[Dietrich Travkin (travkin79)]

Related to #408

While the CLS is busy, closing Eclipse hangs invisibly (window closed, JVM still running):
UserPreferenceService.dispose() waits without limit for conversation/persistence. On RHEL this request was
answered after 11 min 41 s; only then were shutdown/exit sent. A busy CLS also does not react to
shutdown/exit, so it can outlive Eclipse, keep using 100 % CPU and accumulate across restarts. During
shutdown, late requests could even start a new CLS.

Changes

• Saving the chat preferences on shutdown waits at most 2 s for the CLS, also while a preference load is still
  waiting for the CLS. On timeout, only the chat input history of the session may not be saved; other preferences
  are saved when they change.
• On stop, wait up to 6 s (LSP4E waits 5 s for the shutdown response), then force-kill the CLS and its
  descendant processes (e.g. MCP servers), including those started during the wait.
• Do not start the CLS while the Copilot core bundle is stopping.

Overlaps with #455 (bounded shutdown flush), but can be merged on its own.

Verification

Verified on RHEL 9.6 with ~400 projects: closing Eclipse while the CLS was busy previously took ~12 minutes
(until the CLS went idle). With this PR, Eclipse exits after ~8 s and the CLS process is gone:

!ENTRY com.microsoft.copilot.eclipse 1 0 2026-10-23 18:50:13.567
!MESSAGE [Info] Language server did not provide the persistent path in time, skipping

!ENTRY org.eclipse.lsp4e 2 0 2026-10-23 18:50:18.600
!MESSAGE The server did not stop after 5 seconds

!ENTRY com.microsoft.copilot.eclipse 1 0 2026-10-23 18:50:19.600
!MESSAGE [Info] Copilot language server did not exit in time, killing it

[Copilot]

🟡 Changes recommended

Preference-monitor contention can still block shutdown indefinitely, and processes spawned during the grace period can escape cleanup.

2 open issues

• Shutdown misses descendants created during the grace period · New
• Shutdown can block indefinitely on synchronized preference loading · New

What changed in this PR

This PR addresses the shutdown symptoms associated with #408 by limiting preference-path waits and adding process-tree cleanup for an unresponsive Copilot language server.

Changes:

• Adds a two-second shutdown timeout for preference-path requests.
• Waits up to six seconds for server exit, then forcibly terminates the server and captured descendants.
• Blocks server startup while the core bundle is stopping and adds regression tests.

File	Description
com.microsoft.copilot.eclipse.ui/​src/​com/​microsoft/​copilot/​eclipse/​ui/​chat/​services/​UserPreferenceService.java	Applies the preference timeout during disposal.
com.microsoft.copilot.eclipse.ui/​src/​com/​microsoft/​copilot/​eclipse/​ui/​chat/​services/​ChatBaseService.java	Adds timeout-aware preference-path retrieval.
com.microsoft.copilot.eclipse.ui.test/​src/​com/​microsoft/​copilot/​eclipse/​ui/​chat/​services/​UserPreferenceServiceTest.java	Tests disposal with an unanswered persistence request.
com.microsoft.copilot.eclipse.core/​src/​com/​microsoft/​copilot/​eclipse/​core/​lsp/​LsStreamConnectionProvider.java	Prevents server startup during core shutdown.
com.microsoft.copilot.eclipse.core/​src/​com/​microsoft/​copilot/​eclipse/​core/​lsp/​CopilotLanguageServerConnection.java	Adds bounded exit waiting and forced process cleanup.
com.microsoft.copilot.eclipse.core.test/​src/​com/​microsoft/​copilot/​eclipse/​core/​lsp/​LsStreamConnectionProviderTests.java	Tests the shutdown startup guard.
com.microsoft.copilot.eclipse.core.test/​src/​com/​microsoft/​copilot/​eclipse/​core/​lsp/​CopilotLanguageServerProcessTests.java	Tests termination of an unresponsive server and its child.

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

Shutdown can still block indefinitely on monitor acquisition despite a successful path timeout; the deadline must cover locking or safely skip saving while loading, with a regression test using independently completed persistence futures.

1 open issue

• Bound shutdown while waiting for preference lock · New

2 resolved since last review

• Shutdown can block indefinitely on synchronized preference loading
• Shutdown misses descendants created during the grace period

_{Review effort: Balanced}

[Dietrich Travkin (travkin79)]

Hi Sheng Chen (@jdneo),
Do you have some time to also review and merge this PR? Do you see any issues left?

[Dietrich Travkin (travkin79)]

Hi Sheng Chen (@jdneo),
After fixing some review findings in a PR, the PR checks are not run automatically (CI run, AI code review, etc.). Could these automated checks be activated for copilot-for-eclipse, i.e. be executed after each PR push? I think, that would reduce effort on your side (you'd review PRs after all automatically identified findings were fixed) and would provide earlier feedback to contributors.