[T3352] FIX: guard letter submit against double-click race

[Danielgergely]

-FIX: Guard _onSubmitLetter against double submission + error.

[greptile-apps]

Confidence Score: 4/5

T-Rex Logs

What T-Rex did

• T-Rex produced a proof for the posted P1 finding and linked it to the corresponding review comment for finding details.
• T-Rex validated the in-flight create_generator calls by reproducing two calls, send and save_draft, both using _isSubmitting: true and an empty generator_id, in the file my_compassion/static/src/js/my2_new_letter.js:316-330, where autosave lacks an _isSubmitting/shared-operation guard and interacts with the submit guard at lines 63-67.

_{Ran code and verified through T-Rex}

Comments Outside Diff (2)

1. my_compassion/static/src/js/my2_new_letter.js, line 316-330 (link)

   Autosave bypasses submission lock

   When a user edits a new letter and submits before the pending five-second autosave fires, _autoSaveDraft bypasses _isSubmitting and calls _createGenerator concurrently. Both requests can read the same empty or stale generator_id, causing duplicate generator records for a new letter or conflicting last-write-wins updates to an existing draft.

2. General comment

   Autosave can race an active letter submission

   • Bug
     • A five-second autosave timer can invoke _autoSaveDraft while _onSubmitLetter is awaiting _createGenerator. Autosave does not inspect _isSubmitting or share a mutual-exclusion mechanism, so it sends another create_generator RPC.
   • Cause
     • _isSubmitting is set and checked only by _onSubmitLetter; _autoSaveDraft independently collects the form snapshot and calls _createGenerator. The form input is updated with the server generator ID only after an RPC resolves.
   • Fix
     • Coordinate autosave and submission with a shared in-flight guard/lock (or skip/cancel autosave while _isSubmitting is true) and ensure a pending autosave is cancelled or deferred when submission begins.

   _{Ran code and verified through T-Rex}

_{Reviews (1): Last reviewed commit: "[T3352] FIX: guard letter submit against..." | Re-trigger Greptile}