Specify that gettext functions require a LiteralString; other fixes

.pre-commit-config.yaml

@@ -111,6 +111,12 @@ repos:
     hooks:
       - id: reformat-gherkin
         files: \.feature$
+  - repo: https://github.com/shellcheck-py/shellcheck-py
+    rev: v0.9.0.6
+    hooks:
+      - id: shellcheck
+        args:
+          - --external-sources
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.5.0
     hooks:

pyproject.toml

@@ -122,8 +122,8 @@ ignore_missing_imports = true
 show_error_codes = true
 warn_unreachable = true
 warn_unused_ignores = true
-warn_redundant_casts = false
-check_untyped_defs = false
+warn_redundant_casts = true
+check_untyped_defs = true
 
 [tool.pytest.ini_options]
 pythonpath = 'src'

src/baseframe/__init__.py

@@ -1,6 +1,6 @@
 """Baseframe init."""
 
-from typing import Callable, cast
+from typing import cast
 
 from flask_babel import gettext, lazy_gettext
 
@@ -9,15 +9,16 @@
 from .blueprint import *  # NOQA
 from .deprecated import *  # NOQA
 from .extensions import *  # NOQA
+from .extensions import GetTextProtocol
 from .filters import *  # NOQA
 from .utils import *  # NOQA
 from .views import *  # NOQA
 
 from . import forms  # isort:skip
 
 # Pretend these return str, not Any or LazyString
-_ = cast(Callable[..., str], gettext)
-__ = cast(Callable[..., str], lazy_gettext)
+_ = cast(GetTextProtocol, gettext)
+__ = cast(GetTextProtocol, lazy_gettext)
 
 # TODO: baseframe_js and baseframe_css are defined in deprecated.py
 # and pending removal after an audit of all apps

src/baseframe/extensions.py

@@ -3,6 +3,7 @@
 
 import os.path
 import typing as t
+import typing_extensions as te
 from datetime import tzinfo
 from typing import cast
 
@@ -37,6 +38,18 @@
 ]
 
 
+class GetTextProtocol(te.Protocol):
+    """
+    Callable protocol for gettext and lazy_gettext.
+
+    Specify that the first parameter must always be a literal string, not a variable,
+    and that the return type is a string (though actually a LazyString).
+    """
+
+    def __call__(self, string: te.LiteralString, **variables) -> str:
+        ...
+
+
 DEFAULT_LOCALE = 'en'
 
 networkbar_cache = Cache(with_jinja2_ext=False)
@@ -52,8 +65,8 @@
 baseframe_translations = Domain(
     os.path.join(os.path.dirname(__file__), 'translations'), domain='baseframe'
 )
-_ = cast(t.Callable[..., str], baseframe_translations.gettext)
-__ = cast(t.Callable[..., str], baseframe_translations.lazy_gettext)
+_ = cast(GetTextProtocol, baseframe_translations.gettext)
+__ = cast(GetTextProtocol, baseframe_translations.lazy_gettext)
 
 
 def get_user_locale() -> str:

src/baseframe/forms/validators.py

@@ -80,8 +80,10 @@
 }
 
 InvalidUrlPatterns = t.Iterable[t.Tuple[t.Iterable[t.Any], str]]
-AllowedListInit = t.Union[t.Iterable[str], t.Callable[[], t.Iterable[str]], None]
-AllowedList = t.Union[t.Iterable[str], None]
+AllowedListInit = t.Optional[
+    t.Union[t.Iterable[str], t.Callable[[], t.Optional[t.Iterable[str]]]]
+]
+AllowedList = t.Optional[t.Iterable[str]]
 
 
 def is_empty(value: t.Any) -> bool: