Upgrade test infrastructure to PHPUnit 9.6 and PHP 8.3

[mikelittle]

Summary

• Upgrade PHPUnit from 7.5 to ^9.6 (installed 9.6.34) for PHP 8.x support
• Pin humanmade/plugin-tester to wp-6.8-php8.3 tag (from untagged/PHP 7.4)
• Pin minio/minio to RELEASE.2025-01-20T14-49-07Z for reproducibility
• Update phpunit.xml.dist to PHPUnit 9 format (<coverage>/<include> replaces <filter>/<whitelist>)
• Fix PHP 8.2+ dynamic property deprecation and add parent::setUp()/tearDown() calls in tests
• Install missing Imagick JPEG/PDF delegates (libjpeg-turbo, ghostscript, imagemagick-pdf) in test runner
• Add --tmpfs /data to Minio container to avoid 507 Insufficient Storage errors
• Add --ignore-platform-reqs to CI composer install (image's composer binary uses PHP 8.2 internally)
• Update aws/aws-sdk-php from ~3.18 to ^3.366 (picks up latest v3 features and fixes)
• Upgrade Psalm from 3.18.2 to 5.26.1 and psalm-plugin-wordpress from 1.0.1 to 3.1.2
• Psalm is now a fatal check again (was non-fatal due to PHP 8.3 incompatibility)
• Psalm errorLevel set to 2 (previously totallyTyped=true i.e. level 1 in Psalm 3)
• Fix hook registration: use add_filter/remove_filter for filter hooks
• Fix docblock types to match Psalm 5's stricter array shape checking
• Add : void return types to all void methods
• Replace all loose truthy/falsy comparisons with strict type checks
• Add null safety for Key field in stream wrapper options

Test plan

• All 27 tests pass locally with 66 assertions
• Psalm passes with 0 errors at errorLevel 2
• CI pipeline passes on this branch
• No PHPUnit deprecation warnings in output

🤖 Generated with Claude Code

[joehoyle]

Oh does this no-op Psalm? If so, I dont think we should merge this. Any other failing things should be fixed in this PR

[mikelittle]

Oh does this no-op Psalm? If so, I dont think we should merge this. Any other failing things should be fixed in this PR

It looks like there are big changes to accomodate the newer version of psalm.

Here's the impact of upgrading Psalm:

Current state:

• vimeo/psalm 3.18.2 (locked) — requires PHP 7.1+, last release was 2020
• humanmade/psalm-plugin-wordpress ^1.0 — depends on Psalm ^3.11 or ^4.0

What would need to change:

1. Psalm version jump is large — Psalm 3 → 5 (current stable). Psalm 4 was the last to use vimeo/psalm; Psalm 5+ moved to psalm/psalm. This changes the package name entirely.
2. humanmade/psalm-plugin-wordpress ^1.0 — this plugin requires Psalm 3 or 4. It would need to be updated or replaced to work with Psalm 5. Let me check if there's a newer version.
3. psalm.xml config format — attributes like totallyTyped="true" and requireVoidReturnType="false" were deprecated/changed in Psalm 4+ and removed in 5. The config would need rewriting.
4. The Docker image's Phar issue — even with a newer Psalm, PHP 8.3 in the plugin-tester image doesn't have the Phar extension, so Psalm still can't run via /code/vendor/bin/psalm. You'd need to either install Phar in the container or run Psalm via a different entrypoint (php /code/vendor/vimeo/psalm/psalm won't work without Phar either).

In short: It's not just a version bump — it's a package rename (vimeo/psalm → psalm/psalm), a plugin compatibility check (humanmade/psalm-plugin-wordpress), a config file rewrite, and a Docker image fix for the missing Phar extension. It's a meaningful separate task.

I can look to do this though

[joehoyle]

Ok yes I think so! https://github.com/psalm/psalm-plugin-wordpress is compat with Psalm 5, so I think we just need to bump humanmade/psalm-plugin-wordpress to later version too

[mikelittle]

@joehoyle Psalm upgraded to 5.26.1 and fail on error re-instated.
However, the initial run at level 1 produced 133 errors.
So for now, I've dropped to level 4, fixing the 35 errors at that level.
I'll look at the stricter levels too.

[mikelittle]

OK. Level 3 passes now. Shall I keep going?

[joehoyle]

Great, I thikn level 3 is fine, and then we can follow-up to higher level in future prs?

[mikelittle]

I've already got to level 2, and they all look like good fixes. Ready for re-review.
I'll bear in mind level 3 is good for the future.