Description

Sidecar crashes or hangs immediately on startup when running in a repository with hierarchical branch names (e.g., feat/ui) or when multiple conversation adapters are enabled.

Symptoms

1. Immediate Crash (Segfault or Panic):
   • panic: runtime error: invalid memory address in workspace plugin
   • fatal error: concurrent map writes in OpenCode adapter
2. Infinite Hang:
   • Application freezes on startup "loading sessions..."
   • ps aux shows thousands of git processes (zombies or active)
3. Resource Exhaustion:
   • syscall.forkExec failures due to file descriptor exhaustion

Root Cause Analysis

After deep investigation, we identified 5 distinct bugs contributing to this instability:

1. Worktree Path Construction Failure

Location: internal/plugins/workspace/worktree.go
Cause: When creating a worktree for a branch with slashes (e.g., feat/ui), the code used the raw branch name as the directory name.
filepath.Join(parent, "feat/ui") -> /path/to/parent/feat/ui.
Since the feat/ directory doesn't exist in the parent, the git worktree add command fails or causes internal logic to panic.

2. Concurrent Map Write in OpenCode Adapter

Location: internal/adapter/opencode/adapter.go
Cause: The sessionIndex map was being written to by multiple goroutines concurrently during parallel session loading.
Finding: This map was actually dead code—it was populated but never read.

3. Process Exhaustion in Default Branch Detection

Location: internal/plugins/workspace/diff.go
Cause: detectDefaultBranch spawns 1-3 git processes every time it's called. It is called frequently (e.g., on every update tick).
Effect: Spawns thousands of git processes per minute, exhausting file descriptors (syscall.forkExec fails).

4. Infinite Hangs (Missing Timeouts)

Locations: internal/plugins/gitstatus/tree.go, internal/plugins/conversations/plugin_loading.go
Cause:

• git status commands can hang indefinitely on large repos.
• Adapter Sessions() calls (e.g. Cursor) can hang indefinitely.
• The loader waited on a WaitGroup without a timeout, causing a permanent freeze if any single adapter hung.

5. Cursor Adapter Malformed JSON Crash

Location: internal/adapter/cursor/adapter.go
Cause: json.Unmarshal panic/error when encountering malformed messages in Cursor chat history.

Fix

A comprehensive fix has been implemented in PR #136 which addresses all these issues:

• Sanitizes worktree directory creation (ensures parent dirs exist)
• Removes thread-unsafe dead code
• Caches default branch detection
• Adds timeouts to all external command execution
• Adds defensive error handling for JSON parsing