Function default_socket_path 

pub fn default_socket_path() -> PathBuf

Default UDS socket path. Resolves at call time so a daemon started with XDG_RUNTIME_DIR=/foo and a client started later without the var both look in the same place (the XDG fallback).

Every arm is ABSOLUTE or it is skipped. Both env arms used to take their variable verbatim, and only the literal /tmp/tear.sock third arm was safe. That defeats the guarantee the paragraph above is making: with XDG_RUNTIME_DIR="" the result is the bare relative tear.sock, so “the same place” becomes the process’s cwd and a daemon started from $HOME and a client started from a repo bind and dial different sockets. Neither errors — they simply never meet.