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Fix listener leak in chat code block editor pool disposal ordering#303548

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copilot/fix-potential-listener-leak-again
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Fix listener leak in chat code block editor pool disposal ordering#303548
Copilot wants to merge 2 commits intomainfrom
copilot/fix-potential-listener-leak-again

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Copilot AI commented Mar 20, 2026

Listener leak (6500+) on global LanguageFeatureRegistry emitters caused by undisposed CodeEditorWidget instances in chat EditorPool. Each pooled CodeBlockPart holds a CodeEditorWidget whose EditorModeContext registers ~16 listeners on global language feature registries.

Root cause: In updateViewModel(), _editorPool.clear() ran before _onDidUpdateViewModel.fire(). The event triggers clearRenderedParts() on templates, which releases pool items back into the pool array via ResourcePool.release(). Since clear() already ran, these items sat in the pool indefinitely — never disposed, listeners never removed.

Changes:

  • Reorder updateViewModel() — fire the event first so templates release pool items, then clear pools to dispose them
  • Guard IDisposableReference.dispose() against double-release — prevents pool corruption where the same CodeBlockPart appears twice in the pool array
// Before (leaks): clear empties pool, then event releases items into empty pool — never disposed
this._editorPool.clear();
this._onDidUpdateViewModel.fire();

// After (fixed): event releases items into pool, then clear disposes them
this._onDidUpdateViewModel.fire();
this._editorPool.clear();

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  • disallowed.com
    • Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --no-sandbox --crashpad-handler-pid=9588 --enable-crash-reporter=ca5bbdb2-cd8e-49c8-8d3e-cb2bbfd0b78c,no_channel --user-data-dir=/tmp/vscode-tests-1774025468427 --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,17767181790482287149,5394987817279806358,262144 --enable-features=PdfUseShowSaveFilePicker --disable-features=LocalNetworkAccessChecks,ScreenAIOCREnabled,SpareRendererForSitePerProcess,TraceSiteInstanceGetProcessCreation --variations-seed-version --trace-process-track-uuid=3190708989122997041 nfig/composer/vendor/bin/sh de/extensions/desh (dns block)
    • Triggering command: .build/electron/code-oss .build/electron/code-oss test/unit/electron/index.js --crash-reporter-directory=/home/REDACTED/work/vscode/vscode/.build/crashes ./src/vs/workbench/contrib/chat/test/browser/widget/chatContentParts/ -c xtensions/markdown-math/tsconfig.json --pretty false --sourceMap --inlineSources /tsconfig.json in/sh es (dns block)
  • example.com
    • Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --no-sandbox --crashpad-handler-pid=9588 --enable-crash-reporter=ca5bbdb2-cd8e-49c8-8d3e-cb2bbfd0b78c,no_channel --user-data-dir=/tmp/vscode-tests-1774025468427 --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,17767181790482287149,5394987817279806358,262144 --enable-features=PdfUseShowSaveFilePicker --disable-features=LocalNetworkAccessChecks,ScreenAIOCREnabled,SpareRendererForSitePerProcess,TraceSiteInstanceGetProcessCreation --variations-seed-version --trace-process-track-uuid=3190708989122997041 nfig/composer/vendor/bin/sh de/extensions/desh (dns block)
    • Triggering command: .build/electron/code-oss .build/electron/code-oss test/unit/electron/index.js --crash-reporter-directory=/home/REDACTED/work/vscode/vscode/.build/crashes ./src/vs/workbench/contrib/chat/test/browser/widget/chatContentParts/ -c xtensions/markdown-math/tsconfig.json --pretty false --sourceMap --inlineSources /tsconfig.json in/sh es (dns block)
  • mobile.events.data.microsoft.com
    • Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --no-sandbox --crashpad-handler-pid=9588 --enable-crash-reporter=ca5bbdb2-cd8e-49c8-8d3e-cb2bbfd0b78c,no_channel --user-data-dir=/tmp/vscode-tests-1774025468427 --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,17767181790482287149,5394987817279806358,262144 --enable-features=PdfUseShowSaveFilePicker --disable-features=LocalNetworkAccessChecks,ScreenAIOCREnabled,SpareRendererForSitePerProcess,TraceSiteInstanceGetProcessCreation --variations-seed-version --trace-process-track-uuid=3190708989122997041 nfig/composer/vendor/bin/sh de/extensions/desh (dns block)
    • Triggering command: .build/electron/code-oss .build/electron/code-oss test/unit/electron/index.js --crash-reporter-directory=/home/REDACTED/work/vscode/vscode/.build/crashes ./src/vs/workbench/contrib/chat/test/browser/widget/chatContentParts/ -c xtensions/markdown-math/tsconfig.json --pretty false --sourceMap --inlineSources /tsconfig.json in/sh es (dns block)
  • redirector.gvt1.com
    • Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --no-sandbox --crashpad-handler-pid=7887 --enable-crash-reporter=ca5bbdb2-cd8e-49c8-8d3e-cb2bbfd0b78c,no_channel --user-data-dir=/tmp/vscode-tests-1774025278152 --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,7940741220924357645,3441140531715102107,262144 --enable-features=PdfUseShowSaveFilePicker --disable-features=LocalNetworkAccessChecks,ScreenAIOCREnabled,SpareRendererForSitePerProcess,TraceSiteInstanceGetProcessCreation --variations-seed-version --trace-process-track-uuid=3190708989122997041 -tmpfiles nce|instantiateVbash src/vs/workbench./scripts/test.sh (dns block)
    • Triggering command: .build/electron/code-oss .build/electron/code-oss test/unit/electron/index.js --crash-reporter-directory=/home/REDACTED/work/vscode/vscode/.build/crashes ./src/vs/workbench/contrib/chat/test/browser/widget/chatContentParts/ d rWidget\|new CodACCEPT src/vs/workbench/contrib/chat/browser/widget/chatContentParts/toolInvocationParts/ /home/REDACTED/.config/composer/vendor/bin/bash (dns block)
    • Triggering command: /proc/self/exe /proc/self/exe --type=utility --utility-sub-type=network.mojom.NetworkService --lang=en-US --service-sandbox-type=none --no-sandbox --crashpad-handler-pid=9588 --enable-crash-reporter=ca5bbdb2-cd8e-49c8-8d3e-cb2bbfd0b78c,no_channel --user-data-dir=/tmp/vscode-tests-1774025468427 --shared-files=v8_context_snapshot_data:100 --field-trial-handle=3,i,17767181790482287149,5394987817279806358,262144 --enable-features=PdfUseShowSaveFilePicker --disable-features=LocalNetworkAccessChecks,ScreenAIOCREnabled,SpareRendererForSitePerProcess,TraceSiteInstanceGetProcessCreation --variations-seed-version --trace-process-track-uuid=3190708989122997041 nfig/composer/vendor/bin/sh de/extensions/desh (dns block)

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When updateViewModel() is called, templates need to release their pool
items back before the pools are cleared. Previously, clear() was called
first, disposing only the available pool items. Then the event triggered
template clearing, which released items back into the pool arrays — but
those items were never disposed because clear() had already run.

Fix by reordering: fire the event first so templates release their pool
items, then clear the pools to properly dispose all released items.

Also guard IDisposableReference.dispose() against double-release which
could cause pool corruption.

Co-authored-by: jrieken <1794099+jrieken@users.noreply.github.com>
Agent-Logs-Url: https://github.com/microsoft/vscode/sessions/d4642fd3-0686-47a6-a0b0-776d87791453
Copilot AI changed the title [WIP] Fix potential listener leak issue #1ab Fix listener leak in chat code block editor pool disposal ordering Mar 20, 2026
Copilot AI requested a review from jrieken March 20, 2026 16:56
@jrieken jrieken requested a review from connor4312 March 23, 2026 08:37
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jrieken commented Mar 23, 2026

@connor4312 I believe you originally wrote this code

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jrieken commented Mar 23, 2026

ah, apparently fixed by #303620

@jrieken jrieken closed this Mar 23, 2026
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[1ab] potential listener LEAK detected, having 6511 listeners already. MOST frequent listener (6337)

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