Tests did monkeypatch.setattr(<facade module>, name) where name is now defined in a
sibling module and the production path reads the sibling's binding. Where production
reads through BOTH bindings the setattr is duplicated onto the defining module (import
added next to the existing alias import); where only the sibling reads it the target is
repointed. Seams whose production readers go through the facade are left alone.
The gateway auto-restart phase used to swallow every exception at debug
level, so tests driving cmd_update end-to-end never noticed it touching
real gateway discovery. With #78574 surfacing an aborted restart as a
failed update, an unmocked find_gateway_pids on a box with a live
gateway hits the conftest live-system guard and turns into a spurious
sys.exit(1).
Add an autouse fixture in test_cmd_update.py (discovery returns nothing,
systemd unsupported) and the same seams in test_update_head_moved_gate's
helper so the phase is a clean no-op for tests that do not assert on
gateway restarts.
A detached/pinned checkout can report 'N new commit(s)' against origin,
run the ff-only merge successfully, and still sit on the old commit
afterward (the branch-switch step re-detaches to the raw SHA). Before
this guard 'hermes update' printed '✓ Code updated!' and reinstalled
deps + rebuilt the desktop app against the stale tree - no error, no
warning, 'hermes doctor' healthy.
Compare pre-pull and post-pull HEAD; if they match, fail loudly with a
reattach hint instead of claiming success.
Teknium