teknium1 hit ModuleNotFoundError: No module named 'hermes_bootstrap' after
a code update, on both his Windows machine AND his Linux workstation. The
failure mode is real and affects every user who updates hermes by any path
OTHER than a fully-successful ``hermes update``.
## What happens
hermes_bootstrap.py is a top-level module registered via pyproject.toml's
``py-modules`` list (added by Brooklyn's Windows UTF-8 stdio work). It
must be registered in the venv's editable-install .pth file before Python
can find it as a bare ``import hermes_bootstrap``.
``hermes update`` handles this correctly: (1) git reset --hard, (2) clear
__pycache__, (3) uv pip install -e . (re-registers the package including
the new py-modules list), (4) restart.
BUT if any step AFTER (1) fails — network blip during pip install, PEP 668
on a system Python, venv locked, uv not in PATH, a crash mid-update — the
user is left with new code that references hermes_bootstrap and a venv
that doesn't know about it. Every hermes invocation after that crashes
with ModuleNotFoundError, including ``hermes update`` itself. No recovery
path without manual `uv pip install -e .`.
Also affects users who ``git pull`` the repo directly without running
hermes update — relatively common for developers.
## Fix
Wrap ``import hermes_bootstrap`` in a try/except ModuleNotFoundError
across all 6 entry points (hermes_cli/main, run_agent, gateway/run,
acp_adapter/entry, cli, batch_runner). On Windows, missing bootstrap
means the UTF-8 stdio setup doesn't run — degraded behavior (Unicode
chars may fail to print) but NOT a crash. POSIX is unaffected either way
since the bootstrap is a no-op there.
Once hermes is running again, the user can ``hermes update`` to fully
recover.
## Test update
tests/test_hermes_bootstrap.py::test_entry_point_imports_bootstrap
scans for the first top-level import in each entry point and asserts it
is hermes_bootstrap. Extended the check to accept a Try block whose body
is a lone Import of hermes_bootstrap — that's the recovery-friendly form
we just introduced.
Verified behavior by ``mv hermes_bootstrap.py hermes_bootstrap.py.bak``
and confirming ``python -c "import hermes_cli.main"`` succeeds. 82/82
tests pass (hermes_bootstrap + windows-native + windows-compat).
Codebase-wide fix for Python-on-Windows UTF-8 footguns, complementing
the earlier execute_code sandbox fixes (which remain load-bearing for
when the sandbox explicitly scrubs child env).
Problem: Python on Windows has two long-standing text-encoding pitfalls:
1. sys.stdout/stderr are bound to the console code page (cp1252 on
US-locale installs) — print('café') crashes with UnicodeEncodeError.
2. Subprocess children don't know to use UTF-8 unless PYTHONUTF8 and/or
PYTHONIOENCODING are set in their env — so any Python we spawn
(linters, sandbox children, delegation workers) hits the same bug.
Solution: A tiny bootstrap module (hermes_bootstrap.py) imported as the
first statement of every Hermes entry point:
- hermes_cli/main.py (hermes / hermes-agent console_script)
- run_agent.py (hermes-agent direct)
- acp_adapter/entry.py (hermes-acp)
- gateway/run.py (messaging gateway)
- batch_runner.py (parallel batch mode)
- cli.py (legacy direct-launch CLI)
On Windows, the bootstrap:
- os.environ.setdefault('PYTHONUTF8', '1') (PEP 540 UTF-8 mode)
- os.environ.setdefault('PYTHONIOENCODING', 'utf-8')
- sys.stdout/stderr/stdin.reconfigure(encoding='utf-8', errors='replace')
Children inherit the env vars → they run in UTF-8 mode.
Current process's stdio is reconfigured → print('café') works now.
On POSIX (Linux/macOS), the bootstrap is a complete no-op. We don't
touch LANG, LC_*, or anything else — users who have intentionally
configured a non-UTF-8 locale aren't affected. POSIX systems are
already UTF-8 by default in 99% of modern setups, so there's nothing
to fix.
setdefault() (not overwrite) means users who explicitly set PYTHONUTF8=0
or PYTHONIOENCODING=cp1252 in their environment are respected.
What this does NOT fix: bare open(path, 'w') calls in the *parent*
process still default to locale encoding because PYTHONUTF8 is only
read at interpreter init. A ruff PLW1514 sweep (separate follow-up)
will add explicit encoding='utf-8' at those ~219 call sites for
belt-and-suspenders.
Tests (17): 16 passed, 1 skipped on Windows.
- Windows: env vars set, stdio reconfigured, child inherits UTF-8 mode
- POSIX: complete no-op (verified on fake POSIX + skipped on real
POSIX since we don't have a Linux box in this session)
- Idempotence: multiple calls safe
- Graceful degradation: non-reconfigurable streams don't crash
- User opt-out: explicit PYTHONUTF8=0 is respected
- Load order: every entry point's FIRST top-level import is
hermes_bootstrap, enforced by an AST-level parametrized test
pyproject.toml: added hermes_bootstrap to py-modules so it ships with
pip installs.
