Unhandled exception may be causing Agent Mode to be stuck in "Working"

[lseppala]

Environment

This is using VSCode insiders

Version: 1.101.0-insider (Universal)
Commit: 3ba3a1b81843836b5ae4b37c6a0f71c39e7939c6
Date: 2025-06-10T22:38:08.015Z
Electron: 35.5.1
ElectronBuildId: 11727614
Chromium: 134.0.6998.205
Node.js: 22.15.1
V8: 13.4.114.21-electron.0
OS: Darwin x64 24.5.0

Situation

I continued an Agent-mode session from the previous day. After entering a new prompt, the Agent turn would complete a few requests but then eventually gets stuck I attempted restarting VSCode Insiders and updating VSCode Insiders to the latest version to no resolution.

Observations

I turned on Trace-level logs and monitored the logs available in the Telemetry output. What stood out was the following unhandled exception error:

2025-06-11 08:47:09.709 [trace] [Telemetry] telemetry/UnhandledError {"properties":{"msg":"Cannot read properties of null (reading 'isDisposed')","callstack":"TypeError: Cannot read properties of null (reading 'isDisposed')\n    at Jde.update (vscode-file://vscode-app/out/vs/workbench/workbench.desktop.main.js:650:24090)","abexp.assignmentcontext":"vsliv368cf:30146710;vspor879:30202332;vspor708:30202333;vspor363:30204092;vswsl492cf:30256198;pythonvspyt551:31249597;vscod805:30301674;c4g48928:30535728;962ge761:30841072;dsvsc014:30777825;dsvsc015:30821418;h48ei257:31000450;pythontbext0:30879054;cppperfnew:30980852;dwnewjupytercf:31046870;pythonrstrctxt:31093868;nativeloc1:31118317;e80f6927:31120813;dwcopilot:31158714;c3hdf307:31184662;6074i472:31201624;dwoutputs:31242946;customenabled:31248079;9064b325:31222308;copilot_t_ci:31222730;g012b348:31231168;pythoneinst12:31251391;bgtreat:31252123;c7cif404:31309980;pythonpulldiag:31287486;6gi0g917:31259950;61ibe868:31282443;996jf627:31264550;pythonrdcb7:31268811;usemplatestapi:31297334;jdghv92:31317040;747dc170:31275146;pythoncompactctx:31296835;6518g693:31302842;pylancecolor:31288664;generatesymbolt:31280541;convertfstringf:31280702;gendocf:31280703;nes6j6d6965:31321961;923gi514:31310909;b99bg931:31306656;fd45d811:31320948;convertlamdat:31319677;gce3e431:31315077;","common.machineId":"fec965ea781b8eab7b981ac206fa825b18687d3945d7d3e5d4dfd5df0a328e29","common.sqmId":"","common.devDeviceId":"4af069f5-02f1-4440-8ae6-f3f69752ee31","sessionID":"9f8a6723-357d-4fe5-b559-5ffd5263ebbc1749652915538","commitHash":"3ba3a1b81843836b5ae4b37c6a0f71c39e7939c6","version":"1.101.0-insider","common.platformVersion":"24.5.0","common.platform":"Mac","common.nodePlatform":"darwin","common.nodeArch":"x64","common.product":"desktop","timestamp":"2025-06-11T14:47:09.708Z","common.version.shell":"35.5.1","common.version.renderer":"134.0.6998.205","common.firstSessionDate":"Tue, 02 May 2023 17:49:58 GMT","common.lastSessionDate":"Wed, 11 Jun 2025 14:03:24 GMT","common.isNewSession":"0","common.remoteAuthority":"none"},"measurements":{"count":117,"common.timesincesessionstart":314170,"common.sequence":276,"common.cli":0}}

I repeated this process and each time it got stuck in "Working...", this exception occurred.

I am on the GitHub Copilot API team and checked the server-side logs to see if it was a problem on our end. I do not see any requests initiated when it gets stuck.

cc @isidorn

[isidorn]

I also heard other folk complaining about this in insiders. @roblourens would be good if you take a look - there is an clear exception in logs.

[roblourens]

Were there any other errors in the Window output channel? I wouldn't think that error would lead to this, I would guess it's the end result of another breakdown.

[isidorn]

@lseppala / @joaomoreno if you can consistently repro this additional details would really help.

[aiday-mar]

I was testing Copilot today and ran into this. In agentic mode, Copilot wanted to execute some tests. I clicked on continue and it got stuck in the state Running tests.... After 15 minutes or so, I paused the LLM execution and ran the request again.

Screen.Recording.2025-06-16.at.13.55.53.mov

[lseppala]

I have not been able to reproduce this since I've reported this error. I believe I updated and restarted VSCode Insiders to get it working again. Though it seems there has been at least one other report of this problem (#251475)

[roblourens]

@aiday-mar likely another issue, since it seems like it didn't start running the test tool. You could open a new issue and check for errors, if you see it again