chore(platform): clean up sub-threads when parent thread is deleted

[larryro]

Summary

• When a chat thread is deleted (archived), any sub-threads referenced in the thread summary are now cleaned up asynchronously via a scheduled internal mutation
• Adds parseSubThreadIds helper to extract sub-thread IDs from the thread summary JSON
• Adds cleanupOrphanedSubThreads internal mutation that archives active sub-threads

Test plan

• Unit tests for parseSubThreadIds covering edge cases (undefined, empty, invalid JSON, valid data)
• Unit tests for deleteChatThread verifying sub-thread cleanup is scheduled only when sub-threads exist
• Verify in dev that deleting a thread with sub-threads archives all sub-threads

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Summary by CodeRabbit

Release Notes

• Improvements
  • Enhanced chat thread deletion to automatically clean up orphaned sub-threads when a parent thread is deleted, ensuring proper archiving of related conversations and maintaining thread hierarchy consistency.

[coderabbitai]

📝 Walkthrough

Walkthrough

The changes implement sub-thread cleanup functionality triggered when a parent thread is deleted. A new parseSubThreadIds function extracts sub-thread identifiers from thread summary JSON data. The deleteChatThread workflow is updated to fetch the parent thread, parse any sub-thread IDs, and conditionally schedule an async cleanup mutation if sub-threads exist. A new internal mutation cleanupOrphanedSubThreads iterates through provided sub-thread IDs, fetches each sub-thread, and archives those with active status. Comprehensive unit tests cover edge cases including missing data, invalid JSON, absent sub-threads, and successful cleanup execution with verification of scheduling and mutation invocation.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related issues

• chore: implement sub-thread cleanup for parent thread deletion #73: This PR directly implements the code-level sub-thread cleanup mechanism (parsing subThread IDs from summaries, scheduling async cleanup, and executing the cleanupOrphanedSubThreads mutation) that addresses the issue's requirement for sub-thread cleanup on parent thread deletion.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: implementing cleanup of sub-threads when a parent thread is deleted, which is the core functionality added across all modified files.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch chore/73-sub-thread-cleanup

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@services/platform/convex/threads/delete_chat_thread.ts`:
- Around line 10-17: The code calls components.agent.threads.updateThread
unconditionally after fetching the thread with
components.agent.threads.getThread; add an explicit guard on the fetched thread
(e.g., check if thread is null/undefined) and skip or return early (or throw a
404) instead of calling updateThread when no thread exists; ensure you reference
the same threadId and preserve the existing patch { status: 'archived' }
behavior when the thread is present.

[greptile-apps]

Greptile Summary

This PR adds sub-thread cleanup when a parent chat thread is deleted (archived). The deleteChatThread function now queries the thread's summary to extract sub-thread IDs, and if any exist, schedules an asynchronous cleanupOrphanedSubThreads internal mutation to archive them. A parseSubThreadIds helper provides defensive JSON parsing with proper error handling.

• Adds getThread query in deleteChatThread to read the parent thread's summary before archiving
• Introduces parseSubThreadIds to safely extract sub-thread IDs from the summary JSON (handles undefined, empty, invalid JSON, and non-string values)
• Adds cleanupOrphanedSubThreads internal mutation that sequentially checks and archives active sub-threads
• Sub-thread cleanup is scheduled via ctx.scheduler.runAfter(0, ...) for async execution outside the parent transaction
• Includes comprehensive unit tests for the parsing helper and delete function behavior

Confidence Score: 4/5

• This PR is safe to merge with minimal risk — the changes are well-structured, defensive, and the async cleanup approach avoids impacting parent thread deletion.
• Score reflects clean implementation with defensive error handling, good test coverage of the parsing logic and deletion flow, and appropriate use of async scheduling to isolate cleanup from the main operation. Deducted one point because the cleanupOrphanedSubThreads mutation itself lacks direct unit tests, and the parent thread is archived even when getThread returns null (though this is pre-existing behavior).
• No files require special attention, though services/platform/convex/threads/internal_mutations.ts could benefit from direct unit tests for the cleanupOrphanedSubThreads handler.

Important Files Changed

Filename	Overview
services/platform/convex/threads/delete_chat_thread.ts	Adds getThread query before archiving to extract sub-thread IDs from summary, then schedules async cleanup. Defensive parsing with try/catch. Archives parent even when thread not found (pre-existing behavior).
services/platform/convex/threads/internal_mutations.ts	Adds cleanupOrphanedSubThreads internal mutation that iterates sub-thread IDs, checks each is active, and archives them sequentially. Includes logging of archived count.
services/platform/convex/threads/delete_chat_thread.test.ts	New test file with thorough unit tests for parseSubThreadIds (7 edge cases) and deleteChatThread (4 scenarios covering archive, no sub-threads, with sub-threads, and missing thread). No tests for the cleanupOrphanedSubThreads mutation itself.

Sequence Diagram

sequenceDiagram
    participant Client
    participant deleteChatThread
    participant AgentSDK as Agent SDK (Threads)
    participant Scheduler
    participant cleanupMutation as cleanupOrphanedSubThreads

    Client->>deleteChatThread: delete(threadId)
    deleteChatThread->>AgentSDK: getThread(threadId)
    AgentSDK-->>deleteChatThread: thread (with summary)
    deleteChatThread->>AgentSDK: updateThread(archived)
    deleteChatThread->>deleteChatThread: parseSubThreadIds(summary)

    alt Sub-threads exist
        deleteChatThread->>Scheduler: runAfter(0, cleanupOrphanedSubThreads)
        Scheduler->>cleanupMutation: execute(parentThreadId, subThreadIds)
        loop For each subThreadId
            cleanupMutation->>AgentSDK: getThread(subThreadId)
            AgentSDK-->>cleanupMutation: subThread
            alt subThread is active
                cleanupMutation->>AgentSDK: updateThread(archived)
            end
        end
        cleanupMutation-->>Scheduler: { archivedCount }
    end

    deleteChatThread-->>Client: void

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_{Last reviewed commit: cadc6b6}

[greptile-apps]

_{3 files reviewed, 1 comment}

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