fix: harden server start/stop guards

1 files changed, 43 insertions, 25 deletions

diff --git a/app/backends/common.py b/app/backends/common.py
index 10b4ccf..9b6232a 100644
--- a/app/backends/common.py
+++ b/app/backends/common.py
@@ -102,12 +102,19 @@ def resolve_wav_dir_arg(value: str) -> Path:
 
 
 def find_wav_files(input_dir: Path) -> List[Path]:
-    """Return the .wav files in INPUT_DIR, sorted alphabetically by name."""
-    return sorted(
-        (path for path in input_dir.iterdir()
-         if path.is_file() and path.suffix.lower() == ".wav"),
-        key=lambda path: path.name.lower(),
-    )
+    """Return the .wav files in INPUT_DIR, sorted alphabetically by name.
+
+    A missing or unreadable directory yields [] so callers can treat it
+    like an empty directory (matching ``count_wavs``).
+    """
+    try:
+        return sorted(
+            (path for path in input_dir.iterdir()
+             if path.is_file() and path.suffix.lower() == ".wav"),
+            key=lambda path: path.name.lower(),
+        )
+    except OSError:
+        return []
 
 
 def count_wavs(directory: Path) -> int:
@@ -248,29 +255,38 @@ def server_running(url: str, timeout: float = 0.3) -> bool:
         return False
 
 
-def update_config_value(key: str, value: str,
+def update_config_value(key: str, value,
                         config_path: Optional[Path] = None) -> bool:
-    """Rewrite a ``KEY = "value"`` line in app/converter/config.py.
-
-    Only the quoted literal is replaced; surrounding lines and the trailing
-    comment are preserved. Returns True when the file was changed. Used by
-    the qwen and faster wizards to keep their API URL / voice / speaker
-    settings in sync with the converter.
+    """Set ``KEY`` to VALUE in app/converter/config.py and in memory.
+
+    Only the value of the named assignment changes: indentation and any
+    trailing comment are preserved. Strings render double-quoted; other
+    literals (ints, booleans) render bare. After a successful write (or
+    when the file already holds VALUE) the new value is mirrored onto the
+    imported ``converter.config`` module, so a wizard's change takes
+    effect immediately instead of only after the next process start.
+    Returns True when the file now holds VALUE, False when it could not
+    be read or written (or KEY has no line in it).
     """
     path = Path(config_path) if config_path is not None else CONFIG_PATH
+    rendered = f'"{value}"' if isinstance(value, str) else str(value)
     try:
         text = path.read_text(encoding="utf-8")
+        match = re.search(
+            rf'(?m)^(\s*{re.escape(key)}\s*=\s*)("[^"]*"|\S+)(\s*(?:#.*)?)$',
+            text)
+        if match is None:
+            return False
+        if match.group(2) != rendered:
+            text = text[:match.start(2)] + rendered + text[match.end(2):]
+            path.write_text(text, encoding="utf-8")
     except OSError:
         return False
-    match = re.search(r'(?m)^(\s*' + re.escape(key) + r'\s*=\s*")([^"]*)(")',
-                      text)
-    if not match or match.group(2) == value:
-        return False
-    text = text[:match.start(2)] + value + text[match.end(2):]
-    try:
-        path.write_text(text, encoding="utf-8")
-    except OSError:
-        return False
+    # Local import: this module must stay importable before the venv
+    # exists (backends.envs bootstraps from it), and converter.config is
+    # stdlib-only constants, safe to load whenever a wizard runs.
+    from converter import config as _config
+    setattr(_config, key, value)
     return True
 
 
@@ -458,16 +474,18 @@ def git_clone(url: str, target: Path, *, emit=None, cancel=None) -> int:
         emit=emit, cancel=cancel)
 
 
-def pip_install(packages: List[str]) -> int:
+def pip_install(packages: List[str], *, emit=None, cancel=None) -> int:
     """pip install PACKAGES into the managed venv (``envs/tts``). Returns exit code.
 
     Delegates to ``backends.envs.pip_install`` so backend TTS packages are
     installed alongside the app requirements in the tool-managed environment
     rather than into whatever interpreter happens to be running the wizard.
-    The import is local to avoid a circular import (envs imports this module).
+    With EMIT given (the in-TUI task view) pip runs with its output streamed
+    into EMIT; CANCEL aborts it. The import is local to avoid a circular
+    import (envs imports this module).
     """
     from backends import envs
-    return envs.pip_install(packages)
+    return envs.pip_install(packages, emit=emit, cancel=cancel)
 
 
 def pip_uninstall(packages: List[str], *, emit=None) -> int: