Merge branch 'ps/update-ref-multi-transaction'

"git update-ref --stdin" learns to take multiple transactions in a
single session.

* ps/update-ref-multi-transaction:
  update-ref: disallow "start" for ongoing transactions
  p1400: use `git-update-ref --stdin` to test multiple transactions
  update-ref: allow creation of multiple transactions
  t1400: avoid touching refs on filesystem

4 files changed, 126 insertions, 50 deletions

diff --git a/Documentation/git-update-ref.txt b/Documentation/git-update-ref.txt
index d401234b03..48b6683071 100644
--- a/Documentation/git-update-ref.txt
+++ b/Documentation/git-update-ref.txt
@@ -125,7 +125,8 @@ option::
 start::
 	Start a transaction. In contrast to a non-transactional session, a
 	transaction will automatically abort if the session ends without an
-	explicit commit.
+	explicit commit. This command may create a new empty transaction when
+	the current one has been committed or aborted already.
 
 prepare::
 	Prepare to commit the transaction. This will create lock files for all
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 8a2df4459c..6029a80544 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -436,6 +436,8 @@ static void update_refs_stdin(void)
 		switch (state) {
 		case UPDATE_REFS_OPEN:
 		case UPDATE_REFS_STARTED:
+			if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
+				die("cannot restart ongoing transaction");
 			/* Do not downgrade a transaction to a non-transaction. */
 			if (cmd->state >= state)
 				state = cmd->state;
@@ -446,7 +448,18 @@ static void update_refs_stdin(void)
 			state = cmd->state;
 			break;
 		case UPDATE_REFS_CLOSED:
-			die("transaction is closed");
+			if (cmd->state != UPDATE_REFS_STARTED)
+				die("transaction is closed");
+
+			/*
+			 * Open a new transaction if we're currently closed and
+			 * get a "start".
+			 */
+			state = cmd->state;
+			transaction = ref_transaction_begin(&err);
+			if (!transaction)
+				die("%s", err.buf);
+
 			break;
 		}
 
diff --git a/t/perf/p1400-update-ref.sh b/t/perf/p1400-update-ref.sh
index ce5ac3ed85..dda8a74866 100755
--- a/t/perf/p1400-update-ref.sh
+++ b/t/perf/p1400-update-ref.sh
@@ -7,13 +7,14 @@ test_description="Tests performance of update-ref"
 test_perf_fresh_repo
 
 test_expect_success "setup" '
-	git init --bare target-repo.git &&
 	test_commit PRE &&
 	test_commit POST &&
-	printf "create refs/heads/%d PRE\n" $(test_seq 1000) >create &&
-	printf "update refs/heads/%d POST PRE\n" $(test_seq 1000) >update &&
-	printf "delete refs/heads/%d POST\n" $(test_seq 1000) >delete &&
-	git update-ref --stdin <create
+	for i in $(test_seq 5000)
+	do
+		printf "start\ncreate refs/heads/%d PRE\ncommit\n" $i &&
+		printf "start\nupdate refs/heads/%d POST PRE\ncommit\n" $i &&
+		printf "start\ndelete refs/heads/%d POST\ncommit\n" $i
+	done >instructions
 '
 
 test_perf "update-ref" '
@@ -26,14 +27,7 @@ test_perf "update-ref" '
 '
 
 test_perf "update-ref --stdin" '
-	git update-ref --stdin <update &&
-	git update-ref --stdin <delete &&
-	git update-ref --stdin <create
-'
-
-test_perf "nonatomic push" '
-	git push ./target-repo.git $(test_seq 1000) &&
-	git push --delete ./target-repo.git $(test_seq 1000)
+	git update-ref --stdin <instructions >/dev/null
 '
 
 test_done
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index 4c01e08551..31b64be521 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -48,17 +48,17 @@ test_expect_success "fail to delete $m with stale ref" '
 	test $B = "$(git show-ref -s --verify $m)"
 '
 test_expect_success "delete $m" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	git update-ref -d $m $B &&
-	test_path_is_missing .git/$m
+	test_must_fail git show-ref --verify -q $m
 '
 
 test_expect_success "delete $m without oldvalue verification" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	git update-ref $m $A &&
 	test $A = $(git show-ref -s --verify $m) &&
 	git update-ref -d $m &&
-	test_path_is_missing .git/$m
+	test_must_fail git show-ref --verify -q $m
 '
 
 test_expect_success "fail to create $n" '
@@ -80,26 +80,26 @@ test_expect_success "fail to delete $m (by HEAD) with stale ref" '
 	test $B = $(git show-ref -s --verify $m)
 '
 test_expect_success "delete $m (by HEAD)" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	git update-ref -d HEAD $B &&
-	test_path_is_missing .git/$m
+	test_must_fail git show-ref --verify -q $m
 '
 
 test_expect_success "deleting current branch adds message to HEAD's log" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	git update-ref $m $A &&
 	git symbolic-ref HEAD $m &&
 	git update-ref -m delete-$m -d $m &&
-	test_path_is_missing .git/$m &&
+	test_must_fail git show-ref --verify -q $m &&
 	grep "delete-$m$" .git/logs/HEAD
 '
 
 test_expect_success "deleting by HEAD adds message to HEAD's log" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	git update-ref $m $A &&
 	git symbolic-ref HEAD $m &&
 	git update-ref -m delete-by-head -d HEAD &&
-	test_path_is_missing .git/$m &&
+	test_must_fail git show-ref --verify -q $m &&
 	grep "delete-by-head$" .git/logs/HEAD
 '
 
@@ -188,31 +188,37 @@ test_expect_success "move $m (by HEAD)" '
 	test $B = $(git show-ref -s --verify $m)
 '
 test_expect_success "delete $m (by HEAD) should remove both packed and loose $m" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	git update-ref -d HEAD $B &&
 	! grep "$m" .git/packed-refs &&
-	test_path_is_missing .git/$m
+	test_must_fail git show-ref --verify -q $m
 '
 
-cp -f .git/HEAD .git/HEAD.orig
 test_expect_success 'delete symref without dereference' '
-	test_when_finished "cp -f .git/HEAD.orig .git/HEAD" &&
-	git update-ref --no-deref -d HEAD &&
-	test_path_is_missing .git/HEAD
+	test_when_finished "git update-ref -d $m" &&
+	echo foo >foo.c &&
+	git add foo.c &&
+	git commit -m foo &&
+	git symbolic-ref SYMREF $m &&
+	git update-ref --no-deref -d SYMREF &&
+	git show-ref --verify -q $m &&
+	test_must_fail git show-ref --verify -q SYMREF &&
+	test_must_fail git symbolic-ref SYMREF
 '
 
 test_expect_success 'delete symref without dereference when the referred ref is packed' '
-	test_when_finished "cp -f .git/HEAD.orig .git/HEAD" &&
+	test_when_finished "git update-ref -d $m" &&
 	echo foo >foo.c &&
 	git add foo.c &&
 	git commit -m foo &&
+	git symbolic-ref SYMREF $m &&
 	git pack-refs --all &&
-	git update-ref --no-deref -d HEAD &&
-	test_path_is_missing .git/HEAD
+	git update-ref --no-deref -d SYMREF &&
+	git show-ref --verify -q $m &&
+	test_must_fail git show-ref --verify -q SYMREF &&
+	test_must_fail git symbolic-ref SYMREF
 '
 
-git update-ref -d $m
-
 test_expect_success 'update-ref -d is not confused by self-reference' '
 	git symbolic-ref refs/heads/self refs/heads/self &&
 	test_when_finished "rm -f .git/refs/heads/self" &&
@@ -226,25 +232,25 @@ test_expect_success 'update-ref --no-deref -d can delete self-reference' '
 	test_when_finished "rm -f .git/refs/heads/self" &&
 	test_path_is_file .git/refs/heads/self &&
 	git update-ref --no-deref -d refs/heads/self &&
-	test_path_is_missing .git/refs/heads/self
+	test_must_fail git show-ref --verify -q refs/heads/self
 '
 
 test_expect_success 'update-ref --no-deref -d can delete reference to bad ref' '
 	>.git/refs/heads/bad &&
 	test_when_finished "rm -f .git/refs/heads/bad" &&
 	git symbolic-ref refs/heads/ref-to-bad refs/heads/bad &&
-	test_when_finished "rm -f .git/refs/heads/ref-to-bad" &&
+	test_when_finished "git update-ref -d refs/heads/ref-to-bad" &&
 	test_path_is_file .git/refs/heads/ref-to-bad &&
 	git update-ref --no-deref -d refs/heads/ref-to-bad &&
-	test_path_is_missing .git/refs/heads/ref-to-bad
+	test_must_fail git show-ref --verify -q refs/heads/ref-to-bad
 '
 
 test_expect_success '(not) create HEAD with old sha1' '
 	test_must_fail git update-ref HEAD $A $B
 '
 test_expect_success "(not) prior created .git/$m" '
-	test_when_finished "rm -f .git/$m" &&
-	test_path_is_missing .git/$m
+	test_when_finished "git update-ref -d $m" &&
+	test_must_fail git show-ref --verify -q $m
 '
 
 test_expect_success 'create HEAD' '
@@ -254,7 +260,7 @@ test_expect_success '(not) change HEAD with wrong SHA1' '
 	test_must_fail git update-ref HEAD $B $Z
 '
 test_expect_success "(not) changed .git/$m" '
-	test_when_finished "rm -f .git/$m" &&
+	test_when_finished "git update-ref -d $m" &&
 	! test $B = $(git show-ref -s --verify $m)
 '
 
@@ -284,8 +290,8 @@ test_expect_success 'empty directory removal' '
 	test_path_is_file .git/refs/heads/d1/d2/r1 &&
 	test_path_is_file .git/logs/refs/heads/d1/d2/r1 &&
 	git branch -d d1/d2/r1 &&
-	test_path_is_missing .git/refs/heads/d1/d2 &&
-	test_path_is_missing .git/logs/refs/heads/d1/d2 &&
+	test_must_fail git show-ref --verify -q refs/heads/d1/d2 &&
+	test_must_fail git show-ref --verify -q logs/refs/heads/d1/d2 &&
 	test_path_is_file .git/refs/heads/d1/r2 &&
 	test_path_is_file .git/logs/refs/heads/d1/r2
 '
@@ -298,8 +304,8 @@ test_expect_success 'symref empty directory removal' '
 	test_path_is_file .git/refs/heads/e1/e2/r1 &&
 	test_path_is_file .git/logs/refs/heads/e1/e2/r1 &&
 	git update-ref -d HEAD &&
-	test_path_is_missing .git/refs/heads/e1/e2 &&
-	test_path_is_missing .git/logs/refs/heads/e1/e2 &&
+	test_must_fail git show-ref --verify -q refs/heads/e1/e2 &&
+	test_must_fail git show-ref --verify -q logs/refs/heads/e1/e2 &&
 	test_path_is_file .git/refs/heads/e1/r2 &&
 	test_path_is_file .git/logs/refs/heads/e1/r2 &&
 	test_path_is_file .git/logs/HEAD
@@ -1388,7 +1394,8 @@ test_expect_success 'handle per-worktree refs in refs/bisect' '
 		git rev-parse refs/bisect/something >../worktree-head &&
 		git for-each-ref | grep refs/bisect/something
 	) &&
-	test_path_is_missing .git/refs/bisect &&
+	git show-ref >actual &&
+	! grep 'refs/bisect' actual &&
 	test_must_fail git rev-parse refs/bisect/something &&
 	git update-ref refs/bisect/something HEAD &&
 	git rev-parse refs/bisect/something >main-head &&
@@ -1500,7 +1507,7 @@ test_expect_success 'transaction can handle abort' '
 	git update-ref --stdin <stdin >actual &&
 	printf "%s: ok\n" start abort >expect &&
 	test_cmp expect actual &&
-	test_path_is_missing .git/$b
+	test_must_fail git show-ref --verify -q $b
 '
 
 test_expect_success 'transaction aborts by default' '
@@ -1511,7 +1518,7 @@ test_expect_success 'transaction aborts by default' '
 	git update-ref --stdin <stdin >actual &&
 	printf "%s: ok\n" start >expect &&
 	test_cmp expect actual &&
-	test_path_is_missing .git/$b
+	test_must_fail git show-ref --verify -q $b
 '
 
 test_expect_success 'transaction with prepare aborts by default' '
@@ -1523,7 +1530,68 @@ test_expect_success 'transaction with prepare aborts by default' '
 	git update-ref --stdin <stdin >actual &&
 	printf "%s: ok\n" start prepare >expect &&
 	test_cmp expect actual &&
-	test_path_is_missing .git/$b
+	test_must_fail git show-ref --verify -q $b
+'
+
+test_expect_success 'transaction can commit multiple times' '
+	cat >stdin <<-EOF &&
+	start
+	create refs/heads/branch-1 $A
+	commit
+	start
+	create refs/heads/branch-2 $B
+	commit
+	EOF
+	git update-ref --stdin <stdin >actual &&
+	printf "%s: ok\n" start commit start commit >expect &&
+	test_cmp expect actual &&
+	echo "$A" >expect &&
+	git rev-parse refs/heads/branch-1 >actual &&
+	test_cmp expect actual &&
+	echo "$B" >expect &&
+	git rev-parse refs/heads/branch-2 >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'transaction can create and delete' '
+	cat >stdin <<-EOF &&
+	start
+	create refs/heads/create-and-delete $A
+	commit
+	start
+	delete refs/heads/create-and-delete $A
+	commit
+	EOF
+	git update-ref --stdin <stdin >actual &&
+	printf "%s: ok\n" start commit start commit >expect &&
+	test_must_fail git show-ref --verify refs/heads/create-and-delete
+'
+
+test_expect_success 'transaction can commit after abort' '
+	cat >stdin <<-EOF &&
+	start
+	create refs/heads/abort $A
+	abort
+	start
+	create refs/heads/abort $A
+	commit
+	EOF
+	git update-ref --stdin <stdin >actual &&
+	printf "%s: ok\n" start abort start commit >expect &&
+	echo "$A" >expect &&
+	git rev-parse refs/heads/abort >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'transaction cannot restart ongoing transaction' '
+	cat >stdin <<-EOF &&
+	start
+	create refs/heads/restart $A
+	start
+	commit
+	EOF
+	test_must_fail git update-ref --stdin <stdin >actual &&
+	test_must_fail git show-ref --verify refs/heads/restart
 '
 
 test_done