[Dietrich Travkin (travkin79)]

Related to #408, #373

Since #373 removed the CopilotLanguageClient.workspaceFolders() override, LSP4E announces every open project as a
workspace folder in initialize and workspace/didChangeWorkspaceFolders. With ~400 projects, the CLS is
CPU-bound for 8 – 13 minutes after startup; with ~60 projects, for a few seconds (see analysis in #408).

Changes

• Restore the override: announce only the Eclipse workspace root, as before Remove semantic workspace search integration #373.
• Chat, templates, customization files, modes and MCP requests still pass their project folders explicitly.

Risks

• Projects located outside the workspace directory are no longer known to the CLS as workspace folders.
• If the workspace directory contains a large tree, recursive searches in the CLS may become more expensive.

Verification

Verified on RHEL 9.6 with ~400 projects: the CLS is no longer CPU-bound for minutes after starting Eclipse. The
custom instructions listed in the preferences are the same as before. Not yet verified: whether custom
instructions are applied in chat responses, and the other Copilot features.

This is a workaround; the root cause is in the CLS (see #408). Feel free to reject it in favour of a CLS fix.

[Copilot]

🔵 Needs a closer look

Integration validation is needed to confirm startup improvement, initialization and folder-change behavior, and acceptable handling of external projects and large workspace directories.

No open issues 🎉

What changed in this PR

Restores workspace-root-only folder reporting to the Copilot language client to reduce startup delays in workspaces with many projects, addressing the regression described in #408 after #373.

Changes:

• Overrides workspaceFolders() to return only the Eclipse workspace root.
• Adds a test verifying that an open project does not appear as a separate workspace folder.

File	Description
com.microsoft.copilot.eclipse.core/​src/​com/​microsoft/​copilot/​eclipse/​core/​lsp/​CopilotLanguageClient.java	Restores workspace-root-only folder reporting.
com.microsoft.copilot.eclipse.core.test/​src/​com/​microsoft/​copilot/​eclipse/​core/​lsp/​CopilotLanguageClientTests.java	Tests folder reporting with an open project.

_{Review effort: Balanced}

[Andrey Loskutov (iloveeclipse)]

All my projects reside outside of the Eclipse workspace.
If I see it right, for our ~400 projects located in a single git repo, only the common root should be announced as "workspace folder" to CLS? And that would be the git working dir.

[Dietrich Travkin (travkin79)]

All my projects reside outside of the Eclipse workspace. If I see it right, for our ~400 projects located in a single git repo, only the common root should be announced as "workspace folder" to CLS? And that would be the git working dir.

Yes, that's one option..

With this PR we announce only the Eclipse workspace root, exactly as 0.20 did (#136 until #373). Chat, custom
instructions, prompts, modes and MCP requests pass the project folders explicitly per request, so the CLS still
gets the projects where these features need them. On RHEL the list of custom instructions was unchanged; I have
not yet verified everything else (e.g. instructions being applied in responses).

Announcing the common git root instead would also reduce the number of folders, but that root is a huge tree (in
our case 55 GB with ~82k directories), which the CLS would then watch. That might trade one performance problem
for another.

The proper fix is in the CLS: it calls rewatchAll() for every added folder one by one, with O(N²) path checks
(see the analysis in #408). Processing the added folders as one batch would make this PR unnecessary.

Andrey Loskutov (@iloveeclipse), it would be great if you could find some time to test this PR with some of your workspaces.