The remove-background route's catch block turned every throw from removeImageBackground into a 502 "the background-removal service did not answer". But removeImageBackground also throws for an unrecognised file extension (a legacy .jpeg), for a file missing from the uploads volume, and when REMBG_URL is not set at all — none of which involve contacting the sidecar. The admin was told to retry a service that was never reached, while the real reason existed only in the server log.
Added SidecarRequestError in rembgClient.ts, following the NoOriginalToRestoreError pattern already in backgroundRemoval.ts. It is thrown only for failures that happen after actually attempting to reach the sidecar: the fetch call itself throwing (now wrapped in a try/catch, covering unreachable and timed-out), a non-2xx response, or a response that is not a PNG. It is deliberately not thrown for "REMBG_URL is not set", since that path never attempts contact at all.
The remove-background handler now checks err instanceof SidecarRequestError before answering 502; everything else answers 500 with a message that says what actually went wrong.
Added a unit test pairing (rembgClient.test.ts) asserting the sidecar-contacted failures are SidecarRequestError and the unconfigured case is not, and an integration test (adminItemDrafts.integration.test.ts) proving a missing upload file answers something other than 502 with a message that does not claim the service did not answer.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
bermudalambandClaude Opus 5
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