fix: Windows statusline hook — UTF-8 stdin, system language, real console width

setup_hook.py

@@ -132,9 +132,19 @@ def _statusline_command_target_exists() -> bool:
 def _find_system_python() -> str:
     if sys.platform == "win32":
         executable = sys.executable
-        if executable and not getattr(sys, "frozen", False):
+        if (
+            executable
+            and not getattr(sys, "frozen", False)
+            and _is_ascii_path(executable)
+        ):
             return executable
-        return shutil.which("python") or "python"
+        # Claude Code can fail to spawn a command containing non-ASCII paths
+        # on Windows.  The hook is stdlib-only, so an ASCII-path Python from
+        # PATH (or the Windows launcher) is preferable to this app's venv.
+        for candidate in (shutil.which("python"), shutil.which("py")):
+            if candidate and _is_ascii_path(candidate):
+                return candidate
+        return "python"
     if os.path.exists("/usr/bin/python3"):
         return "/usr/bin/python3"
     executable = sys.executable
@@ -143,6 +153,10 @@ def _find_system_python() -> str:
     return shutil.which("python3") or "python3"
 
 
+def _is_ascii_path(value: str) -> bool:
+    return value.isascii()
+
+
 def _shell_arg(value: str) -> str:
     if sys.platform == "win32":
         # Claude Code runs statusLine commands through Git Bash when it is
@@ -165,15 +179,15 @@ def _uses_bundled_app_python(command: str) -> bool:
 def _migrate_windows_statusline_command_if_needed(
     settings: dict[str, Any] | None = None,
 ) -> None:
-    """Replace legacy backslash paths in usage-owned Windows statusLine commands."""
+    """Repair Windows usage commands with backslash or non-ASCII paths."""
     if sys.platform != "win32":
         return
     data = _load_settings() if settings is None else settings
     sl = data.get("statusLine")
     if not isinstance(sl, dict):
         return
     command = sl.get("command")
-    if not isinstance(command, str) or "\\" not in command:
+    if not isinstance(command, str) or ("\\" not in command and command.isascii()):
         return
     if "usage-statusline-forwarder" in command:
         new_command = _forwarder_command()
@@ -185,7 +199,9 @@ def _migrate_windows_statusline_command_if_needed(
         return
     sl["command"] = new_command
     _save_settings(data)
-    _append_hook_repair_log("migrate_windows_statusline", "backslash paths -> forward slashes")
+    _append_hook_repair_log(
+        "migrate_windows_statusline", "backslash/non-ASCII paths -> ASCII forward-slash command"
+    )
 
 
 def _append_hook_repair_log(action: str, detail: str) -> None:

tests/test_session_resume.py

@@ -6,6 +6,7 @@
 
 from __future__ import annotations
 
+import io
 import json
 import os
 import sys
@@ -18,6 +19,31 @@
 import usage_session_resume as mod
 
 
+def test_detect_lang_uses_windows_system_lang_when_env_is_empty(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    for key in ("USAGE_LANG", "TT_LANG", "LANG"):
+        monkeypatch.delenv(key, raising=False)
+    monkeypatch.setattr(mod, "_windows_system_lang", lambda: "zh_TW")
+
+    assert mod._detect_lang() == "zh-TW"
+
+
+def test_detect_lang_prefers_usage_lang_over_windows_system_lang(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv("USAGE_LANG", "ja")
+    monkeypatch.setattr(mod, "_windows_system_lang", lambda: "zh_TW")
+
+    assert mod._detect_lang() == "ja"
+
+
+def test_windows_system_lang_is_empty_off_windows(monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setattr(mod, "os", SimpleNamespace(name="posix"))
+
+    assert mod._windows_system_lang() == ""
+
+
 def test_windows_output_reconfigures_both_streams(monkeypatch: pytest.MonkeyPatch) -> None:
     class Stream:
         def __init__(self) -> None:
@@ -549,6 +575,27 @@ def test_main_emits_greeting_when_no_progress(
     assert out["hookSpecificOutput"]["additionalContext"] == "GREETING::"
 
 
+def test_main_reads_utf8_bytes_when_stdin_uses_cp950(
+    monkeypatch: pytest.MonkeyPatch, tmp_path: Path, capsys: pytest.CaptureFixture[str]
+) -> None:
+    monkeypatch.setenv("LANG", "en_US.UTF-8")
+    _sidecar(tmp_path, monkeypatch)
+    project = _project_dir(tmp_path)
+    current = project / "current.jsonl"
+    current.write_text("", encoding="utf-8")
+    payload = json.dumps(
+        {"transcript_path": str(current), "cwd": r"C:\\Users\\USER\\Desktop\\GitHub專案\\usage"},
+        ensure_ascii=False,
+    )
+    monkeypatch.setattr(
+        sys, "stdin", io.TextIOWrapper(io.BytesIO(payload.encode("utf-8")), encoding="cp950")
+    )
+
+    assert mod.main() == 0
+    out = json.loads(capsys.readouterr().out)
+    assert out["hookSpecificOutput"]["hookEventName"] == "SessionStart"
+
+
 def test_extract_commit_title_handles_heredoc_forms() -> None:
     # `git commit -F - <<'EOF'` has no `cat` prefix — the most common form, previously missed.
     assert (

tests/test_setup_hook.py

@@ -7,6 +7,7 @@
 from __future__ import annotations
 
 import json
+import shutil
 import sys
 import tomllib
 from collections.abc import Callable
@@ -220,6 +221,20 @@ def test_find_system_python_uses_current_interpreter_on_windows(
     assert setup_hook._find_system_python() == r"C:\\Program Files\\Python\\python.exe"
 
 
+def test_find_system_python_avoids_non_ascii_windows_interpreter(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setattr(sys, "executable", r"C:\\專案\\usage\\.venv\\Scripts\\python.exe")
+    monkeypatch.setattr(
+        shutil,
+        "which",
+        lambda name: r"C:\\Program Files\\Python\\python.exe" if name == "python" else None,
+    )
+
+    assert setup_hook._find_system_python() == r"C:\\Program Files\\Python\\python.exe"
+
+
 def test_windows_hook_commands_use_double_quotes(monkeypatch: pytest.MonkeyPatch) -> None:
     monkeypatch.setattr(sys, "platform", "win32")
     monkeypatch.setattr(
@@ -270,6 +285,37 @@ def test_windows_statusline_migration_rewrites_legacy_backslash_paths(
     assert data["usage"]["selfHealLog"][-1]["action"] == "migrate_windows_statusline"
 
 
+def test_windows_statusline_migration_rewrites_non_ascii_interpreter(
+    monkeypatch: pytest.MonkeyPatch,
+    setup_paths: SetupHookPaths,
+) -> None:
+    monkeypatch.setattr(sys, "platform", "win32")
+    monkeypatch.setattr(
+        setup_hook, "_find_system_python", lambda: r"C:\\Program Files\\Python\\python.exe"
+    )
+    setup_paths.settings.write_text(
+        json.dumps(
+            {
+                "statusLine": {
+                    "type": "command",
+                    "command": (
+                        r"C:/Users/USER/Desktop/GitHub專案/usage/.venv/Scripts/python.exe "
+                        f"{setup_paths.hook_target}"
+                    ),
+                }
+            }
+        ),
+        encoding="utf-8",
+    )
+
+    setup_hook._migrate_windows_statusline_command_if_needed()
+
+    data = json.loads(setup_paths.settings.read_text(encoding="utf-8"))
+    command = data["statusLine"]["command"]
+    assert command == expected_statusline_command(setup_paths.hook_target)
+    assert command.isascii()
+
+
 def test_setup_codex_replaces_only_tui_status_line(
     monkeypatch: pytest.MonkeyPatch, tmp_path: Path
 ) -> None:

tests/test_usage_statusline.py

@@ -22,6 +22,89 @@
 import usage_statusline
 
 
+def test_get_width_uses_conout_width_after_windows_pipe_failure(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    def raise_oserror(fd: int) -> os.terminal_size:
+        _ = fd
+        raise OSError("not a terminal")
+
+    monkeypatch.setattr(
+        usage_statusline,
+        "os",
+        SimpleNamespace(name="nt", get_terminal_size=raise_oserror),
+    )
+    monkeypatch.setattr(usage_statusline, "_conout_columns", lambda: 220)
+
+    assert usage_statusline.get_width() == 216
+
+
+@pytest.mark.parametrize("columns", (None, 0))
+def test_get_width_keeps_default_when_conout_is_unavailable(
+    monkeypatch: pytest.MonkeyPatch,
+    columns: int | None,
+) -> None:
+    def raise_oserror(fd: int) -> os.terminal_size:
+        _ = fd
+        raise OSError("not a terminal")
+
+    monkeypatch.setattr(
+        usage_statusline,
+        "os",
+        SimpleNamespace(name="nt", get_terminal_size=raise_oserror),
+    )
+    monkeypatch.setattr(usage_statusline, "_conout_columns", lambda: columns)
+
+    assert usage_statusline.get_width() == 116
+
+
+def test_get_width_does_not_probe_conout_off_windows(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    def raise_oserror(fd: int) -> os.terminal_size:
+        _ = fd
+        raise OSError("not a terminal")
+
+    def fail_probe() -> int:
+        raise AssertionError("CONOUT$ probe should not run off Windows")
+
+    monkeypatch.setattr(
+        usage_statusline,
+        "os",
+        SimpleNamespace(name="posix", get_terminal_size=raise_oserror),
+    )
+    monkeypatch.setattr(usage_statusline, "_conout_columns", fail_probe)
+
+    assert usage_statusline.get_width() == 116
+
+
+def test_statusline_detect_lang_uses_windows_system_lang_when_env_is_empty(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    for key in ("USAGE_LANG", "TT_LANG", "LANG"):
+        monkeypatch.delenv(key, raising=False)
+    monkeypatch.setattr(usage_statusline, "_windows_system_lang", lambda: "zh_TW")
+
+    assert usage_statusline._statusline_detect_lang({}) == "en"
+    assert usage_statusline._statusline_detect_lang() == "zh-TW"
+
+
+def test_statusline_detect_lang_prefers_usage_lang_over_windows_system_lang(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(usage_statusline, "_windows_system_lang", lambda: "zh_TW")
+
+    assert usage_statusline._statusline_detect_lang({"USAGE_LANG": "ja"}) == "ja"
+
+
+def test_statusline_windows_system_lang_is_empty_off_windows(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setattr(usage_statusline, "os", SimpleNamespace(name="posix"))
+
+    assert usage_statusline._windows_system_lang() == ""
+
+
 def test_windows_output_reconfigures_both_streams(monkeypatch: pytest.MonkeyPatch) -> None:
     class Stream:
         def __init__(self) -> None:
@@ -411,6 +494,26 @@ def test_main_writes_valid_json_object(
     assert capsys.readouterr().out == "usage\n"
 
 
+def test_main_reads_utf8_bytes_when_stdin_uses_cp950(
+    monkeypatch: pytest.MonkeyPatch,
+    tmp_path: Path,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    status_file = tmp_path / "usage-status.json"
+    payload = {"cwd": r"C:\\Users\\USER\\Desktop\\GitHub專案\\usage"}
+    stdin = io.TextIOWrapper(
+        io.BytesIO(json.dumps(payload, ensure_ascii=False).encode("utf-8")), encoding="cp950"
+    )
+    monkeypatch.setattr(usage_statusline, "STATUS_FILE", str(status_file))
+    monkeypatch.setattr(usage_statusline, "LOCK_FILE", str(tmp_path / "usage-status.lock"))
+    monkeypatch.setattr(sys, "stdin", stdin)
+
+    usage_statusline.main()
+
+    assert json.loads(status_file.read_text(encoding="utf-8"))["cwd"] == payload["cwd"]
+    assert capsys.readouterr().out == "usage\n"
+
+
 def test_main_returns_when_stdin_read_raises(
     monkeypatch: pytest.MonkeyPatch,
     tmp_path: Path,