Twig 3.15 introduces potential bc break for extensions with operators

[marc1706]

The issue is caused by this PR: #4367

Unfortunately I'm currently on the road and don't have much time to debug deeper into the issue, but it essentially comes down to the fact that classes extending \Twig\Extension\AbstractExtension and also implementing operators via getOperators() will have to be updated to precedence_change.

We end up running into this issue with one of our extensions in phpBB after updating twig to the latest version:

Twig\Error\SyntaxError: An exception has been thrown during the compilation of a template ("Undefined array key "precedence_change"") in "define.html".

(see this build: https://github.com/phpbb/phpbb/actions/runs/12332949057/job/34421397543?pr=6761)

As of right now this ends up being a backwards incompatible change and not just a deprecation.

[stof]

Please provide the full stack trace, including the previous exception (which has a more useful location to debug this issue).
The precedence_change is meant to be optional in the config of operators (and most core operators don't provide one).

[rxu]

It can be found following the build link given above, but here it is:

Caused by
PHPUnit\Framework\Error\Warning: Undefined array key "precedence_change"

/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/ExpressionParser.php:152
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/ExpressionParser.php:249
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/ExpressionParser.php:103
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/TokenParser/IfTokenParser.php:39
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Parser.php:202
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Parser.php:95
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Environment.php:539
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Environment.php:567
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Environment.php:395
/home/runner/work/phpbb/phpbb/phpBB/phpbb/template/twig/environment.php:284
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Environment.php:357
/home/runner/work/phpbb/phpbb/phpBB/vendor/twig/twig/src/Environment.php:320
/home/runner/work/phpbb/phpbb/phpBB/phpbb/template/twig/environment.php:230
/home/runner/work/phpbb/phpbb/phpBB/phpbb/template/twig/environment.php:200
/home/runner/work/phpbb/phpbb/phpBB/phpbb/template/twig/twig.php:293
/home/runner/work/phpbb/phpbb/tests/template/template_test_case.php:43
/home/runner/work/phpbb/phpbb/tests/template/template_test_case.php:162
/home/runner/work/phpbb/phpbb/tests/template/template_test.php:556

At the top of the trace, it seems to be this line

Twig/src/ExpressionParser.php

Line 152 in 918f52e

$change = $this->unaryOperators[$target]['precedence_change'];

[stof]

do you have a Twig template triggering the issue (ideally a minimal one) ?

[rxu]

It's as simple as this:

{% if !variable_does_not_exist %}
{{ 'Get Undefined array key "precedence_change" PHP Warning' }}
{% endif %}

[fabpot]

It's as simple as this:

{% if !variable_does_not_exist %}
{{ 'Get Undefined array key "precedence_change" PHP Warning' }}
{% endif %}

As ! is not supported by Twig, I suppose it's defined somewhere. Can you share how it's defined?

[rxu]

Sure. It's here https://github.com/phpbb/phpbb/blob/1096b094cb54043c682e85dd8e34daa4e98f9891/phpBB/phpbb/template/twig/extension.php#L111