Runaway copilot-file-search thread consumes CPU and unbounded disk while session is idle

Version: GitHub Copilot CLI 1.0.83-3 on Ubuntu 24.04

Summary

While a copilot --yolo session reports its status as idle, an internal copilot-file-search thread can continue running indefinitely, pinning a CPU core and writing an unbounded per-process diagnostic log under ~/.copilot/logs/ until the disk fills to 100%.

Observed behavior

• The session's foreground process stays alive and its reported status is idle, but the process is not actually idle at the OS level.
• The internal copilot-file-search thread crawls/indexes the working directory at ~50% CPU and does not stop on its own.
• The per-process diagnostic log in ~/.copilot/logs/ grows continuously — observed rates around 8 MiB per 10 seconds — with no apparent size cap or rotation. Individual logs reached 6–22 GB before intervention.
• On large or deeply nested directory trees, the crawler appears to get stuck (repeated traversal, symlink-loop-like behavior) rather than completing and going quiet.

Impact

• Root filesystem exhaustion (reached 100% used in the worst case), which affects the whole machine, not just the session.
• Sustained CPU consumption for an ostensibly idle session.

Reproduced

Seen multiple times in a 24h span, all with the identical signature: idle status + active copilot-file-search thread + a continuously growing diagnostic log under ~/.copilot/logs/. Killing the process is the only thing that stops it; the log then has to be deleted manually to reclaim space.

Expected behavior

• File-search/indexing should terminate (or throttle) when the session is idle.
• The crawler should detect and break traversal loops instead of looping indefinitely.
• Diagnostic logs should be size-capped or rotated so a single session cannot exhaust the disk.

まずアイドル状態のセッションの動作を再現し、~/.copilot/logs/ 配下のプロセスごとのファイルと併せて copilot-file-search のアクティビティを調査します。トラバーサルが繰り返されるか、ログが無制限に増加するかを追跡します。アイドル状態のセッションがインデックス作成を停止またはスロットルし、トラバーサルループが終了し、診断ログに上限が設定されるかローテーションされれば完了です。