[MAINT] Github Actions Reunification - `check-extension`

[damienwebdev]

Workflows: check-extension.yaml + _internal_check_extension.yaml

Status: ➕ Graycore-only — evaluate for porting
Files: .github/workflows/check-extension.yaml, .github/workflows/_internal_check_extension.yaml

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PR context

The graycore remove_cache_arg branch modifies check-extension.yaml:

• Removes COMPOSER_MIRROR_PATH_REPOS: 1 from composer install steps
• Replaces the coding-standard action call with inlined steps (get-composer-version → semver-compare → allow-plugins → composer require → phpcs config-set → phpcs run) — this brings it in line with how graycore is removing the built-in PHP-setup from the coding-standard action
• Removes the release-please guard from _internal_check_extension.yaml

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What these workflows do

check-extension.yaml is a reusable workflow that consumers call to check a Magento extension: runs coding standard, integration tests, and verifies installability. _internal_check_extension.yaml is the internal self-test.

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Dependents

No mage-os dependents yet. In graycore, external repos call check-extension.yaml directly.

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Decision required

Should these workflows be ported to the mage-os fork?

Arguments for porting:

• Provides a complete, batteries-included experience for Mage-OS extension authors
• Mirrors the value proposition of the graycore library

Arguments against porting:

• Mage-OS fork has its own equivalent workflows (full-integration-tests.yaml, nx-integration-tests.yml)
• May require adaptation for Mage-OS-specific tooling (warden, nx)

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Changes needed if porting (based on graycore remove_cache_arg target state)

1. Copy check-extension.yaml from graycore remove_cache_arg branch (not main — get the updated version with inlined coding standard steps and no COMPOSER_MIRROR_PATH_REPOS)
2. Copy _internal_check_extension.yaml from graycore remove_cache_arg branch (release-please guard already removed)
3. Update all action refs from graycoreio/github-actions-magento2/...@main to mage-os/github-actions/...@main
4. Update token secret names to mage-os equivalents (e.g. MAGE_OS_CI_TOKEN)
5. Verify dependencies — get-composer-version, semver-compare, setup-magento, integration.yaml must be updated per their respective plans before enabling this workflow