nfinite recursion (Shim <-> Native ping-pong) when executing copilotCLI via copilotCLIShim.js

[DongHyun-Yang]

Describe the bug

GitHub Issue Draft

Title: Infinite recursion (Shim <-> Native ping-pong) when executing copilotCLI via copilotCLIShim.js

Description

While developing tools utilizing copilotCli, I discovered a critical bug where the process spawns child processes indefinitely, leading to an Out of Memory (OOM) state or system hang.

Based on the analysis of the agent conversation history and process monitoring, the issue is not within the VS Code extension itself, but rather a recursive execution loop within the copilot CLI binary/shim layer.

Analysis & Evidence

The copilot executable is a shell script that calls copilotCLIShim.js using Electron as Node:

#!/bin/sh
unset NODE_OPTIONS
ELECTRON_RUN_AS_NODE=1 "/usr/share/code/code" "/home/dhyang/.config/Code/User/globalStorage/github.copilot-chat/copilotCli/copilotCLIShim.js" "$@"

When a single copilot command is executed, the process count explodes exponentially. In a controlled test, a single call resulted in over 2,100 processes within 60 seconds (approximately 37 forks per second).

Investigation Log

Below is the terminal output capturing the abnormal process growth during a single execution:

# Monitoring process count in background
while true; do n=$(pgrep -c -f "copilotCli" 2>/dev/null || echo 0); echo "$(date +%H:%M:%S) procs=$n"; sleep 1; done

# Executing a single command
START: 14:30:01
timeout 60 copilot --yolo --prompt "say hello" --model claude-sonnet-4.6 --silent --disable-builtin-mcps
...
END: 14:31:01 exit:124 (Timeout)

Key Findings:

• Process Explosion: 0 → 2,198 processes in 60 seconds.
• Symptom: The copilot CLI binary continuously forks child processes without termination.
• Root Cause Hypothesis: A "ping-pong" recursion between the copilot shim script and the native execution logic, where each process attempts to invoke another instance of itself.

Environment

• OS: Linux (Ubuntu/Debian based on /usr/share/code path)
• Extension: github.copilot-chat
• Component: copilotCli / copilotCLIShim.js

Affected version

GitHub Copilot CLI 1.0.11.

Steps to reproduce the behavior

No response

Expected behavior

No response

Additional context

No response