VS Code Container Attach Crash - Debugging Report #

Date: December 27, 2025
Issue: VS Code crashes/halts when running start script to attach to devcontainer

Environment #

• VS Code: 1.107.1 (994fd12f8d3a5aa16f17d42c041e5809167e845a)
• devcontainer CLI: 0.80.3
• Container: aesthetic (running)
• Host OS: Fedora Linux

Symptoms #

1. CodeWindow: detected unresponsive errors in main.log
2. fileWatcher crashed with code 15 and reason 'killed'
3. renderer process gone (reason: crashed, code: 132)
4. Lock file conflicts: EEXIST: file already exists...vscode.lock

Root Causes Identified #

1. Stale Lock Files #

/home/me/.vscode-server/data/User/workspaceStorage/e316bf54877144e484c7d72e8e778826/vscode.lock
Content: {"pid":2356,"willReleaseAt":0}

When VS Code crashes, it doesn't clean up lock files. Subsequent connections fail trying to acquire the same lock.

2. Multiple VS Code Server Processes #

Found multiple processes running simultaneously:

• fileWatcher processes using 55%+ and 79%+ CPU
• Multiple extensionHost processes
• Multiple vscode-remote-containers-server processes

This indicates VS Code is spawning new connections without cleaning up old ones.

3. Previous Copilot Chat Extension Bug #

github.copilot-chat-0.35.2 had a navigator global bug that crashed the extension host. This was mitigated by:

• Adding remote.extensionKind: {"github.copilot-chat": ["ui"]} to devcontainer.json
• Adding settingsSync.ignoredExtensions: ["github.copilot-chat", "github.copilot"]

4. attached-container vs dev-container URI Confusion #

The start script has been oscillating between:

• vscode-remote://attached-container+{hex} - Attaches to existing container, ignores devcontainer.json
• vscode-remote://dev-container+{hex} - Uses devcontainer.json settings

The attached-container approach syncs extensions from host, including the buggy Copilot Chat.

Proposed Solution #

Immediate Fix Script #

Create a cleanup script to run before attaching:

function ac-cleanup-vscode-server
    echo "🧹 Cleaning up stale VS Code server state..."
    
    # Kill orphaned processes in container
    docker exec aesthetic sh -c "pkill -9 -f 'vscode-server' 2>/dev/null" || true
    
    # Remove stale lock files
    docker exec aesthetic sh -c "rm -f /home/me/.vscode-server/data/User/workspaceStorage/*/vscode.lock" 2>/dev/null || true
    
    # Clear extension host cache
    docker exec aesthetic sh -c "rm -rf /home/me/.vscode-server/data/logs/*" 2>/dev/null || true
    
    echo "✅ Cleanup complete"
end

Updated acd Function #

function acd
    set -l workspace ~/aesthetic-computer
    
    # Pull latest
    cd $workspace
    git pull
    
    # Cleanup before connecting
    ac-cleanup-vscode-server
    
    # Use dev-container approach (respects devcontainer.json)
    set -l container_id (pwd | tr -d '\n' | xxd -c 256 -p)
    
    # Start CDP port forwarder
    pkill -f "socat.*9224" 2>/dev/null
    socat TCP-LISTEN:9224,bind=0.0.0.0,fork,reuseaddr TCP:127.0.0.1:9222 &
    
    # Open VS Code with dev-container URI
    code --folder-uri "vscode-remote://dev-container+$container_id/workspaces/aesthetic-computer" \
         --remote-debugging-port=9222 \
         --remote-allow-origins="*"
    
    cd -
end

devcontainer.json Settings to Prevent Extension Sync Issues #

{
  "customizations": {
    "vscode": {
      "settings": {
        "settingsSync.ignoredExtensions": ["github.copilot-chat", "github.copilot"],
        "remote.extensionKind": {
          "github.copilot-chat": ["ui"],
          "github.copilot": ["ui"]
        },
        "extensions.autoUpdate": false,
        "git.autorefresh": false,  // Reduce fileWatcher load
        "files.watcherExclude": {
          "**/node_modules/**": true,
          "**/.git/objects/**": true
        }
      }
    }
  }
}

Testing Steps #

1. Kill all VS Code processes on host:

   pkill -9 code
   pkill -9 code-insiders
   

2. Clean container VS Code state:

   docker exec aesthetic sh -c "rm -rf /home/me/.vscode-server/data /home/me/.vscode-server/extensions/*"
   

3. Restart container:

   docker restart aesthetic
   

4. Open via "Reopen in Container":

   • Open folder in VS Code: code ~/aesthetic-computer
   • Cmd/Ctrl+Shift+P → "Dev Containers: Reopen in Container"

5. If that works, test the start script

Files to Update #

• dotfiles/dot_config/fish/config.fish - acd and start functions
• .devcontainer/devcontainer.json - Extension and watcher settings

Related Commits #

• fix: remove orphaned feral-file submodules causing git hang
• fix: prevent copilot-chat from installing on remote
• fix: use dev-container URI instead of attached-container