Add a place for (not) sharing stuff between worktrees
[gitweb.git] / refs / files-backend.c
index a80d60aa068e943fbefe392948df2c9dde6f3df0..2dd77f9485ea19b1e850851be2c0a0ef9b342ace 100644 (file)
@@ -9,6 +9,52 @@
 #include "../lockfile.h"
 #include "../object.h"
 #include "../dir.h"
+#include "../chdir-notify.h"
+
+/*
+ * This backend uses the following flags in `ref_update::flags` for
+ * internal bookkeeping purposes. Their numerical values must not
+ * conflict with REF_NO_DEREF, REF_FORCE_CREATE_REFLOG, REF_HAVE_NEW,
+ * REF_HAVE_OLD, or REF_IS_PRUNING, which are also stored in
+ * `ref_update::flags`.
+ */
+
+/*
+ * Used as a flag in ref_update::flags when a loose ref is being
+ * pruned. This flag must only be used when REF_NO_DEREF is set.
+ */
+#define REF_IS_PRUNING (1 << 4)
+
+/*
+ * Flag passed to lock_ref_sha1_basic() telling it to tolerate broken
+ * refs (i.e., because the reference is about to be deleted anyway).
+ */
+#define REF_DELETING (1 << 5)
+
+/*
+ * Used as a flag in ref_update::flags when the lockfile needs to be
+ * committed.
+ */
+#define REF_NEEDS_COMMIT (1 << 6)
+
+/*
+ * Used as a flag in ref_update::flags when we want to log a ref
+ * update but not actually perform it.  This is used when a symbolic
+ * ref update is split up.
+ */
+#define REF_LOG_ONLY (1 << 7)
+
+/*
+ * Used as a flag in ref_update::flags when the ref_update was via an
+ * update to HEAD.
+ */
+#define REF_UPDATE_VIA_HEAD (1 << 8)
+
+/*
+ * Used as a flag in ref_update::flags when the loose reference has
+ * been deleted.
+ */
+#define REF_DELETED_LOOSE (1 << 9)
 
 struct ref_lock {
        char *ref_name;
@@ -16,10 +62,6 @@ struct ref_lock {
        struct object_id old_oid;
 };
 
-/*
- * Future: need to be in "struct repository"
- * when doing a full libification.
- */
 struct files_ref_store {
        struct ref_store base;
        unsigned int store_flags;
@@ -61,6 +103,11 @@ static struct ref_store *files_ref_store_create(const char *gitdir,
        refs->packed_ref_store = packed_ref_store_create(sb.buf, flags);
        strbuf_release(&sb);
 
+       chdir_notify_reparent("files-backend $GIT_DIR",
+                             &refs->gitdir);
+       chdir_notify_reparent("files-backend $GIT_COMMONDIR",
+                             &refs->gitcommondir);
+
        return ref_store;
 }
 
@@ -74,7 +121,7 @@ static void files_assert_main_repository(struct files_ref_store *refs,
        if (refs->store_flags & REF_STORE_MAIN)
                return;
 
-       die("BUG: operation %s only allowed for main ref store", caller);
+       BUG("operation %s only allowed for main ref store", caller);
 }
 
 /*
@@ -90,13 +137,13 @@ static struct files_ref_store *files_downcast(struct ref_store *ref_store,
        struct files_ref_store *refs;
 
        if (ref_store->be != &refs_be_files)
-               die("BUG: ref_store is type \"%s\" not \"files\" in %s",
+               BUG("ref_store is type \"%s\" not \"files\" in %s",
                    ref_store->be->name, caller);
 
        refs = (struct files_ref_store *)ref_store;
 
        if ((refs->store_flags & required_flags) != required_flags)
-               die("BUG: operation %s requires abilities 0x%x, but only have 0x%x",
+               BUG("operation %s requires abilities 0x%x, but only have 0x%x",
                    caller, required_flags, refs->store_flags);
 
        return refs;
@@ -115,7 +162,7 @@ static void files_reflog_path(struct files_ref_store *refs,
                strbuf_addf(sb, "%s/logs/%s", refs->gitcommondir, refname);
                break;
        default:
-               die("BUG: unknown ref type %d of ref %s",
+               BUG("unknown ref type %d of ref %s",
                    ref_type(refname), refname);
        }
 }
@@ -133,7 +180,7 @@ static void files_ref_path(struct files_ref_store *refs,
                strbuf_addf(sb, "%s/%s", refs->gitcommondir, refname);
                break;
        default:
-               die("BUG: unknown ref type %d of ref %s",
+               BUG("unknown ref type %d of ref %s",
                    ref_type(refname), refname);
        }
 }
@@ -189,13 +236,13 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
                        if (!refs_resolve_ref_unsafe(&refs->base,
                                                     refname.buf,
                                                     RESOLVE_REF_READING,
-                                                    oid.hash, &flag)) {
+                                                    &oid, &flag)) {
                                oidclr(&oid);
                                flag |= REF_ISBROKEN;
                        } else if (is_null_oid(&oid)) {
                                /*
                                 * It is so astronomically unlikely
-                                * that NULL_SHA1 is the SHA-1 of an
+                                * that null_oid is the OID of an
                                 * actual object that we consider its
                                 * appearance in a loose reference
                                 * file to be repo corruption
@@ -222,9 +269,9 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
        closedir(d);
 
        /*
-        * Manually add refs/bisect, which, being per-worktree, might
-        * not appear in the directory listing for refs/ in the main
-        * repo.
+        * Manually add refs/bisect and refs/worktree, which, being
+        * per-worktree, might not appear in the directory listing for
+        * refs/ in the main repo.
         */
        if (!strcmp(dirname, "refs/")) {
                int pos = search_ref_dir(dir, "refs/bisect/", 12);
@@ -234,6 +281,14 @@ static void loose_fill_ref_dir(struct ref_store *ref_store,
                                        dir->cache, "refs/bisect/", 12, 1);
                        add_entry_to_dir(dir, child_entry);
                }
+
+               pos = search_ref_dir(dir, "refs/worktree/", 11);
+
+               if (pos < 0) {
+                       struct ref_entry *child_entry = create_dir_entry(
+                                       dir->cache, "refs/worktree/", 11, 1);
+                       add_entry_to_dir(dir, child_entry);
+               }
        }
 }
 
@@ -261,7 +316,7 @@ static struct ref_cache *get_loose_ref_cache(struct files_ref_store *refs)
 }
 
 static int files_read_raw_ref(struct ref_store *ref_store,
-                             const char *refname, unsigned char *sha1,
+                             const char *refname, struct object_id *oid,
                              struct strbuf *referent, unsigned int *type)
 {
        struct files_ref_store *refs =
@@ -270,6 +325,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
        struct strbuf sb_path = STRBUF_INIT;
        const char *path;
        const char *buf;
+       const char *p;
        struct stat st;
        int fd;
        int ret = -1;
@@ -304,7 +360,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
                if (errno != ENOENT)
                        goto out;
                if (refs_read_raw_ref(refs->packed_ref_store, refname,
-                                     sha1, referent, type)) {
+                                     oid, referent, type)) {
                        errno = ENOENT;
                        goto out;
                }
@@ -315,7 +371,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
        /* Follow "normalized" - ie "refs/.." symlinks by hand */
        if (S_ISLNK(st.st_mode)) {
                strbuf_reset(&sb_contents);
-               if (strbuf_readlink(&sb_contents, path, 0) < 0) {
+               if (strbuf_readlink(&sb_contents, path, st.st_size) < 0) {
                        if (errno == ENOENT || errno == EINVAL)
                                /* inconsistent with lstat; retry */
                                goto stat_ref;
@@ -344,7 +400,7 @@ static int files_read_raw_ref(struct ref_store *ref_store,
                 * packed ref:
                 */
                if (refs_read_raw_ref(refs->packed_ref_store, refname,
-                                     sha1, referent, type)) {
+                                     oid, referent, type)) {
                        errno = EISDIR;
                        goto out;
                }
@@ -390,8 +446,8 @@ static int files_read_raw_ref(struct ref_store *ref_store,
         * Please note that FETCH_HEAD has additional
         * data after the sha.
         */
-       if (get_sha1_hex(buf, sha1) ||
-           (buf[40] != '\0' && !isspace(buf[40]))) {
+       if (parse_oid_hex(buf, oid, &p) ||
+           (*p != '\0' && !isspace(*p))) {
                *type |= REF_ISBROKEN;
                errno = EINVAL;
                goto out;
@@ -427,7 +483,7 @@ static void unlock_ref(struct ref_lock *lock)
  * are passed to refs_verify_refname_available() for this check.
  *
  * If mustexist is not set and the reference is not found or is
- * broken, lock the reference anyway but clear sha1.
+ * broken, lock the reference anyway but clear old_oid.
  *
  * Return 0 on success. On failure, write an error message to err and
  * return TRANSACTION_NAME_CONFLICT or TRANSACTION_GENERIC_ERROR.
@@ -545,7 +601,7 @@ static int lock_raw_ref(struct files_ref_store *refs,
         */
 
        if (files_read_raw_ref(&refs->base, refname,
-                              lock->old_oid.hash, referent, type)) {
+                              &lock->old_oid, referent, type)) {
                if (errno == ENOENT) {
                        if (mustexist) {
                                /* Garden variety missing reference. */
@@ -769,21 +825,21 @@ static struct ref_iterator *files_ref_iterator_begin(
 }
 
 /*
- * Verify that the reference locked by lock has the value old_sha1.
- * Fail if the reference doesn't exist and mustexist is set. Return 0
- * on success. On error, write an error message to err, set errno, and
- * return a negative value.
+ * Verify that the reference locked by lock has the value old_oid
+ * (unless it is NULL).  Fail if the reference doesn't exist and
+ * mustexist is set. Return 0 on success. On error, write an error
+ * message to err, set errno, and return a negative value.
  */
 static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
-                      const unsigned char *old_sha1, int mustexist,
+                      const struct object_id *old_oid, int mustexist,
                       struct strbuf *err)
 {
        assert(err);
 
        if (refs_read_ref_full(ref_store, lock->ref_name,
                               mustexist ? RESOLVE_REF_READING : 0,
-                              lock->old_oid.hash, NULL)) {
-               if (old_sha1) {
+                              &lock->old_oid, NULL)) {
+               if (old_oid) {
                        int save_errno = errno;
                        strbuf_addf(err, "can't verify ref '%s'", lock->ref_name);
                        errno = save_errno;
@@ -793,11 +849,11 @@ static int verify_lock(struct ref_store *ref_store, struct ref_lock *lock,
                        return 0;
                }
        }
-       if (old_sha1 && hashcmp(lock->old_oid.hash, old_sha1)) {
+       if (old_oid && !oideq(&lock->old_oid, old_oid)) {
                strbuf_addf(err, "ref '%s' is at %s but expected %s",
                            lock->ref_name,
                            oid_to_hex(&lock->old_oid),
-                           sha1_to_hex(old_sha1));
+                           oid_to_hex(old_oid));
                errno = EBUSY;
                return -1;
        }
@@ -827,22 +883,22 @@ static int create_reflock(const char *path, void *cb)
  * Locks a ref returning the lock on success and NULL on failure.
  * On failure errno is set to something meaningful.
  */
-static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
-                                           const char *refname,
-                                           const unsigned char *old_sha1,
-                                           const struct string_list *extras,
-                                           const struct string_list *skip,
-                                           unsigned int flags, int *type,
-                                           struct strbuf *err)
+static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
+                                          const char *refname,
+                                          const struct object_id *old_oid,
+                                          const struct string_list *extras,
+                                          const struct string_list *skip,
+                                          unsigned int flags, int *type,
+                                          struct strbuf *err)
 {
        struct strbuf ref_file = STRBUF_INIT;
        struct ref_lock *lock;
        int last_errno = 0;
-       int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
+       int mustexist = (old_oid && !is_null_oid(old_oid));
        int resolve_flags = RESOLVE_REF_NO_RECURSE;
        int resolved;
 
-       files_assert_main_repository(refs, "lock_ref_sha1_basic");
+       files_assert_main_repository(refs, "lock_ref_oid_basic");
        assert(err);
 
        lock = xcalloc(1, sizeof(struct ref_lock));
@@ -855,7 +911,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
        files_ref_path(refs, &ref_file, refname);
        resolved = !!refs_resolve_ref_unsafe(&refs->base,
                                             refname, resolve_flags,
-                                            lock->old_oid.hash, type);
+                                            &lock->old_oid, type);
        if (!resolved && errno == EISDIR) {
                /*
                 * we are trying to lock foo but we used to
@@ -874,7 +930,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
                }
                resolved = !!refs_resolve_ref_unsafe(&refs->base,
                                                     refname, resolve_flags,
-                                                    lock->old_oid.hash, type);
+                                                    &lock->old_oid, type);
        }
        if (!resolved) {
                last_errno = errno;
@@ -908,7 +964,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
                goto error_return;
        }
 
-       if (verify_lock(&refs->base, lock, old_sha1, mustexist, err)) {
+       if (verify_lock(&refs->base, lock, old_oid, mustexist, err)) {
                last_errno = errno;
                goto error_return;
        }
@@ -926,7 +982,7 @@ static struct ref_lock *lock_ref_sha1_basic(struct files_ref_store *refs,
 
 struct ref_to_prune {
        struct ref_to_prune *next;
-       unsigned char sha1[20];
+       struct object_id oid;
        char name[FLEX_ARRAY];
 };
 
@@ -988,22 +1044,29 @@ static void prune_ref(struct files_ref_store *refs, struct ref_to_prune *r)
 {
        struct ref_transaction *transaction;
        struct strbuf err = STRBUF_INIT;
+       int ret = -1;
 
        if (check_refname_format(r->name, 0))
                return;
 
        transaction = ref_store_transaction_begin(&refs->base, &err);
-       if (!transaction ||
-           ref_transaction_delete(transaction, r->name, r->sha1,
-                                  REF_ISPRUNING | REF_NODEREF, NULL, &err) ||
-           ref_transaction_commit(transaction, &err)) {
-               ref_transaction_free(transaction);
+       if (!transaction)
+               goto cleanup;
+       ref_transaction_add_update(
+                       transaction, r->name,
+                       REF_NO_DEREF | REF_HAVE_NEW | REF_HAVE_OLD | REF_IS_PRUNING,
+                       &null_oid, &r->oid, NULL);
+       if (ref_transaction_commit(transaction, &err))
+               goto cleanup;
+
+       ret = 0;
+
+cleanup:
+       if (ret)
                error("%s", err.buf);
-               strbuf_release(&err);
-               return;
-       }
-       ref_transaction_free(transaction);
        strbuf_release(&err);
+       ref_transaction_free(transaction);
+       return;
 }
 
 /*
@@ -1079,8 +1142,8 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
                 * packed-refs transaction:
                 */
                if (ref_transaction_update(transaction, iter->refname,
-                                          iter->oid->hash, NULL,
-                                          REF_NODEREF, NULL, &err))
+                                          iter->oid, NULL,
+                                          REF_NO_DEREF, NULL, &err))
                        die("failure preparing to create packed reference %s: %s",
                            iter->refname, err.buf);
 
@@ -1088,7 +1151,7 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
                if ((flags & PACK_REFS_PRUNE)) {
                        struct ref_to_prune *n;
                        FLEX_ALLOC_STR(n, name, iter->refname);
-                       hashcpy(n->sha1, iter->oid->hash);
+                       oidcpy(&n->oid, iter->oid);
                        n->next = refs_to_prune;
                        refs_to_prune = n;
                }
@@ -1251,7 +1314,7 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
 
        if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
                                     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-                               orig_oid.hash, &flag)) {
+                               &orig_oid, &flag)) {
                ret = error("refname %s not found", oldrefname);
                goto out;
        }
@@ -1283,7 +1346,7 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
        }
 
        if (!copy && refs_delete_ref(&refs->base, logmsg, oldrefname,
-                           orig_oid.hash, REF_NODEREF)) {
+                           &orig_oid, REF_NO_DEREF)) {
                error("unable to delete old %s", oldrefname);
                goto rollback;
        }
@@ -1297,9 +1360,9 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
         */
        if (!copy && !refs_read_ref_full(&refs->base, newrefname,
                                RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-                               oid.hash, NULL) &&
+                               &oid, NULL) &&
            refs_delete_ref(&refs->base, NULL, newrefname,
-                           NULL, REF_NODEREF)) {
+                           NULL, REF_NO_DEREF)) {
                if (errno == EISDIR) {
                        struct strbuf path = STRBUF_INIT;
                        int result;
@@ -1323,8 +1386,8 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
 
        logmoved = log;
 
-       lock = lock_ref_sha1_basic(refs, newrefname, NULL, NULL, NULL,
-                                  REF_NODEREF, NULL, &err);
+       lock = lock_ref_oid_basic(refs, newrefname, NULL, NULL, NULL,
+                                 REF_NO_DEREF, NULL, &err);
        if (!lock) {
                if (copy)
                        error("unable to copy '%s' to '%s': %s", oldrefname, newrefname, err.buf);
@@ -1346,8 +1409,8 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
        goto out;
 
  rollback:
-       lock = lock_ref_sha1_basic(refs, oldrefname, NULL, NULL, NULL,
-                                  REF_NODEREF, NULL, &err);
+       lock = lock_ref_oid_basic(refs, oldrefname, NULL, NULL, NULL,
+                                 REF_NO_DEREF, NULL, &err);
        if (!lock) {
                error("unable to lock %s for rollback: %s", oldrefname, err.buf);
                strbuf_release(&err);
@@ -1527,26 +1590,17 @@ static int log_ref_write_fd(int fd, const struct object_id *old_oid,
                            const struct object_id *new_oid,
                            const char *committer, const char *msg)
 {
-       int msglen, written;
-       unsigned maxlen, len;
-       char *logrec;
-
-       msglen = msg ? strlen(msg) : 0;
-       maxlen = strlen(committer) + msglen + 100;
-       logrec = xmalloc(maxlen);
-       len = xsnprintf(logrec, maxlen, "%s %s %s\n",
-                       oid_to_hex(old_oid),
-                       oid_to_hex(new_oid),
-                       committer);
-       if (msglen)
-               len += copy_reflog_msg(logrec + len - 1, msg) - 1;
-
-       written = len <= maxlen ? write_in_full(fd, logrec, len) : -1;
-       free(logrec);
-       if (written < 0)
-               return -1;
+       struct strbuf sb = STRBUF_INIT;
+       int ret = 0;
 
-       return 0;
+       strbuf_addf(&sb, "%s %s %s", oid_to_hex(old_oid), oid_to_hex(new_oid), committer);
+       if (msg && *msg)
+               copy_reflog_msg(&sb, msg);
+       strbuf_addch(&sb, '\n');
+       if (write_in_full(fd, sb.buf, sb.len) < 0)
+               ret = -1;
+       strbuf_release(&sb);
+       return ret;
 }
 
 static int files_log_ref_write(struct files_ref_store *refs,
@@ -1595,9 +1649,8 @@ static int files_log_ref_write(struct files_ref_store *refs,
 }
 
 /*
- * Write sha1 into the open lockfile, then close the lockfile. On
- * errors, rollback the lockfile, fill in *err and
- * return -1.
+ * Write oid into the open lockfile, then close the lockfile. On
+ * errors, rollback the lockfile, fill in *err and return -1.
  */
 static int write_ref_to_lockfile(struct ref_lock *lock,
                                 const struct object_id *oid, struct strbuf *err)
@@ -1606,7 +1659,7 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
        struct object *o;
        int fd;
 
-       o = parse_object(oid);
+       o = parse_object(the_repository, oid);
        if (!o) {
                strbuf_addf(err,
                            "trying to write ref '%s' with nonexistent object %s",
@@ -1622,7 +1675,7 @@ static int write_ref_to_lockfile(struct ref_lock *lock,
                return -1;
        }
        fd = get_lock_file_fd(&lock->lk);
-       if (write_in_full(fd, oid_to_hex(oid), GIT_SHA1_HEXSZ) < 0 ||
+       if (write_in_full(fd, oid_to_hex(oid), the_hash_algo->hexsz) < 0 ||
            write_in_full(fd, &term, 1) < 0 ||
            close_ref_gently(lock) < 0) {
                strbuf_addf(err,
@@ -1721,7 +1774,7 @@ static void update_symref_reflog(struct files_ref_store *refs,
        struct object_id new_oid;
        if (logmsg &&
            !refs_read_ref_full(&refs->base, target,
-                               RESOLVE_REF_READING, new_oid.hash, NULL) &&
+                               RESOLVE_REF_READING, &new_oid, NULL) &&
            files_log_ref_write(refs, refname, &lock->old_oid,
                                &new_oid, logmsg, 0, &err)) {
                error("%s", err.buf);
@@ -1762,9 +1815,9 @@ static int files_create_symref(struct ref_store *ref_store,
        struct ref_lock *lock;
        int ret;
 
-       lock = lock_ref_sha1_basic(refs, refname, NULL,
-                                  NULL, NULL, REF_NODEREF, NULL,
-                                  &err);
+       lock = lock_ref_oid_basic(refs, refname, NULL,
+                                 NULL, NULL, REF_NO_DEREF, NULL,
+                                 &err);
        if (!lock) {
                error("%s", err.buf);
                strbuf_release(&err);
@@ -1952,7 +2005,7 @@ static int files_for_each_reflog_ent_reverse(struct ref_store *ref_store,
 
        }
        if (!ret && sb.len)
-               die("BUG: reverse reflog parser had leftover data");
+               BUG("reverse reflog parser had leftover data");
 
        fclose(logfp);
        strbuf_release(&sb);
@@ -2010,7 +2063,7 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 
                if (refs_read_ref_full(iter->ref_store,
                                       diter->relative_path, 0,
-                                      iter->oid.hash, &flags)) {
+                                      &iter->oid, &flags)) {
                        error("bad ref for %s", diter->path.buf);
                        continue;
                }
@@ -2030,7 +2083,7 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
                                   struct object_id *peeled)
 {
-       die("BUG: ref_iterator_peel() called for reflog_iterator");
+       BUG("ref_iterator_peel() called for reflog_iterator");
 }
 
 static int files_reflog_iterator_abort(struct ref_iterator *ref_iterator)
@@ -2124,7 +2177,7 @@ static int split_head_update(struct ref_update *update,
        struct ref_update *new_update;
 
        if ((update->flags & REF_LOG_ONLY) ||
-           (update->flags & REF_ISPRUNING) ||
+           (update->flags & REF_IS_PRUNING) ||
            (update->flags & REF_UPDATE_VIA_HEAD))
                return 0;
 
@@ -2147,8 +2200,8 @@ static int split_head_update(struct ref_update *update,
 
        new_update = ref_transaction_add_update(
                        transaction, "HEAD",
-                       update->flags | REF_LOG_ONLY | REF_NODEREF,
-                       update->new_oid.hash, update->old_oid.hash,
+                       update->flags | REF_LOG_ONLY | REF_NO_DEREF,
+                       &update->new_oid, &update->old_oid,
                        update->msg);
 
        /*
@@ -2166,8 +2219,8 @@ static int split_head_update(struct ref_update *update,
 
 /*
  * update is for a symref that points at referent and doesn't have
- * REF_NODEREF set. Split it into two updates:
- * - The original update, but with REF_LOG_ONLY and REF_NODEREF set
+ * REF_NO_DEREF set. Split it into two updates:
+ * - The original update, but with REF_LOG_ONLY and REF_NO_DEREF set
  * - A new, separate update for the referent reference
  * Note that the new update will itself be subject to splitting when
  * the iteration gets to it.
@@ -2212,17 +2265,17 @@ static int split_symref_update(struct files_ref_store *refs,
 
        new_update = ref_transaction_add_update(
                        transaction, referent, new_flags,
-                       update->new_oid.hash, update->old_oid.hash,
+                       &update->new_oid, &update->old_oid,
                        update->msg);
 
        new_update->parent_update = update;
 
        /*
         * Change the symbolic ref update to log only. Also, it
-        * doesn't need to check its old SHA-1 value, as that will be
+        * doesn't need to check its old OID value, as that will be
         * done when new_update is processed.
         */
-       update->flags |= REF_LOG_ONLY | REF_NODEREF;
+       update->flags |= REF_LOG_ONLY | REF_NO_DEREF;
        update->flags &= ~REF_HAVE_OLD;
 
        /*
@@ -2262,7 +2315,7 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid,
                         struct strbuf *err)
 {
        if (!(update->flags & REF_HAVE_OLD) ||
-                  !oidcmp(oid, &update->old_oid))
+                  oideq(oid, &update->old_oid))
                return 0;
 
        if (is_null_oid(&update->old_oid))
@@ -2288,10 +2341,10 @@ static int check_old_oid(struct ref_update *update, struct object_id *oid,
  * Prepare for carrying out update:
  * - Lock the reference referred to by update.
  * - Read the reference under lock.
- * - Check that its old SHA-1 value (if specified) is correct, and in
+ * - Check that its old OID value (if specified) is correct, and in
  *   any case record it in update->lock->old_oid for later use when
  *   writing the reflog.
- * - If it is a symref update without REF_NODEREF, split it up into a
+ * - If it is a symref update without REF_NO_DEREF, split it up into a
  *   REF_LOG_ONLY update of the symref and add a separate update for
  *   the referent to transaction.
  * - If it is an update of head_ref, add a corresponding REF_LOG_ONLY
@@ -2339,15 +2392,15 @@ static int lock_ref_for_update(struct files_ref_store *refs,
        update->backend_data = lock;
 
        if (update->type & REF_ISSYMREF) {
-               if (update->flags & REF_NODEREF) {
+               if (update->flags & REF_NO_DEREF) {
                        /*
                         * We won't be reading the referent as part of
                         * the transaction, so we have to read it here
-                        * to record and possibly check old_sha1:
+                        * to record and possibly check old_oid:
                         */
                        if (refs_read_ref_full(&refs->base,
                                               referent.buf, 0,
-                                              lock->old_oid.hash, NULL)) {
+                                              &lock->old_oid, NULL)) {
                                if (update->flags & REF_HAVE_OLD) {
                                        strbuf_addf(err, "cannot lock ref '%s': "
                                                    "error reading reference",
@@ -2363,7 +2416,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
                        /*
                         * Create a new update for the reference this
                         * symref is pointing at. Also, we will record
-                        * and verify old_sha1 for this update as part
+                        * and verify old_oid for this update as part
                         * of processing the split-off update, so we
                         * don't have to do it here.
                         */
@@ -2383,7 +2436,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
 
                /*
                 * If this update is happening indirectly because of a
-                * symref update, record the old SHA-1 in the parent
+                * symref update, record the old OID in the parent
                 * update:
                 */
                for (parent_update = update->parent_update;
@@ -2398,7 +2451,7 @@ static int lock_ref_for_update(struct files_ref_store *refs,
            !(update->flags & REF_DELETING) &&
            !(update->flags & REF_LOG_ONLY)) {
                if (!(update->type & REF_ISSYMREF) &&
-                   !oidcmp(&lock->old_oid, &update->new_oid)) {
+                   oideq(&lock->old_oid, &update->new_oid)) {
                        /*
                         * The reference already has the desired
                         * value, so we don't need to write it.
@@ -2510,13 +2563,18 @@ static int files_transaction_prepare(struct ref_store *ref_store,
         * transaction. (If we end up splitting up any updates using
         * split_symref_update() or split_head_update(), those
         * functions will check that the new updates don't have the
-        * same refname as any existing ones.)
+        * same refname as any existing ones.) Also fail if any of the
+        * updates use REF_IS_PRUNING without REF_NO_DEREF.
         */
        for (i = 0; i < transaction->nr; i++) {
                struct ref_update *update = transaction->updates[i];
                struct string_list_item *item =
                        string_list_append(&affected_refnames, update->refname);
 
+               if ((update->flags & REF_IS_PRUNING) &&
+                   !(update->flags & REF_NO_DEREF))
+                       BUG("REF_IS_PRUNING set without REF_NO_DEREF");
+
                /*
                 * We store a pointer to update in item->util, but at
                 * the moment we never use the value of this field
@@ -2574,7 +2632,7 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 
                if (update->flags & REF_DELETING &&
                    !(update->flags & REF_LOG_ONLY) &&
-                   !(update->flags & REF_ISPRUNING)) {
+                   !(update->flags & REF_IS_PRUNING)) {
                        /*
                         * This reference has to be deleted from
                         * packed-refs if it exists there.
@@ -2593,8 +2651,8 @@ static int files_transaction_prepare(struct ref_store *ref_store,
 
                        ref_transaction_add_update(
                                        packed_transaction, update->refname,
-                                       update->flags & ~REF_HAVE_OLD,
-                                       update->new_oid.hash, update->old_oid.hash,
+                                       REF_HAVE_NEW | REF_NO_DEREF,
+                                       &update->new_oid, NULL,
                                        NULL);
                }
        }
@@ -2707,7 +2765,7 @@ static int files_transaction_finish(struct ref_store *ref_store,
                struct ref_update *update = transaction->updates[i];
                if (update->flags & REF_DELETING &&
                    !(update->flags & REF_LOG_ONLY) &&
-                   !(update->flags & REF_ISPRUNING)) {
+                   !(update->flags & REF_IS_PRUNING)) {
                        strbuf_reset(&sb);
                        files_reflog_path(refs, &sb, update->refname);
                        if (!unlink_or_warn(sb.buf))
@@ -2810,7 +2868,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
        assert(err);
 
        if (transaction->state != REF_TRANSACTION_OPEN)
-               die("BUG: commit called for transaction that is not open");
+               BUG("commit called for transaction that is not open");
 
        /* Fail if a refname appears more than once in the transaction: */
        for (i = 0; i < transaction->nr; i++)
@@ -2836,7 +2894,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
         */
        if (refs_for_each_rawref(&refs->base, ref_present,
                                 &affected_refnames))
-               die("BUG: initial ref transaction called with existing refs");
+               BUG("initial ref transaction called with existing refs");
 
        packed_transaction = ref_store_transaction_begin(refs->packed_ref_store, err);
        if (!packed_transaction) {
@@ -2849,7 +2907,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 
                if ((update->flags & REF_HAVE_OLD) &&
                    !is_null_oid(&update->old_oid))
-                       die("BUG: initial ref transaction with old_sha1 set");
+                       BUG("initial ref transaction with old_sha1 set");
                if (refs_verify_refname_available(&refs->base, update->refname,
                                                  &affected_refnames, NULL,
                                                  err)) {
@@ -2863,7 +2921,7 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
                 */
                ref_transaction_add_update(packed_transaction, update->refname,
                                           update->flags & ~REF_HAVE_OLD,
-                                          update->new_oid.hash, update->old_oid.hash,
+                                          &update->new_oid, &update->old_oid,
                                           NULL);
        }
 
@@ -2874,13 +2932,12 @@ static int files_initial_transaction_commit(struct ref_store *ref_store,
 
        if (initial_ref_transaction_commit(packed_transaction, err)) {
                ret = TRANSACTION_GENERIC_ERROR;
-               goto cleanup;
        }
 
+       packed_refs_unlock(refs->packed_ref_store);
 cleanup:
        if (packed_transaction)
                ref_transaction_free(packed_transaction);
-       packed_refs_unlock(refs->packed_ref_store);
        transaction->state = REF_TRANSACTION_CLOSED;
        string_list_clear(&affected_refnames, 0);
        return ret;
@@ -2924,7 +2981,7 @@ static int expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
 }
 
 static int files_reflog_expire(struct ref_store *ref_store,
-                              const char *refname, const unsigned char *sha1,
+                              const char *refname, const struct object_id *oid,
                               unsigned int flags,
                               reflog_expiry_prepare_fn prepare_fn,
                               reflog_expiry_should_prune_fn should_prune_fn,
@@ -2933,7 +2990,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 {
        struct files_ref_store *refs =
                files_downcast(ref_store, REF_STORE_WRITE, "reflog_expire");
-       static struct lock_file reflog_lock;
+       struct lock_file reflog_lock = LOCK_INIT;
        struct expire_reflog_cb cb;
        struct ref_lock *lock;
        struct strbuf log_file_sb = STRBUF_INIT;
@@ -2941,7 +2998,6 @@ static int files_reflog_expire(struct ref_store *ref_store,
        int status = 0;
        int type;
        struct strbuf err = STRBUF_INIT;
-       struct object_id oid;
 
        memset(&cb, 0, sizeof(cb));
        cb.flags = flags;
@@ -2953,9 +3009,9 @@ static int files_reflog_expire(struct ref_store *ref_store,
         * reference itself, plus we might need to update the
         * reference if --updateref was specified:
         */
-       lock = lock_ref_sha1_basic(refs, refname, sha1,
-                                  NULL, NULL, REF_NODEREF,
-                                  &type, &err);
+       lock = lock_ref_oid_basic(refs, refname, oid,
+                                 NULL, NULL, REF_NO_DEREF,
+                                 &type, &err);
        if (!lock) {
                error("cannot lock ref '%s': %s", refname, err.buf);
                strbuf_release(&err);
@@ -2991,9 +3047,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
                }
        }
 
-       hashcpy(oid.hash, sha1);
-
-       (*prepare_fn)(refname, &oid, cb.policy_cb);
+       (*prepare_fn)(refname, oid, cb.policy_cb);
        refs_for_each_reflog_ent(ref_store, refname, expire_reflog_ent, &cb);
        (*cleanup_fn)(cb.policy_cb);
 
@@ -3015,7 +3069,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
                        rollback_lock_file(&reflog_lock);
                } else if (update &&
                           (write_in_full(get_lock_file_fd(&lock->lk),
-                               oid_to_hex(&cb.last_kept_oid), GIT_SHA1_HEXSZ) < 0 ||
+                               oid_to_hex(&cb.last_kept_oid), the_hash_algo->hexsz) < 0 ||
                            write_str_in_full(get_lock_file_fd(&lock->lk), "\n") < 0 ||
                            close_ref_gently(lock) < 0)) {
                        status |= error("couldn't write %s",