad sha1");
+		return error_func(&commit->object, FSCK_ERROR, "invalid 'tree' line format - bad sha1");
 	buffer += 46;
 	while (!memcmp(buffer, "parent ", 7)) {
 		if (get_sha1_hex(buffer+7, sha1) || buffer[47] != '\n')
-			return objerror(&commit->object, "invalid 'parent' line format - bad sha1");
+			return error_func(&commit->object, FSCK_ERROR, "invalid 'parent' line format - bad sha1");
 		buffer += 48;
+		parents++;
+	}
+	graft = lookup_commit_graft(commit->object.sha1);
+	if (graft) {
+		struct commit_list *p = commit->parents;
+		parents = 0;
+		while (p) {
+			p = p->next;
+			parents++;
+		}
+		if (graft->nr_parent == -1 && !parents)
+			; /* shallow commit */
+		else if (graft->nr_parent != parents)
+			return error_func(&commit->object, FSCK_ERROR, "graft objects missing");
+	} else {
+		struct commit_list *p = commit->parents;
+		while (p && parents) {
+			p = p->next;
+			parents--;
+		}
+		if (p || parents)
+			return error_func(&commit->object, FSCK_ERROR, "parent objects missing");
 	}
 	if (memcmp(buffer, "author ", 7))
-		return objerror(&commit->object, "invalid format - expected 'author' line");
-	free(commit->buffer);
-	commit->buffer = NULL;
+		return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'author' line");
 	if (!commit->tree)
-		return objerror(&commit->object, "could not load commit's tree %s", tree_sha1);
-	if (!commit->parents && show_root)
-		printf("root %s\n", sha1_to_hex(commit->object.sha1));
-	if (!commit->date)
-		printf("bad commit date in %s\n", 
-		       sha1_to_hex(commit->object.sha1));
+		return error_func(&commit->object, FSCK_ERROR, "could not load commit's tree %s", sha1_to_hex(tree_sha1));
+
 	return 0;
 }
 
-static int fsck_tag(struct tag *tag)
+static int fsck_tag(struct tag *tag, fsck_error error_func)
 {
 	struct object *tagged = tag->tagged;
 
-	if (!tagged) {
-		return objerror(&tag->object, "could not load tagged object");
-	}
-	if (!show_tags)
-		return 0;
-
-	printf("tagged %s %s", typename(tagged->type), sha1_to_hex(tagged->sha1));
-	printf(" (%s) in %s\n", tag->tag, sha1_to_hex(tag->object.sha1));
+	if (!tagged)
+		return error_func(&tag->object, FSCK_ERROR, "could not load tagged object");
 	return 0;
 }
 
-static int fsck_sha1(unsigned char *sha1)
+int fsck_object(struct object *obj, int strict, fsck_error error_func)
 {
-	struct object *obj = parse_object(sha1);
 	if (!obj)
-		return error("%s: object corrupt or missing", sha1_to_hex(sha1));
-	if (obj->flags & SEEN)
-		return 0;
-	obj->flags |= SEEN;
+		return error_func(obj, FSCK_ERROR, "no valid object to fsck");
+
 	if (obj->type == OBJ_BLOB)
 		return 0;
 	if (obj->type == OBJ_TREE)
-		return fsck_tree((struct tree *) obj);
+		return fsck_tree((struct tree *) obj, strict, error_func);
 	if (obj->type == OBJ_COMMIT)
-		return fsck_commit((struct commit *) obj);
+		return fsck_commit((struct commit *) obj, error_func);
 	if (obj->type == OBJ_TAG)
-		return fsck_tag((struct tag *) obj);
-	/* By now, parse_object() would've returned NULL instead. */
-	return objerror(obj, "unknown type '%d' (internal fsck error)", obj->type);
-}
+		return fsck_tag((struct tag *) obj, error_func);
 
-/*
- * This is the sorting chunk size: make it reasonably
- * big so that we can sort well..
- */
-#define MAX_SHA1_ENTRIES (1024)
-
-struct sha1_entry {
-	unsigned long ino;
-	unsigned char sha1[20];
-};
-
-static struct {
-	unsigned long nr;
-	struct sha1_entry *entry[MAX_SHA1_ENTRIES];
-} sha1_list;
-
-static int ino_compare(const void *_a, const void *_b)
-{
-	const struct sha1_entry *a = _a, *b = _b;
-	unsigned long ino1 = a->ino, ino2 = b->ino;
-	return ino1 < ino2 ? -1 : ino1 > ino2 ? 1 : 0;
-}
-
-static void fsck_sha1_list(void)
-{
-	int i, nr = sha1_list.nr;
-
-	if (SORT_DIRENT)
-		qsort(sha1_list.entry, nr,
-		      sizeof(struct sha1_entry *), ino_compare);
-	for (i = 0; i < nr; i++) {
-		struct sha1_entry *entry = sha1_list.entry[i];
-		unsigned char *sha1 = entry->sha1;
-
-		sha1_list.entry[i] = NULL;
-		fsck_sha1(sha1);
-		free(entry);
-	}
-	sha1_list.nr = 0;
+	return error_func(obj, FSCK_ERROR, "unknown type '%d' (internal fsck error)",
+			  obj->type);
 }
 
-static void add_sha1_list(unsigned char *sha1, unsigned long ino)
+int fsck_error_function(struct object *obj, int type, const char *fmt, ...)
 {
-	struct sha1_entry *entry = xmalloc(sizeof(*entry));
-	int nr;
-
-	entry->ino = ino;
-	hashcpy(entry->sha1, sha1);
-	nr = sha1_list.nr;
-	if (nr == MAX_SHA1_ENTRIES) {
-		fsck_sha1_list();
-		nr = 0;
+	va_list ap;
+	int len;
+	struct strbuf sb;
+
+	strbuf_init(&sb, 0);
+	strbuf_addf(&sb, "object %s:", obj->sha1?sha1_to_hex(obj->sha1):"(null)");
+
+	va_start(ap, fmt);
+	len = vsnprintf(sb.buf + sb.len, strbuf_avail(&sb), fmt, ap);
+	va_end(ap);
+
+	if (len < 0)
+		len = 0;
+	if (len >= strbuf_avail(&sb)) {
+		strbuf_grow(&sb, len + 2);
+		va_start(ap, fmt);
+		len = vsnprintf(sb.buf + sb.len, strbuf_avail(&sb), fmt, ap);
+		va_end(ap);
+		if (len >= strbuf_avail(&sb))
+			die("this should not happen, your snprintf is broken");
 	}
-	sha1_list.entry[nr] = entry;
-	sha1_list.nr = ++nr;
-}
-
-static void fsck_dir(int i, char *path)
-{
-	DIR *dir = opendir(path);
-	struct dirent *de;
-
-	if (!dir)
-		return;
-
-	while ((de = readdir(dir)) != NULL) {
-		char name[100];
-		unsigned char sha1[20];
-		int len = strlen(de->d_name);
 
-		switch (len) {
-		case 2:
-			if (de->d_name[1] != '.')
-				break;
-		case 1:
-			if (de->d_name[0] != '.')
-				break;
-			continue;
-		case 38:
-			sprintf(name, "%02x", i);
-			memcpy(name+2, de->d_name, len+1);
-			if (get_sha1_hex(name, sha1) < 0)
-				break;
-			add_sha1_list(sha1, DIRENT_SORT_HINT(de));
-			continue;
-		}
-		fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
-	}
-	closedir(dir);
-}
-
-static int default_refs;
-
-static int fsck_handle_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
-		const char *email, unsigned long timestamp, int tz,
-		const char *message, void *cb_data)
-{
-	struct object *obj;
-
-	if (!is_null_sha1(osha1)) {
-		obj = lookup_object(osha1);
-		if (obj) {
-			obj->used = 1;
-			mark_reachable(obj, REACHABLE);
-		}
-	}
-	obj = lookup_object(nsha1);
-	if (obj) {
-		obj->used = 1;
-		mark_reachable(obj, REACHABLE);
-	}
-	return 0;
-}
-
-static int fsck_handle_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
-{
-	struct object *obj;
-
-	obj = lookup_object(sha1);
-	if (!obj) {
-		if (has_sha1_file(sha1)) {
-			default_refs++;
-			return 0; /* it is in a pack */
-		}
-		error("%s: invalid sha1 pointer %s", refname, sha1_to_hex(sha1));
-		/* We'll continue with the rest despite the error.. */
-		return 0;
-	}
-	default_refs++;
-	obj->used = 1;
-	mark_reachable(obj, REACHABLE);
-
-	for_each_reflog_ent(refname, fsck_handle_reflog_ent, NULL);
-
-	return 0;
-}
-
-static void get_default_heads(void)
-{
-	for_each_ref(fsck_handle_ref, NULL);
-
-	/*
-	 * Not having any default heads isn't really fatal, but
-	 * it does mean that "--unreachable" no longer makes any
-	 * sense (since in this case everything will obviously
-	 * be unreachable by definition.
-	 *
-	 * Showing dangling objects is valid, though (as those
-	 * dangling objects are likely lost heads).
-	 *
-	 * So we just print a warning about it, and clear the
-	 * "show_unreachable" flag.
-	 */
-	if (!default_refs) {
-		error("No default references");
-		show_unreachable = 0;
-	}
-}
-
-static void fsck_object_dir(const char *path)
-{
-	int i;
-	for (i = 0; i < 256; i++) {
-		static char dir[4096];
-		sprintf(dir, "%s/%02x", path, i);
-		fsck_dir(i, dir);
-	}
-	fsck_sha1_list();
-}
-
-static int fsck_head_link(void)
-{
-	unsigned char sha1[20];
-	int flag;
-	const char *head_points_at = resolve_ref("HEAD", sha1, 1, &flag);
-
-	if (!head_points_at || !(flag & REF_ISSYMREF))
-		return error("HEAD is not a symbolic ref");
-	if (strncmp(head_points_at, "refs/heads/", 11))
-		return error("HEAD points to something strange (%s)",
-			     head_points_at);
-	if (is_null_sha1(sha1))
-		return error("HEAD: not a valid git pointer");
-	return 0;
-}
-
-static int fsck_cache_tree(struct cache_tree *it)
-{
-	int i;
-	int err = 0;
-
-	if (0 <= it->entry_count) {
-		struct object *obj = parse_object(it->sha1);
-		if (!obj) {
-			error("%s: invalid sha1 pointer in cache-tree",
-			      sha1_to_hex(it->sha1));
-			return 1;
-		}
-		mark_reachable(obj, REACHABLE);
-		obj->used = 1;
-		if (obj->type != OBJ_TREE)
-			err |= objerror(obj, "non-tree in cache-tree");
-	}
-	for (i = 0; i < it->subtree_nr; i++)
-		err |= fsck_cache_tree(it->down[i]->cache_tree);
-	return err;
-}
-
-int main(int argc, char **argv)
-{
-	int i, heads;
-
-	track_object_refs = 1;
-	setup_git_directory();
-
-	for (i = 1; i < argc; i++) {
-		const char *arg = argv[i];
-
-		if (!strcmp(arg, "--unreachable")) {
-			show_unreachable = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--tags")) {
-			show_tags = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--root")) {
-			show_root = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--cache")) {
-			keep_cache_objects = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--full")) {
-			check_full = 1;
-			continue;
-		}
-		if (!strcmp(arg, "--strict")) {
-			check_strict = 1;
-			continue;
-		}
-		if (*arg == '-')
-			usage("git-fsck [--tags] [--root] [[--unreachable] [--cache] [--full] [--strict] <head-sha1>*]");
-	}
-
-	fsck_head_link();
-	fsck_object_dir(get_object_directory());
-	if (check_full) {
-		struct alternate_object_database *alt;
-		struct packed_git *p;
-		prepare_alt_odb();
-		for (alt = alt_odb_list; alt; alt = alt->next) {
-			char namebuf[PATH_MAX];
-			int namelen = alt->name - alt->base;
-			memcpy(namebuf, alt->base, namelen);
-			namebuf[namelen - 1] = 0;
-			fsck_object_dir(namebuf);
-		}
-		prepare_packed_git();
-		for (p = packed_git; p; p = p->next)
-			/* verify gives error messages itself */
-			verify_pack(p, 0);
-
-		for (p = packed_git; p; p = p->next) {
-			int num = num_packed_objects(p);
-			for (i = 0; i < num; i++) {
-				unsigned char sha1[20];
-				nth_packed_object_sha1(p, i, sha1);
-				fsck_sha1(sha1);
-			}
-		}
-	}
-
-	heads = 0;
-	for (i = 1; i < argc; i++) {
-		const char *arg = argv[i]; 
-
-		if (*arg == '-')
-			continue;
-
-		if (!get_sha1(arg, head_sha1)) {
-			struct object *obj = lookup_object(head_sha1);
-
-			/* Error is printed by lookup_object(). */
-			if (!obj)
-				continue;
-
-			obj->used = 1;
-			mark_reachable(obj, REACHABLE);
-			heads++;
-			continue;
-		}
-		error("invalid parameter: expected sha1, got '%s'", arg);
-	}
-
-	/*
-	 * If we've not been given any explicit head information, do the
-	 * default ones from .git/refs. We also consider the index file
-	 * in this case (ie this implies --cache).
-	 */
-	if (!heads) {
-		get_default_heads();
-		keep_cache_objects = 1;
-	}
-
-	if (keep_cache_objects) {
-		int i;
-		read_cache();
-		for (i = 0; i < active_nr; i++) {
-			struct blob *blob = lookup_blob(active_cache[i]->sha1);
-			struct object *obj;
-			if (!blob)
-				continue;
-			obj = &blob->object;
-			obj->used = 1;
-			mark_reachable(obj, REACHABLE);
-		}
-		if (active_cache_tree)
-			fsck_cache_tree(active_cache_tree);
-	}
-
-	check_connectivity();
-	return 0;
+	error(sb.buf);
+	strbuf_release(&sb);
+	return 1;
 }