Choose which post types publish to AT Protocol

[pfefferle]

Proposed changes

• New Post types field in Settings → ATmosphere with a checkbox per public post type. Stored as atmosphere_support_post_types (default ['post']).
• Plugins and themes can opt their custom post types in via the WordPress-canonical \add_post_type_support( 'book', 'atmosphere' ) — picked up automatically.
• Replaces Backfill::syncable_post_types() with Atmosphere\Post_Types + bridge functions Atmosphere\get_supported_post_types() and Atmosphere\is_supported_post_type().
• atmosphere_syncable_post_types filter preserved; now runs after the option and native opt-ins are merged so callers can add or remove from either source.

Other information

• Have you written new tests for your changes, if applicable?

Testing instructions

1. Visit Settings → ATmosphere. Confirm a new Post types field appears in the Publishing section with a checkbox per public post type. Posts is checked by default.
2. Check Pages, save, edit any page. The ATmosphere meta box should appear.
3. Uncheck everything, save, and confirm no meta box renders on any post-edit screen.
4. In a small test plugin, add add_post_type_support( 'book', 'atmosphere' ); for a custom book CPT — confirm Atmosphere\get_supported_post_types() includes it even when the option is empty.
5. composer lint and npm run env-test should pass.

[Copilot]

Pull request overview

Adds a configurable “supported post types” mechanism so ATmosphere publishing can be enabled per post type via Settings, WordPress-native add_post_type_support( ..., 'atmosphere' ), and the existing atmosphere_syncable_post_types filter.

Changes:

• Introduces Atmosphere\Post_Types plus helper functions Atmosphere\get_supported_post_types() / Atmosphere\is_supported_post_type().
• Adds a new settings option (atmosphere_support_post_types) and UI field (checkboxes for public post types).
• Replaces uses of Backfill::syncable_post_types() with the new resolver and adds PHPUnit coverage.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
tests/phpunit/tests/class-test-post-types.php	Adds tests for option-driven, native-support, and filter-driven supported post types.
includes/wp-admin/class-admin.php	Registers the new option and renders the settings UI; uses supported types for meta box registration.
includes/functions.php	Adds bridge helper functions for supported post type queries.
includes/class-post-types.php	Implements supported post type resolution + sanitization.
includes/class-backfill.php	Switches backfill targeting to the new supported post types list.
includes/class-atmosphere.php	Gates frontend link output, preview, and lifecycle hooks using is_supported_post_type().
.github/changelog/add-post-type-support	Changelog entry describing the new capability.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

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[kraftbj]

Combined review comments from the full PR pass, including the FOSSE-specific concerns and the remaining existing review concerns.

[pfefferle]

@kraftbj it was not meant to fix what you fixed with your PR already, this was simply meant to extract the functionality to a dedicated class/function instead of a weird artifact that lives in the Backfill structure (which I am not even sure we need). I am happy to point the PR to your branch instead or directly work on your branch.

[pfefferle]

I rebased it to your pr.

[kraftbj]

Verified 0685c47 against all eight unresolved review threads and resolved them. Summary of what I checked against the code at that SHA:

• P1 cleanup must bypass current allowlist (both threads): on_before_delete() no longer gates on is_supported_post_type() and only checks for existing TIDs; on_status_change() restricts the support check to the publish/update branches and lets unpublish defer to TID metadata. PR 41 is rebased onto fix/cleanup-gate-split (merge-base matches that branch's head), so this depends on PR 38 landing first.
• P2 cron publish should re-check support (both threads): register_async_hooks() re-checks is_supported_post_type( $post->post_type ) inside both the atmosphere_publish_post and atmosphere_update_post callbacks. The atmosphere_delete_post callback intentionally omits the check so cleanup keeps running.
• P3 settings UI shows filtered-out types as enabled (both threads): render_support_post_types_field() now distinguishes $is_external and $is_filtered_out and renders "Disabled by another plugin or theme — this post type will not be published." for the saved-but-filtered case.
• P3 normalize saved post type option: Post_Types::sanitize() drops non-strings, runs sanitize_key, filters empties, and dedupes via array_unique before intersecting against public post types.
• P3 avoid resolving support once per backfill ID: Backfill::handle_batch() resolves get_supported_post_types() once before the loop and uses in_array( $post->post_type, $supported, true ) per ID.

All eight threads resolved; ready for formal approval.