[rquidute]

Summary

Part of the fix for #1062: THCLI reports a WebSocket error after successfully uploading a manual test log (e.g. TC-CADMIN-1.17), even though the upload itself completed.

This is the CLI-side complement to the backend fix in certification-tool-backend#343, which batches log-line broadcasts during upload processing to avoid stalling the backend's event loop in the first place. This PR makes the CLI resilient to the case where the WebSocket connection still gets dropped (e.g. on very large files, slower networks, etc.) after the upload has already succeeded.

Root cause

In __upload_file_and_send_response, both the HTTP file upload and the subsequent _send_prompt_response() WebSocket call were wrapped in the same try/except block. When the backend's event loop was busy handling the flood of log broadcasts triggered by processing a large uploaded file, the WebSocket's keepalive ping/pong could time out and the connection would be dropped after the upload had already succeeded but before the CLI could send the "SUCCESS" prompt response. That ConnectionClosedError was caught by the generic except Exception handler and echoed as ❌ Unexpected error uploading file: no close frame received or sent — misleading, since the file was already uploaded.

Fix

• Wrap only the _send_prompt_response() call (not the upload) in a dedicated except websockets.exceptions.ConnectionClosed handler.
• Report this case as a distinct warning that makes clear the file was already uploaded successfully, instead of falling into the same "unexpected error" branch used for actual upload failures.
• Actual upload failures (network errors, HTTP errors, other exceptions during the upload itself) are unaffected and still reported as errors.

Testing

Added unit tests in tests/test_run/test_prompt_manager.py covering:

• Successful upload + successful prompt response.
• Successful upload where the WebSocket is closed before the response can be sent (now reported as a warning, not an error).
• An actual upload failure (still reported as an error, unchanged behavior).

Note: this sandbox's local test venv has no network access to install pytest/httpx/websockets, so I validated the test logic and the fixed function's control flow via a standalone script (traced through the try/except structure with stubs) rather than via pytest directly. Please re-run the full suite in CI/your dev environment to confirm.

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[gemini-code-assist]

Code Review

This pull request decouples the file upload from sending the prompt response confirmation in __upload_file_and_send_response to prevent WebSocket timeouts from being misreported as upload failures, and adds corresponding unit tests. The reviewer suggested catching a broader Exception instead of only websockets.exceptions.ConnectionClosed when sending the confirmation to ensure any post-upload failure is correctly reported as a warning rather than an upload error.