[yogeshbhutkar]

What, Why, and How?

Closes #1138

While testing the Content Translation experiment, I found that toggling "Show template" during a translation doesn't stop it, but none of the remaining results are applied. Switching the editor view recreates the post's blocks with new client IDs. The translation keeps sending requests for the old IDs, and each result is silently dropped because those blocks no longer exist, so the requests and tokens are wasted. The same happens when a block is deleted or transformed mid-translation, and in every case the dropped blocks were still counted as translated.

Rather than watching for specific triggers like the rendering mode, this PR checks whether each block still exists:

• Before sending a batch, blocks that no longer exist are dropped, so no requests are spent on them. After a template toggle, every remaining batch is empty and the translation finishes on its own.
• Before applying a result, the block is checked again in case it was removed while its request was in flight.
• Removed blocks are counted separately from failures, so they aren't offered for retry and don't inflate the progress count.

Also, Generate Editorial Notes seems to rely on block client IDs and may have the same problem (untested as of now). That should be handled in a separate PR.

Use of AI Tools

AI assistance: Yes
Tool(s): Claude Code
Model(s): Opus 5.5
Used for: Reviewing the code and stress testing the changes.

Screencast

screencast.mov

Changelog Entry

Fixed - Skip blocks that are removed or replaced mid-translation in Content Translation.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.17%. Comparing base (26322c3) to head (b716658).

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #1137   +/-   ##
==========================================
  Coverage      82.17%   82.17%           
  Complexity      3399     3399           
==========================================
  Files            136      136           
  Lines          13187    13187           
==========================================
  Hits           10837    10837           
  Misses          2350     2350           

Flag	Coverage Δ
unit	82.17% <ø> (ø)

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[github-actions]

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Co-authored-by: yogeshbhutkar <yogeshbhutkar@git.wordpress.org>
Co-authored-by: dkotter <dkotter@git.wordpress.org>

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