In _detect_env.py:29-30, if the first detector returns a path that doesn't exist, break aborts the entire loop — conda and poetry detectors never get a chance to run:

for detect in detection_funcs:
    path = detect()
    if not path:
        continue
    if not path.exists():
        break          # <-- should be continue
    return str(path)

For example, if VIRTUAL_ENV points to a stale/removed directory, the user gets SystemExit even if CONDA_PREFIX is set to a valid environment.

Fix: change break to continue.