Social: per-connection message template editor (SOCIAL-451)

[manzoorwanijk]

Fixes SOCIAL-451

Note

Stacked on top of #48560. Easier to review the deltas there: add/social-message-template-editors...add/social-451-per-connection-template-editor

Proposed changes

Surfaces the per-connection template field (server-side wiring landed in #48522) in two places on the Social admin page, both anchored under the row that exposes the Disconnect button so users find it where they already go to manage a connection:

• Inline list — inside each connection's collapsible panel on the Social admin page, below the "Mark the connection as shared" row and above Disconnect.
• Manage Jetpack Social connections modal — under each existing connection's row in the services list. Opens via "Connect an account" → expand a service → see the connection rows.

Both surfaces render the same new ConnectionTemplateEditor, which wraps the shared MessageTemplateEditor from #48560 and auto-saves through updateConnectionById after a 1s debounce. Both stay in sync for free since they read/write through the same connection-data store slice.

Gating (all three required):

• social-message-templates feature flag.
• social-enhanced-publishing paid plan.
• canUserManageConnection capability check.

If any one is missing, the editor is simply hidden — no read-only fallback in this iteration.

Save behaviour mirrors the polish that landed in the SOCIAL-450 PR after review:

• The textarea is not disabled while a save is in flight; the connections endpoint is "last write wins" so concurrent saves resolve fine without freezing the UI on each keystroke pause.
• A lastSentRef guards the useEffect re-sync so a slow save resolving while the user is still typing past the debounce window doesn't clobber their in-progress edits with the just-confirmed earlier value.

Related product discussion/links

Does this pull request change what data or activity we track or use?

No.

Testing instructions

• Connect a site that has both social-message-templates and social-enhanced-publishing features active.
• Go to Jetpack → Social (/wp-admin/admin.php?page=jetpack-social).
• Inline test:
  • Expand any connection's row by clicking the chevron on the right.
  • Confirm a "Custom message for this connection" textarea appears below "Mark the connection as shared" and above Disconnect.
  • Type a custom template; pause; a POST /wp-json/wpcom/v2/publicize/connections/{id} should fire with {"template":"..."} and return 201.
  • Reload the page and re-expand — the saved value hydrates back into the textarea.
• Modal test:
  • Click "Connect an account".
  • Click the chevron next to a service that already has connections (e.g. Bluesky, Facebook).
  • Confirm the same editor renders below each existing connection's "Disconnect" row, with the same auto-save behaviour.
  • Edit the template in the modal; close the modal; expand the same connection in the inline list — value should be in sync without a reload.
• Gate tests:
  • Switch to a user without edit_others_posts (so canUserManageConnection is false for connections owned by others) — the editor should be hidden for those connections.
  • Drop the social-enhanced-publishing feature on the test site — the editor should disappear from both surfaces.
  • Drop social-message-templates — same.

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack), and enable the add/social-451-per-connection-template-editor branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack add/social-451-per-connection-template-editor

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[github-actions]

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Code Coverage Summary

1 file is newly checked for coverage.

File	Coverage
projects/packages/publicize/_inc/components/connection-management/connection-template/index.tsx	20/25 (80.00%) 💚

Full summary · PHP report · JS report

[gmjuhasz]

This works good, the disabling of the whole row while typing feels quite clunky, but we agreed to patch that in a followup p1778070097013599-slack-C0ATW4VK6JH