Fix #71868: Environment variables with no value are filtered out by proc_open()

[nradchenko]

Remove empty value check from _php_array_to_envp (introduced in 7e92f63)

[cmb69]

Thank you for the PR! However, the legit test failures show that this change might break existing scripts and applications, so I'm generally reluctant to change any of the stable PHP versions in this regard. It is even debatable whether the current behavior is a bug or a feature, since programs are generally free to treat empty environment variables and unset environment variables the same. Maybe it is a good idea to write to the internals mailing list to ask for thoughts on this change.

[nradchenko]

Good point.

It is even debatable whether the current behavior is a bug or a feature

I'm not 100% sure about this, so it's definitely needs more investigation. I'm aware that PHP test system uses proc_open, so it might need some tuning too.

Maybe it is a good idea to write to the internals mailing list to ask for thoughts on this change

Thanks for the hint! I'll also try to add a note about the current behavior to the documentation.

Can we leave this draft PR open? @cmb69

[cmb69]

Can we leave this draft PR open?

Sure. :)

[beberlei]

An alternative could be to make this behavior opt-in with a new options flag pass_empty_environment_variables or something along these lines.

[crrodriguez]

Empty values on the enviroment are ok.. I see valid usescases.
This one of the other bugs I did not fix in PR #7933 .

Other issues remain like
$env = array('=' => 'aeiou', '\0oops' => '\0oops');
which is a completely invalid environment to pass but there is no error.

• having an equal sign in the environment variable name is malformed
• having NULL bytes in both the name and value is malformed.

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