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spawn_detached

lean_ctx::ipc::process

Function spawn_detached 

Source 
pub fn spawn_detached(cmd: &mut Command) -> Result<Child>
Expand description

Spawn a long-lived background process (proxy, daemon) detached from the current process so it survives the parent’s exit.

On Unix a child simply outlives its parent, so this is a plain spawn. On Windows the child inherits the parent’s console and — crucially — its Job object. AI clients (OpenCode, Codex, Claude Code) run MCP servers inside kill-on-close Jobs; without detachment the auto-started proxy dies the moment the client recycles its MCP process, which users observe as “Cannot connect to API: The socket connection was closed unexpectedly” plus repeated proxy cold-starts (GL #545).

Strategy on Windows:

  1. DETACHED_PROCESS | CREATE_NEW_PROCESS_GROUP | CREATE_BREAKAWAY_FROM_JOB — fully detached, escapes the parent’s Job.
  2. If the Job denies breakaway, CreateProcess fails with ERROR_ACCESS_DENIED; retry without the breakaway flag (still console-detached, which covers non-Job parents).