fix: wire ext host restart through utility process api

[deepak1556]

Fixes #296681

Followup to #293144 covering extension host restart path

[Copilot]

Pull request overview

This PR fixes the extension host restart path so that a blocked/unresponsive extension host is properly terminated via the utility process API, addressing the “rogue Code Helper (Plugin)” process reported in #296681.

Changes:

• Add a main-process waitForExit capability to the extension host starter and plumb a shared grace-time constant.
• Implement a local extension host disconnect() that requests graceful termination and then waits (with grace time) for the process to exit.
• Extend smoke coverage to validate that restarting the extension host replaces the PID and terminates the old process.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/smoke/src/areas/extensions/extension-host-restart.test.ts	Adds a smoke test that restarts the extension host and verifies old PID termination + new PID observed.
test/smoke/extensions/vscode-smoketest-ext-host/extension.js	Writes an “activation PID” marker on activation to support restart validation in smoke tests.
src/vs/workbench/services/extensions/electron-browser/localProcessExtensionHost.ts	Adds disconnect() for local ext host that sends terminate and waits for utility-process exit; tweaks dispose behavior.
src/vs/platform/extensions/electron-main/extensionHostStarter.ts	Implements waitForExit() and uses shared grace-time constant for window lifecycle binding.
src/vs/platform/extensions/common/extensionHostStarter.ts	Introduces extensionHostGraceTimeMs and adds waitForExit to the starter interface.

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[Copilot]

Pull request overview

This PR fixes the “Restart Extension Host” shutdown path so a blocked/rogue extension host utility process is reliably terminated (follow-up to window-lifecycle binding work) and adds a smoke test to prevent regressions (issue #296681).

Changes:

• Add a waitForExit capability to the IExtensionHostStarter utility-process API and expose it to the renderer-side extension host wrapper.
• Ensure local extension host disconnect() requests graceful termination and then waits (with a grace period) before force-killing.
• Add smoke test coverage validating that restarting the extension host kills a blocked old PID and spawns a new PID.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
test/smoke/src/areas/extensions/extension-host-restart.test.ts	Adds a smoke test for “Restart Extension Host” ensuring the old blocked PID is terminated and a new PID appears.
test/smoke/extensions/vscode-smoketest-ext-host/extension.js	Writes the ext host PID on activation so the smoke test can observe the new PID after restart.
src/vs/workbench/services/extensions/electron-browser/localProcessExtensionHost.ts	Implements disconnect() to send terminate + wait/force-kill via the utility process starter API.
src/vs/platform/extensions/electron-main/extensionHostStarter.ts	Wires windowLifecycleGraceTime to a shared constant and adds waitForExit implementation over WindowUtilityProcess.
src/vs/platform/extensions/common/extensionHostStarter.ts	Introduces extensionHostGraceTimeMs constant and adds waitForExit to the starter interface.

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