fix: LiveQuery subscriptions leak when a client reuses a subscribe requestId

[mtrezza]

Issue

Parse Server LiveQuery accepts multiple subscribe frames from the same WebSocket client that reuse a single requestId. The client-side subscription metadata is keyed only by requestId, so each duplicate subscribe overwrites the previous entry while the previously created subscription remains in the server-wide subscriptions map. Disconnect cleanup only walks the surviving client metadata, so the orphaned subscriptions are never removed — they persist for the lifetime of the process, consume memory, and are evaluated on every subsequent object event for the affected class.

Tasks

• Add tests

Summary by CodeRabbit

• Bug Fixes

  • Fixed LiveQuery subscription cleanup when clients reuse request IDs with different queries, preventing orphaned subscriptions from persisting on the server.
  • Ensured subscriptions are properly replaced rather than duplicated when the same request ID is reused.

• Tests

  • Added comprehensive test suite validating subscription lifecycle behavior for duplicate request ID scenarios.

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 096063fc-50f2-49b6-9100-51fe7f0a6ec6

📥 Commits

Reviewing files that changed from the base of the PR and between c700ebd and 24ce5f9.

📒 Files selected for processing (4)

• spec/ParseLiveQuery.spec.js
• spec/helper.js
• src/LiveQuery/ParseLiveQueryServer.ts
• src/LiveQuery/Subscription.js

---

📝 Walkthrough

Walkthrough

This PR fixes LiveQuery subscription leaks when clients reuse requestIds. It deduplicates requestId registrations in Subscription, guards server-side cleanup in ParseLiveQueryServer during disconnect/subscribe/unsubscribe phases, fixes mock caching in the test harness, and adds comprehensive end-to-end tests validating subscription replacement and event delivery isolation.

Changes

LiveQuery duplicate requestId handling

Layer / File(s)	Summary
Subscription requestId deduplication src/LiveQuery/Subscription.js	addClientSubscription checks for existing requestId before registering, preventing duplicate (clientId, requestId) entries that complicate cleanup.
Server-side lifecycle cleanup guards src/LiveQuery/ParseLiveQueryServer.ts	Disconnect, subscribe (with prior-subscription teardown), and unsubscribe paths now conditionally guard access to per-class subscription maps, removing orphaned class/subscription entries only when no clients remain.
Test harness mock-caching fix spec/helper.js	jasmine.mockLibrary now caches the original export only once per library, preventing re-mocks from overwriting the stored original and breaking jasmine.restoreLibrary restoration across test runs.
LiveQuery duplicate requestId test suite spec/ParseLiveQuery.spec.js	New suite with raw WebSocket clients validates subscription replacement, multi-client isolation, event delivery divergence, and post-cleanup update operations when requestIds are reused across queries, classes, and disconnects.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• parse-community/parse-server#10414: Both PRs update ParseLiveQueryServer's disconnect-side cleanup of subscription/class maps, with the retrieved PR adding a disconnect test verifying cleanup behavior.
• parse-community/parse-server#10133: Both PRs modify _handleSubscribe in src/LiveQuery/ParseLiveQueryServer.ts—the main PR changes subscription replacement for duplicate requestIds, while the other adds CLP gating at subscribe time.

🚥 Pre-merge checks | ✅ 7

✅ Passed checks (7 passed)

Check name	Status	Explanation
Title check	✅ Passed	The pull request title clearly summarizes the main fix: preventing LiveQuery subscriptions from leaking when clients reuse requestIds.
Description check	✅ Passed	The PR description includes an Issue section describing the problem and a Tasks section showing tests were added, but lacks an Approach section explaining the implementation changes.
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.
Security Check	✅ Passed	No security vulnerabilities found. PR fixes LiveQuery subscription leaks while maintaining proper authorization boundaries and client isolation. All code paths are safely guarded.
Engage In Review Feedback	✅ Passed	PR has no substantive review feedback comments to engage with - only auto-generated CodeRabbit bot notifications about triggering a review. The check is not applicable to newly submitted PRs withou...

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 OpenGrep (1.22.0)

OpenGrep fatal error (exit code 2): [00.13][ERROR]: Error: exception Unix_error: No such file or directory stat spec/ParseLiveQuery.spec.js
Raised by primitive operation at UTmp.replace_named_pipe_by_regular_file_if_needed in file "libs/commons/UTmp.ml", line 145, characters 8-27
Called from Scan_CLI.replace_target_roots_by_regular_files_where_needed.(fun) in file "src/osemgrep/cli_scan/Scan_CLI.ml", lines 1086-1087, characters 19-65
Called from List_.fast_map in file "libs/commons/List_.ml", line 81, characters 17-20
Called from

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.60%. Comparing base (f12e1c3) to head (24ce5f9).
⚠️ Report is 1 commits behind head on alpha.

Additional details and impacted files

@@            Coverage Diff             @@
##            alpha   #10499      +/-   ##
==========================================
+ Coverage   92.59%   92.60%   +0.01%     
==========================================
  Files         193      193              
  Lines       16928    16941      +13     
  Branches      234      240       +6     
==========================================
+ Hits        15674    15689      +15     
+ Misses       1231     1229       -2     
  Partials       23       23              

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[mtrezza]

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[parseplatformorg]

🎉 This change has been released in version 9.9.1-alpha.8