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Cannot read properties of undefined (reading 'close') #49961

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#49990
Closed
Cannot read properties of undefined (reading 'close')#49961
#49990
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jakebailey
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BugA bug in TypeScriptFix AvailableA PR has been opened for this issue
Milestone
TypeScript 4.8.1

Description

@mjbvz
Matt Bierner (mjbvz)
opened on Jul 19, 2022

Bug Report

🔎 Search Terms

  • watcher
  • crash

🕗 Version & Regression Information

4.8.0-dev.20220711

Seems like a regression as I do not remember seeing this in TS 4.7

Details

When closing editors in VS Code, recently I've been seeing the following crash:

  ERR <semantic> TypeScript Server Error (4.8.0-dev.20220711)
Cannot read properties of undefined (reading 'close')
TypeError: Cannot read properties of undefined (reading 'close')
    at Object.close (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:6834:29)
    at Object.close (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:116840:29)
    at closeFileWatcherOf (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:116891:32)
    at Map.forEach (<anonymous>)
    at Object.clearMap (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:19668:13)
    at Object.clear (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:122531:16)
    at ConfiguredProject.Project.close (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:171446:38)
    at ConfiguredProject.close (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:172930:40)
    at ProjectService.removeProject (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:173991:25)
    at /Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:175861:86
    at Map.forEach (<anonymous>)
    at ProjectService.removeOrphanConfiguredProjects (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:175861:44)
    at ProjectService.cleanupAfterOpeningFile (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:175805:22)
    at ProjectService.applyChangesInOpenFiles (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:176009:26)
    at Session.handlers.ts.Map.ts.getEntries._a.<computed> (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:177372:46)
    at /Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:179564:96
    at IpcIOSession.Session.executeWithRequestId (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:179555:28)
    at IpcIOSession.Session.executeCommand (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:179564:41)
    at IpcIOSession.Session.onMessage (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:179592:35)
    at process.<anonymous> (/Users/matb/projects/vscode/node_modules/typescript/lib/tsserver.js:183758:31)
    at process.emit (node:events:390:28)
    at emit (node:internal/child_process:917:12)
    at processTicksAndRejections (node:internal/process/task_queues:84:21): Error: <semantic> TypeScript Server Error (4.8.0-dev.20220711)

I can't repo this reliably but here's the complete log of a session the crashed (it's quite large)
tsserver.log.zip

Activity

  1. DanielRosenwasser commented on Jul 20, 2022

    @DanielRosenwasser
    Daniel Rosenwasser (DanielRosenwasser)
    on Jul 20, 2022
    Member

    First error in logs is possibly #49310

  2. Ryan Cavanaugh (RyanCavanaugh)
    assigned
    Jake Bailey (jakebailey)
    on Jul 20, 2022
  3. Ryan Cavanaugh (RyanCavanaugh)
    added
    BugA bug in TypeScript
    on Jul 20, 2022
  4. Ryan Cavanaugh (RyanCavanaugh)
    added this to the TypeScript 4.8.1 milestone on Jul 20, 2022

  5. jakebailey commented on Jul 21, 2022

    @jakebailey
    Jake Bailey (jakebailey)
    on Jul 21, 2022
    Member

    Based on the trace (closeFileWatcherOf followed by two close calls), I think this is caused by a double-close of this watcher:

    TypeScript/src/compiler/sys.ts

    Line 1098 in 7b76416

    watcher = undefined!;

    It's not clear to me from the API of FileWatcher whether or not a double close is intended to be to be legal (I'll add some asserts to various implementations to check), but I think making this one not crash is straightforward.

  6. TypeScript Bot (typescript-bot)
    added
    Fix AvailableA PR has been opened for this issue
    on Jul 21, 2022

  7. jakebailey commented on Jul 21, 2022

    @jakebailey
    Jake Bailey (jakebailey)
    on Jul 21, 2022
    Member

    I can't say I know for sure if the API should allow double closes or not; there are clearly some refcounted file watchers which just start returning early once their references are up. There are also some other cases (different from this issue's trace) which could potentially crash if some invariant were violated, but we a aren't seeing those. So I'm inclined to go the safer route that doesn't do a undefined!.

  8. Jake Bailey (jakebailey)
    closed this as completedin #49990on Jul 22, 2022
  9. microsoft
    locked as resolved and limited conversation to collaborators on Oct 22, 2025
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