[PHP 7.4] Add coalesce equal ??=

[TomasVotruba]

Adds ??= support php/php-src#3747

Tests are failing.

It looks like it's not possible to add it. Probably needs to wait for T_COALESCE_EQUAL token, or not?

[nikic]

Yes, it should use T_COALESCE_EQUAL. If we run on a PHP version that does not have it, then we need to emulate it in Lexer\Emulative, by combining a T_COALESCE and a '=' token into a T_COALESCE_ASSIGN token.

[TomasVotruba]

Thanks for navigation. I dig through history and blame and tried to inspire at: 251e689

Emulative parsers seems to work, but grammer still looks broken. Any clue?

[nikic]

Not sure what's up with the test failure. Token 392 on PHP 7.1 is E_ERROR, but I don't really see why it would occur in this situation.

[TomasVotruba]

Thanks for review, I'll integrate it and see it helped with the error.

[TomasVotruba]

Now the parser is rebuild without error 👍

Yet the error still remains:

1) PhpParser\PrettyPrinterTest::testPrettyPrint with data set "var/www/PHP-Parser/test/code/prettyPrinter/expr/operators_php7.test#0" ('Basic operators (/var/www/PHP....test)', '<?php\n\n$a ??= $c;', '$a ??= $c;', 'php7')
RangeException: The lexer returned an invalid token (id=281, value=??=)

Test fixture - operators_php7.test:

Basic operators
-----
<?php

$a ??= $c;
-----
!!php7
$a ??= $c;

[TomasVotruba]

Any tips what tests should I add?

[nikic]

Okay, I believe this issue here is that the token is not used in the PHP 5 parser and thus gets dropped from the translation table. It would be fine if you just add support for ??= to the PHP 5 parser as well.

One thing that's missing here is a parser test for ??=. If ??= is supported in the PHP 5 parser as well, you can just add it into test/code/parser/expr/assign.test.

[TomasVotruba]

It would be fine if you just add support for ??= to the PHP 5 parser as well.

Works like a charm!

One thing that's missing here is a parser test for ??=. If ??= is supported in the PHP 5 parser as well, you can just add it into test/code/parser/expr/assign.test.

👍 I'm on it

[nikic]

Merged as 9de9682. Thanks :)

[TomasVotruba]

👍 Thank you

[TomasVotruba]

Any ETA for release of this? I'd love to test in Rector and real code to demonstrace PHP 5.3 → 7.4 upgrade

[nikic]

Done: https://github.com/nikic/PHP-Parser/releases/tag/v4.2.1

[TomasVotruba]

Wow! Thank you ❤️