Codex review pointed out that even with the sync-assets fix applied,
_build_web_ui still crashes on a stock Windows console before reaching
npm: Python stdout defaults to cp1252 (or similar) and raises
UnicodeEncodeError when print() hits the arrow/check glyphs used for
status messages (→, ✗, ⚠, ✓). Reproduced locally in PowerShell:
$ PYTHONIOENCODING=cp1252 python -c "from hermes_cli.main import _build_web_ui; _build_web_ui(Path('web'), fatal=True)"
UnicodeEncodeError: 'charmap' codec can't encode character '\u2192' ...
The previous PR body claimed "end-to-end verified on Windows 11", but
that was under the venv's default (utf-8) stdout. A plain `py` or
PowerShell invocation would still fail before sync-assets ever ran.
Fix: inner _say() helper that falls back to
text.encode(sys.stdout.encoding, errors="replace")
when print() raises UnicodeEncodeError. Glyphs degrade to '?' on
ASCII / cp1252 consoles; utf-8 consoles are unaffected. Verified the
full build pipeline runs to completion with PYTHONIOENCODING=cp1252.
Scoped tightly to _build_web_ui (the function this PR already touches);
other call sites in the codebase with the same risk are out of scope.
Three Windows-only bugs in the web-dashboard build path. Each is small,
scoped, and verified end-to-end on Windows 11 — including under a stock
cmd.exe / PowerShell console with its default cp1252 encoding.
1. `sync-assets` shells out to Unix-only commands
web/package.json hard-codes `rm -rf … && cp -r …`. Neither exists on
Windows cmd.exe. `hermes_cli/main.py::_build_web_ui` runs npm via
subprocess (which on Windows defaults to cmd.exe), so the prebuild
hook crashed before Vite ever ran and the dashboard never built.
Fix: web/scripts/sync-assets.mjs — ~20 lines of Node using fs.rmSync
+ fs.cpSync (stdlib, Node >= 16.7). No new deps, identical behavior
on POSIX and Windows.
2. Build failures were silent
_build_web_ui ran both subprocess calls with capture_output=True and
never relayed the captured buffers on failure. Users saw 'Web UI
build failed' and nothing else — no stdout, no stderr, no hint that
the real problem was 'rm is not recognized'.
Fix: inner _relay() helper that decodes and prints stdout + stderr
(utf-8, errors='replace') whenever a step returns non-zero. Replaces
the existing stderr_tail-only relay on the build path; success path
is unchanged. (stderr_tail is preserved for the stale-dist fallback
branch added by #23817.)
Salvaged from #13368 by @johnisag onto current main. Conflict
resolution preserves main's improvements:
- _run_npm_install_deterministic() (replaces bare subprocess.run for
npm install)
- npm-build retry-after-sleep for Windows boot-time races (#23817)
- stale-dist fallback for non-interactive callers (#23817)
Closes#25073, #13368.
ioannis