Treat the duplicate message id send error as a successful delivery

[andremion]

Goal

When a message send is retried after its response was lost (for example, the connection drops before the ack is processed), the backend rejects the retry with a 400 input error: code 4, "a message with ID x already exists". The message was in fact delivered by the first attempt, but the SDK marked it as FAILED_PERMANENTLY. The user then sees a delivered message as failed, and a manual resend fails again with the same error, so the message can never leave the failed state. The iOS SDK already treats this rejection as a successful send.

This is the SDK side of the fix for the message list crash found in the e2e nightly (test_userAddsReactionWhileOffline): the mock server used to accept the duplicate send and store a second copy with the same id, and the channel query response then crashed the Compose message list with a duplicate LazyColumn key. The mock server now mirrors the backend rejection (see GetStream/stream-chat-test-mock-server#51), which makes this SDK path reachable in e2e.

Resolves AND-1320

Implementation

• Added an internal Error.isDuplicateMessageError() extension that detects the backend rejection: Error.NetworkError with server error code 4 (ChatErrorCode.VALIDATION_ERROR) and a message containing "already exists". This is the same detection the iOS SDK uses in MessageRepository.
• SendMessageListenerState and SendMessageListenerDatabase now route this failure to their existing success handling, so the message is stored with SyncStatus.COMPLETED instead of FAILED_PERMANENTLY.

Testing

Unit tests: new cases in SendMessageListenerStateTest and SendMessageListenerDatabaseTest cover the duplicate rejection (message marked as completed) and a different validation error (message still marked as failed permanently).

Manual steps:

1. Open a channel and send a message, then cut connectivity immediately so the send response is lost (on an emulator: adb shell svc wifi disable and adb shell svc data disable right after tapping send). The message must stay in the pending state.
2. Restore connectivity and wait for the reconnect sync to retry the send.
3. Before this change, the retried message could show the failed indicator even though the first attempt delivered it. After this change, it shows as sent.

E2e: test_userAddsReactionWhileOffline exercises this flow when the send races the offline switch, together with the mock server PR above. Verified locally against the updated mock server (test passes; the duplicate send returns 400 and the message list contains the message once).

Summary by CodeRabbit

• Bug Fixes

  • Duplicate message-send responses are now treated as successful, preventing messages from being incorrectly marked as permanently failed.
  • Messages affected by duplicate IDs are stored with a completed sync status.
  • Other validation errors continue to be handled as permanent failures.

• Tests

  • Added coverage for duplicate message IDs and other validation-error scenarios.

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled, or the PR is bot-authored.
• An issue is linked (Linear ticket or GitHub issue), or the PR is bot-authored.

🎉 Great job! This PR is ready for review.

[andremion]

@CodeRabbit review

[coderabbitai]

✅ Action performed

Review finished.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[coderabbitai]

Walkthrough

Adds duplicate-message error classification and routes matching send failures through successful completion in both offline database and state listeners, with tests covering duplicate and other validation errors.

Changes

Duplicate message handling

Layer / File(s)	Summary
Duplicate error classification stream-chat-android-client/src/main/java/io/getstream/chat/android/client/errors/ErrorExtensions.kt	Adds an internal check for network validation errors whose message contains "already exists".
Send result routing and validation stream-chat-android-client/src/main/java/io/getstream/chat/android/client/internal/.../SendMessageListener*.kt, stream-chat-android-client/src/test/java/io/getstream/chat/android/client/internal/.../SendMessageListener*Test.kt	Routes duplicate-message failures through success handling and verifies COMPLETED versus FAILED_PERMANENTLY persistence outcomes.

Estimated code review effort: 2 (Simple) | ~10 minutes

Sequence Diagram(s)

sequenceDiagram
  participant SendMessageListener
  participant ErrorClassifier
  participant SendHandler
  SendMessageListener->>ErrorClassifier: classify failed send error
  ErrorClassifier-->>SendMessageListener: duplicate or non-duplicate
  SendMessageListener->>SendHandler: use success or failure handling

Loading

Poem

I’m a rabbit with messages bright,
Duplicate IDs now land just right.
Success paws stamp “completed” with cheer,
Other failures stay crystal clear.
Hop, hop—validated paths appear!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	Concise and accurately summarizes the main fix: duplicate message ID send errors are treated as successful deliveries.
Description check	✅ Passed	Includes Goal, Implementation, and Testing, covering the required substance; only non-critical template sections like UI Changes, Checklist, and GIF are missing.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch andrerego/and-1320-message-list-crashes-with-a-duplicate-lazycolumn-key-when-a

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	5.95 MB	5.95 MB	0.00 MB	🟢
stream-chat-android-ui-components	11.22 MB	11.22 MB	0.00 MB	🟢
stream-chat-android-compose	12.70 MB	12.70 MB	0.00 MB	🟢

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
88.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[stream-public-bot]

🚀 Available in v7.7.0