Exclude tests and development files from Composer dist via .gitattributes

[hosni]

Add a .gitattributes file so development-only paths are marked with export-ignore. When users install via Composer’s default dist archives, they get a smaller package without the test suite and related tooling/config, while those files remain in the Git repository for development and CI.
Paths excluded from dist exports include:

• tests/
• .github/
• tooling/config (e.g. phpunit.xml, phpstan.dist.neon, .php-cs-fixer.php)
• contributor/docs that aren’t needed at runtime (CONTRIBUTING.md, TODO.md, etc.)
  This does not change runtime behaviour. Tests are unchanged and still available in the source repo / when installing with --prefer-source.
  No new behavioural tests or README updates are needed for this packaging-only change.

[cviebrock]

Thanks @hosni ... interesting!

Is this any different than defining those exclusions in composer.json with an archive.exclude entry?

[hosni]

Yes, there is.
archive.exclude only affects archives created with composer archive, whereas export-ignore is honored by git archive, which GitHub uses to generate the source ZIPs that Composer typically downloads as dist packages. So for GitHub-hosted packages, .gitattributes is what actually reduces the size of the package users receive.

[cviebrock]

Nice. Great addition to the packages ... thanks @hosni !

[cviebrock]

Version 13.0.1 includes this now, and I can confirm from the zip archive it works 😉 .

[hosni]

@cviebrock Thank you for your great package! 🫶

This is the difference between archive size of 13.0.0 and 13.0.1, exactly 300KB 😄