[php][ext] Support NULL values conversion

[FabioBatSilva]

• Handle NULL values in the PHP extension's conversion functions.
• Tests that verify the behavior of converting supported types.

Should fix : #20000

[haberman]

I just left a comment on #20000, I think we generally don't want to support $msg->setFoo(null).

[github-actions]

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[FabioBatSilva]

Please don't dismiss it.
PR is still relevant, waiting for the maintainers.

[FabioBatSilva]

I just left a comment on #20000, I think we generally don't want to support $msg->setFoo(null).

#20649 (comment)

[github-actions]

We triage inactive PRs and issues in order to make it easier to find active work. If this PR should remain active, please add a comment.

This PR is labeled inactive because the last activity was over 90 days ago. This PR will be closed and archived after 14 additional days without activity.

[FabioBatSilva]

PR is still relevant, waiting for the maintainers. 😞

[JasonLunn]

Marking this issue blocked rather than untriaged since the discussion in #20000 seems to be centered around introducing an (as of yet unimplemented) breaking change in the 2027 release

[bshaffer]

@JasonLunn I believe this can be closed. From the linked issue:

if we instead add the first-class type on it public function setMyField(string $var) the behavior is that it will coerce to string before our logic runs. Our minimum PHP version support is high enough now that it looks like we should be able to do it.

I've added types to setters in #25296, so the discussed solution has been implemented.