Fallback to folder if worktree creation fails in bg sessions

[DonJayamanne]

Fixes microsoft/vscode#291641

[Copilot]

Pull request overview

This pull request aims to fix the fallback behavior when worktree creation fails, ensuring that the system properly falls back to using the workspace folder without worktree isolation.

Changes:

• Modified the initialization of workingDirectory to use sessionWorkspaceFolder as a fallback
• Updated isWorkspaceFolderWithoutRepo flag to true when no repository is selected
• Updated isWorkspaceFolderWithoutRepo flag to true when worktree creation fails

Comments suppressed due to low confidence (2)

src/extension/chatSessions/vscode-node/copilotCLIChatSessionsContribution.ts:1115

• The ternary condition on selectedRepository is unnecessary because selectedRepository is always undefined at this point (it's declared as undefined on line 1114). This line will always evaluate to sessionWorkspaceFolder. Consider simplifying to: const workingDirectory = sessionWorkspaceFolder;

			const workingDirectory = selectedRepository ? this.workspaceService.getWorkspaceFolder(selectedRepository) : sessionWorkspaceFolder;

src/extension/chatSessions/vscode-node/copilotCLIChatSessionsContribution.ts:1148

• When worktree creation fails at line 1148, workingDirectory may be undefined even though selectedRepository is defined. The workingDirectory variable is set at line 1115 before selectedRepository is potentially assigned (at lines 1120 or 1131). When falling back from a failed worktree creation, consider using this.workspaceService.getWorkspaceFolder(selectedRepository) to get the proper workspace folder for the repository, rather than relying on the stale workingDirectory value that was calculated before selectedRepository was known.

				return { workingDirectory, worktreeProperties: undefined, isWorkspaceFolderWithoutRepo: true, cancelled: false };