Bug #80260 [PATCH]: PDO::inTransaction() returns false when inside transaction

From: Date: Tue, 20 Oct 2020 09:48:20 +0000
Subject: Bug #80260 [PATCH]: PDO::inTransaction() returns false when inside transaction
References: 1  Groups: php.bugs 
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Edit report at https://bugs.php.net/bug.php?id=80260&edit=1

 ID:                 80260
 Patch added by:     nikic@php.net
 Reported by:        corey dot taylor dot fl at gmail dot com
 Summary:            PDO::inTransaction() returns false when inside
                     transaction
 Status:             Open
 Type:               Bug
 Package:            PDO MySQL
 PHP Version:        8.0.0RC2
 Block user comment: N
 Private report:     N

 New Comment:

The following pull request has been associated:

Patch Name: Fix inconsistency in PDO transaction state
On GitHub:  https://github.com/php/php-src/pull/6355
Patch:      https://github.com/php/php-src/pull/6355.patch


Previous Comments:
------------------------------------------------------------------------
[2020-10-20 08:54:55] corey dot taylor dot fl at gmail dot com

If this turns out to be *entirely* due to DDL transactions - are you saying that
PDO::inTransaction() won't support them?

------------------------------------------------------------------------
[2020-10-20 08:50:46] corey dot taylor dot fl at gmail dot com

I spent some time trying to narrow down the scenarios as you mentioned. It's difficult when it
happens in a complex test harness.

Yes, the initial failure were showing up from a DDL transaction. I thought the same thing here that
maybe there was a sync issue. However, the mysql instance clearly thinks the transaction is ok since
it's waiting on a commit.

After working on moving the DDL that fails out of the transactions and only putting inserts into the
transaction, that initial failure stopped, but the same error occurs further down our test suite. It
is possible there is a completely unrelated transaction with DDL in it before this failure, but so
far I haven't found it. The test suite really only runs DDL in one place.

We don't mix manual and PDO transactions. Everything be through beginTransaction, commit and
rollback.

------------------------------------------------------------------------
[2020-10-20 08:44:02] nikic@php.net

Okay, next guess: You are running a DDL query inside a transaction, which (for MySQL) will cause an
automatic commit, even outside autocommit mode
(https://dev.mysql.com/doc/refman/8.0/en/implicit-commit.html). That means inTransaction() reports
false, but PDO still thinks its inside a transaction.

Does that sound plausible?

------------------------------------------------------------------------
[2020-10-20 08:40:02] nikic@php.net

Do you mix usage of PDO transaction APIs with transaction queries? Like, call
PDO::beginTransaction() and then issue a manual COMMIT?

PDO's internal state could go out of sync in such a case. We should probably make PDO
internally use the same mechanism as PDO::inTransaction() to determine whether it is inside a
transaction.

However, I'm not sure this is really the case you're seeing, I suspect that is another
problem here.

------------------------------------------------------------------------
[2020-10-20 03:58:18] corey dot taylor dot fl at gmail dot com

The environment we see this on is ubuntu 16.04 (xenial) travis-ci with default mysql 5.7 and php
nightly builds. There are no custom pdo configurations.

------------------------------------------------------------------------


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the rest of the comments, please view the bug report online at

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