Merge branch 'rs/ref-transaction'

The API to update refs have been restructured to allow introducing
a true transactional updates later.  We would even allow storing
refs in backends other than the traditional filesystem-based one.

* rs/ref-transaction: (25 commits)
  ref_transaction_commit: bail out on failure to remove a ref
  lockfile: remove unable_to_lock_error
  refs.c: do not permit err == NULL
  remote rm/prune: print a message when writing packed-refs fails
  for-each-ref: skip and warn about broken ref names
  refs.c: allow listing and deleting badly named refs
  test: put tests for handling of bad ref names in one place
  packed-ref cache: forbid dot-components in refnames
  branch -d: simplify by using RESOLVE_REF_READING
  branch -d: avoid repeated symref resolution
  reflog test: test interaction with detached HEAD
  refs.c: change resolve_ref_unsafe reading argument to be a flags field
  refs.c: make write_ref_sha1 static
  fetch.c: change s_update_ref to use a ref transaction
  refs.c: ref_transaction_commit: distinguish name conflicts from other errors
  refs.c: pass a list of names to skip to is_refname_available
  refs.c: call lock_ref_sha1_basic directly from commit
  refs.c: refuse to lock badly named refs in lock_ref_sha1_basic
  rename_ref: don't ask read_ref_full where the ref came from
  refs.c: pass the ref log message to _create/delete/update instead of _commit
  ...

Author: gitster

branch.c

@@ -170,7 +170,7 @@ int validate_new_branchname(const char *name, struct strbuf *ref,
 		const char *head;
 		unsigned char sha1[20];
 
-		head = resolve_ref_unsafe("HEAD", sha1, 0, NULL);
+		head = resolve_ref_unsafe("HEAD", 0, sha1, NULL);
 		if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 			die(_("Cannot force update the current branch."));
 	}
@@ -285,8 +285,8 @@ void create_branch(const char *head,
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
 		    ref_transaction_update(transaction, ref.buf, sha1,
-					   null_sha1, 0, !forcing, &err) ||
-		    ref_transaction_commit(transaction, msg, &err))
+					   null_sha1, 0, !forcing, msg, &err) ||
+		    ref_transaction_commit(transaction, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);

builtin/blame.c

@@ -2286,7 +2286,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	commit->date = now;
 	parent_tail = &commit->parents;
 
-	if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
+	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_sha1, NULL))
 		die("no such ref: HEAD");
 
 	parent_tail = append_parent(parent_tail, head_sha1);

builtin/branch.c

@@ -130,7 +130,8 @@ static int branch_merged(int kind, const char *name,
 		    branch->merge[0] &&
 		    branch->merge[0]->dst &&
 		    (reference_name = reference_name_to_free =
-		     resolve_refdup(branch->merge[0]->dst, sha1, 1, NULL)) != NULL)
+		     resolve_refdup(branch->merge[0]->dst, RESOLVE_REF_READING,
+				    sha1, NULL)) != NULL)
 			reference_rev = lookup_commit_reference(sha1);
 	}
 	if (!reference_rev)
@@ -234,17 +235,20 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		free(name);
 
 		name = mkpathdup(fmt, bname.buf);
-		target = resolve_ref_unsafe(name, sha1, 0, &flags);
-		if (!target ||
-		    (!(flags & REF_ISSYMREF) && is_null_sha1(sha1))) {
+		target = resolve_ref_unsafe(name,
+					    RESOLVE_REF_READING
+					    | RESOLVE_REF_NO_RECURSE
+					    | RESOLVE_REF_ALLOW_BAD_NAME,
+					    sha1, &flags);
+		if (!target) {
 			error(remote_branch
 			      ? _("remote branch '%s' not found.")
 			      : _("branch '%s' not found."), bname.buf);
 			ret = 1;
 			continue;
 		}
 
-		if (!(flags & REF_ISSYMREF) &&
+		if (!(flags & (REF_ISSYMREF|REF_ISBROKEN)) &&
 		    check_branch_commit(bname.buf, name, sha1, head_rev, kinds,
 					force)) {
 			ret = 1;
@@ -264,8 +268,8 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			       ? _("Deleted remote branch %s (was %s).\n")
 			       : _("Deleted branch %s (was %s).\n"),
 			       bname.buf,
-			       (flags & REF_ISSYMREF)
-			       ? target
+			       (flags & REF_ISBROKEN) ? "broken"
+			       : (flags & REF_ISSYMREF) ? target
 			       : find_unique_abbrev(sha1, DEFAULT_ABBREV));
 		}
 		delete_branch_config(bname.buf);
@@ -298,7 +302,7 @@ static char *resolve_symref(const char *src, const char *prefix)
 	int flag;
 	const char *dst;
 
-	dst = resolve_ref_unsafe(src, sha1, 0, &flag);
+	dst = resolve_ref_unsafe(src, 0, sha1, &flag);
 	if (!(dst && (flag & REF_ISSYMREF)))
 		return NULL;
 	if (prefix)
@@ -868,7 +872,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 	track = git_branch_track;
 
-	head = resolve_refdup("HEAD", head_sha1, 0, NULL);
+	head = resolve_refdup("HEAD", 0, head_sha1, NULL);
 	if (!head)
 		die(_("Failed to resolve HEAD as a valid ref."));
 	if (!strcmp(head, "HEAD"))

builtin/checkout.c

@@ -355,7 +355,7 @@ static int checkout_paths(const struct checkout_opts *opts,
 	if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
 		die(_("unable to write new index file"));
 
-	read_ref_full("HEAD", rev, 0, &flag);
+	read_ref_full("HEAD", 0, rev, &flag);
 	head = lookup_commit_reference_gently(rev, 1);
 
 	errs |= post_checkout_hook(head, head, 0);
@@ -775,7 +775,7 @@ static int switch_branches(const struct checkout_opts *opts,
 	unsigned char rev[20];
 	int flag, writeout_error = 0;
 	memset(&old, 0, sizeof(old));
-	old.path = path_to_free = resolve_refdup("HEAD", rev, 0, &flag);
+	old.path = path_to_free = resolve_refdup("HEAD", 0, rev, &flag);
 	old.commit = lookup_commit_reference_gently(rev, 1);
 	if (!(flag & REF_ISSYMREF))
 		old.path = NULL;
@@ -1072,7 +1072,7 @@ static int checkout_branch(struct checkout_opts *opts,
 		unsigned char rev[20];
 		int flag;
 
-		if (!read_ref_full("HEAD", rev, 0, &flag) &&
+		if (!read_ref_full("HEAD", 0, rev, &flag) &&
 		    (flag & REF_ISSYMREF) && is_null_sha1(rev))
 			return switch_unborn_to_new_branch(opts);
 	}

builtin/clone.c

@@ -623,7 +623,7 @@ static int checkout(void)
 	if (option_no_checkout)
 		return 0;
 
-	head = resolve_refdup("HEAD", sha1, 1, NULL);
+	head = resolve_refdup("HEAD", RESOLVE_REF_READING, sha1, NULL);
 	if (!head) {
 		warning(_("remote HEAD refers to nonexistent ref, "
 			  "unable to checkout.\n"));

builtin/commit.c

@@ -1513,7 +1513,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", junk_sha1, 0, NULL);
+	head = resolve_ref_unsafe("HEAD", 0, junk_sha1, NULL);
 	if (!strcmp(head, "HEAD"))
 		head = _("detached HEAD");
 	else
@@ -1809,8 +1809,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	    ref_transaction_update(transaction, "HEAD", sha1,
 				   current_head
 				   ? current_head->object.sha1 : NULL,
-				   0, !!current_head, &err) ||
-	    ref_transaction_commit(transaction, sb.buf, &err)) {
+				   0, !!current_head, sb.buf, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		rollback_index_files();
 		die("%s", err.buf);
 	}

builtin/fetch.c

@@ -404,23 +404,37 @@ static int s_update_ref(const char *action,
 {
 	char msg[1024];
 	char *rla = getenv("GIT_REFLOG_ACTION");
-	static struct ref_lock *lock;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
+	int ret, df_conflict = 0;
 
 	if (dry_run)
 		return 0;
 	if (!rla)
 		rla = default_rla.buf;
 	snprintf(msg, sizeof(msg), "%s: %s", rla, action);
-	lock = lock_any_ref_for_update(ref->name,
-				       check_old ? ref->old_sha1 : NULL,
-				       0, NULL);
-	if (!lock)
-		return errno == ENOTDIR ? STORE_REF_ERROR_DF_CONFLICT :
-					  STORE_REF_ERROR_OTHER;
-	if (write_ref_sha1(lock, ref->new_sha1, msg) < 0)
-		return errno == ENOTDIR ? STORE_REF_ERROR_DF_CONFLICT :
-					  STORE_REF_ERROR_OTHER;
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref->name, ref->new_sha1,
+				   ref->old_sha1, 0, check_old, msg, &err))
+		goto fail;
+
+	ret = ref_transaction_commit(transaction, &err);
+	if (ret) {
+		df_conflict = (ret == TRANSACTION_NAME_CONFLICT);
+		goto fail;
+	}
+
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
+fail:
+	ref_transaction_free(transaction);
+	error("%s", err.buf);
+	strbuf_release(&err);
+	return df_conflict ? STORE_REF_ERROR_DF_CONFLICT
+			   : STORE_REF_ERROR_OTHER;
 }
 
 #define REFCOL_WIDTH  10

builtin/fmt-merge-msg.c

@@ -602,7 +602,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
 	/* get current branch */
 	current_branch = current_branch_to_free =
-		resolve_refdup("HEAD", head_sha1, 1, NULL);
+		resolve_refdup("HEAD", RESOLVE_REF_READING, head_sha1, NULL);
 	if (!current_branch)
 		die("No current branch");
 	if (starts_with(current_branch, "refs/heads/"))

builtin/for-each-ref.c

@@ -635,7 +635,8 @@ static void populate_value(struct refinfo *ref)
 
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
 		unsigned char unused1[20];
-		ref->symref = resolve_refdup(ref->refname, unused1, 1, NULL);
+		ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
+					     unused1, NULL);
 		if (!ref->symref)
 			ref->symref = "";
 	}
@@ -694,7 +695,8 @@ static void populate_value(struct refinfo *ref)
 			const char *head;
 			unsigned char sha1[20];
 
-			head = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
+			head = resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
+						  sha1, NULL);
 			if (!strcmp(ref->refname, head))
 				v->s = "*";
 			else
@@ -838,6 +840,11 @@ static int grab_single_ref(const char *refname, const unsigned char *sha1, int f
 	struct refinfo *ref;
 	int cnt;
 
+	if (flag & REF_BAD_NAME) {
+		  warning("ignoring ref with broken name %s", refname);
+		  return 0;
+	}
+
 	if (*cb->grab_pattern) {
 		const char **pattern;
 		int namelen = strlen(refname);

builtin/fsck.c

@@ -556,7 +556,7 @@ static int fsck_head_link(void)
 	if (verbose)
 		fprintf(stderr, "Checking HEAD link\n");
 
-	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, 0, &flag);
+	head_points_at = resolve_ref_unsafe("HEAD", 0, head_sha1, &flag);
 	if (!head_points_at)
 		return error("Invalid HEAD");
 	if (!strcmp(head_points_at, "HEAD"))