Update typing for Flask 3.0; drop Python 3.7 and 3.8 (#418)

.github/workflows/pytest.yml

@@ -19,7 +19,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
+        python-version: ['3.9', '3.10', '3.11', '3.12']
 
     services:
       redis:

.pre-commit-config.yaml

@@ -25,8 +25,7 @@ repos:
     rev: v3.15.0
     hooks:
       - id: pyupgrade
-        args:
-          ['--keep-runtime-typing', '--py3-plus', '--py36-plus', '--py37-plus']
+        args: ['--keep-runtime-typing', '--py39-plus']
   - repo: https://github.com/asottile/yesqa
     rev: v1.5.0
     hooks:

CHANGES.rst

@@ -1,8 +1,8 @@
-0.7.0 - 2022-05-XX
+0.7.0 - Unreleased
 ------------------
 
 * Dropped Python 2.7 support
-* Dropped Python 3.6 support as it lacks typing annotations; 3.7+ is now
+* Dropped Python 3.6 support as it lacks typing annotations; 3.9+ is now
   required
 * Removed deprecated ``docflow`` module. ``StateManager`` replaces it
 * Removed deprecated ``make_password`` and ``check_password`` functions
@@ -30,7 +30,7 @@
 * Coaster now uses ``src`` folder layout and has project metadata defined in
   ``pyproject.toml`` as per PEP 660, requiring setuptools>=61
 * Added ``coaster.app.JSONProvider`` that supports the ``__json__`` protocol
-* Now compatible with Flask 2.2 and 2.3
+* Now compatible with Flask 2.3 and 3.0
 * UgliPyJS is no longer offered as a Webassets filter as the dependency is
   unmaintained, and usage is shifting from Webassets to Webpack
 * ``for_tsquery`` has been removed as PostgreSQL>=12 has native functions

README.rst

@@ -5,7 +5,7 @@ Coaster: common patterns for Flask apps
 
 Coaster contains functions and db models for recurring patterns in Flask
 apps. Documentation is at https://coaster.readthedocs.org/. Coaster requires
-Python 3.7 or later.
+Python 3.9 or later.
 
 
 Run tests

pyproject.toml

@@ -9,7 +9,7 @@ build-backend = 'setuptools.build_meta'
 name = 'coaster'
 description = 'Coaster for Flask'
 readme = 'README.rst'
-requires-python = '>=3.7'
+requires-python = '>=3.9'
 keywords = ['coaster', 'flask', 'framework', 'web', 'auth', 'sqlalchemy']
 license = { file = 'LICENSE.txt' }
 dynamic = ['version']
@@ -19,11 +19,10 @@ urls = { repository = 'https://github.com/hasgeek/coaster' }
 classifiers = [
   'Programming Language :: Python',
   'Programming Language :: Python :: 3 :: Only',
-  'Programming Language :: Python :: 3.7',
-  'Programming Language :: Python :: 3.8',
   'Programming Language :: Python :: 3.9',
   'Programming Language :: Python :: 3.10',
   'Programming Language :: Python :: 3.11',
+  'Programming Language :: Python :: 3.12',
   'Framework :: Flask',
   'License :: OSI Approved :: BSD License',
   'Operating System :: OS Independent',
@@ -40,7 +39,7 @@ dependencies = [
   'Flask-Assets2',
   'Flask-Migrate',
   'Flask-SQLAlchemy',
-  'Flask>=2.2',
+  'Flask>=2.3',
   'furl',
   'html5lib>=0.999999999',
   'isoweek',
@@ -66,7 +65,7 @@ where = ['src']
 
 [tool.black]
 line-length = 88
-target_version = ['py36']
+target_version = ['py39']
 skip-string-normalization = true
 include = '\.pyi?$'
 exclude = '''
@@ -104,7 +103,7 @@ sections = ['FUTURE', 'STDLIB', 'THIRDPARTY', 'FIRSTPARTY', 'LOCALFOLDER']
 
 [tool.pytest.ini_options]
 pythonpath = 'src'
-required_plugins = ['pytest-env', 'pytest-rerunfailures', 'pytest-remotedata']
+required_plugins = ['pytest-env', 'pytest-rerunfailures', 'pytest-socket']
 minversion = '6.0'
 addopts = '--doctest-modules --ignore setup.py --cov-report=term-missing'
 doctest_optionflags = ['ALLOW_UNICODE', 'ALLOW_BYTES']
@@ -176,9 +175,8 @@ skips = ['*/*_test.py', '*/test_*.py']
 
 [tool.ruff]
 # This is a slight customisation of the default rules
-# 1. Coaster still supports Python 3.7 pending its EOL
-# 2. Rule E402 (module-level import not top-level) is disabled as isort handles it
-# 3. Rule E501 (line too long) is left to Black; some strings are worse for wrapping
+# 1. Rule E402 (module-level import not top-level) is disabled as isort handles it
+# 2. Rule E501 (line too long) is left to Black; some strings are worse for wrapping
 
 # Enable pycodestyle (`E`) and Pyflakes (`F`) codes by default.
 select = ["E", "F"]
@@ -263,8 +261,8 @@ line-length = 88
 # Allow unused variables when underscore-prefixed.
 dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
 
-# Target Python 3.7
-target-version = "py37"
+# Target Python 3.9
+target-version = "py39"
 
 [tool.ruff.mccabe]
 # Unlike Flake8, default to a complexity level of 10.

src/coaster/app.py

@@ -14,10 +14,14 @@
 from typing import NamedTuple, cast
 
 import itsdangerous
-from flask import Flask
 from flask.json.provider import DefaultJSONProvider
 from flask.sessions import SecureCookieSessionInterface
 
+try:  # Flask >= 3.0
+    from flask.sansio.app import App as FlaskApp
+except ModuleNotFoundError:  # Flask < 3.0
+    from flask import Flask as FlaskApp
+
 from . import logger
 from .auth import current_auth
 from .views import current_view
@@ -162,7 +166,7 @@ class RotatingKeySecureCookieSessionInterface(SecureCookieSessionInterface):
     """Replaces the serializer with key rotation support."""
 
     def get_signing_serializer(  # type: ignore[override]
-        self, app: Flask
+        self, app: FlaskApp
     ) -> t.Optional[KeyRotationWrapper]:
         """Return serializers wrapped for key rotation."""
         if not app.config.get('SECRET_KEYS'):
@@ -201,7 +205,7 @@ def default(o: t.Any) -> t.Any:
 
 
 def init_app(
-    app: Flask,
+    app: FlaskApp,
     config: t.Optional[t.List[te.Literal['env', 'py', 'json', 'toml', 'yaml']]] = None,
     *,
     env_prefix: t.Optional[t.Union[str, t.Sequence[str]]] = None,
@@ -240,7 +244,7 @@ def init_app(
 
     .. note::
         YAML support requires PyYAML_. TOML requires toml_ with Flask 2.2, or tomli_
-        with Flask 2.3, or Python's inbuilt tomllib_ with Flask 2.3 and Python 3.11.
+        with Flask 2.3, or Python's inbuilt tomllib_ with Flask 2.3 and Python 3.11+.
         tomli_ and tomllib_ are not compatible with Flask 2.2 as they require the file
         to be opened in binary mode, an optional flag introduced in Flask 2.3.
 
@@ -317,7 +321,7 @@ def init_app(
 
 
 def load_config_from_file(
-    app: Flask,
+    app: FlaskApp,
     filepath: str,
     load: t.Optional[t.Callable] = None,
     text: t.Optional[bool] = None,

src/coaster/assets.py

@@ -141,6 +141,8 @@ def _require_recursive(self, *namespecs: str) -> t.List[t.Tuple[str, Version, st
                         )
                 else:
                     asset = self[name][version]
+                    requires: t.Union[t.List[str], t.Tuple[str, ...], str]
+                    provides: t.Union[t.List[str], t.Tuple[str, ...], str]
                     if isinstance(asset, (list, tuple)):
                         # We have (requires, bundle). Get requirements
                         requires = asset[:-1]

src/coaster/logger.py

@@ -29,9 +29,14 @@
     from logging import _SysExcInfoType
 
 import requests
-from flask import Flask, g, request, session
+from flask import g, request, session
 from flask.config import Config
 
+try:  # Flask >= 3.0
+    from flask.sansio.app import App as FlaskApp
+except ModuleNotFoundError:
+    from flask import Flask as FlaskApp
+
 from .auth import current_auth
 
 # Regex for credit card numbers
@@ -432,7 +437,7 @@ def emit(self, record: logging.LogRecord) -> None:
 }
 
 
-def init_app(app: Flask, _warning_stacklevel: int = 2) -> None:
+def init_app(app: FlaskApp, _warning_stacklevel: int = 2) -> None:
     """
     Enable logging for an app using :class:`LocalVarFormatter`.
 

src/coaster/sqlalchemy/functions.py

@@ -6,6 +6,7 @@
 from __future__ import annotations
 
 import typing as t
+from datetime import datetime
 from typing import cast, overload
 
 import sqlalchemy as sa
@@ -63,37 +64,40 @@ def _utcnow_mssql(  # pragma: no cover
 
 def make_timestamp_columns(
     timezone: bool = False,
-) -> t.Iterable[sa.Column[sa.TIMESTAMP]]:
+) -> t.Tuple[sa.Column[datetime], sa.Column[datetime]]:
     """Return two columns, `created_at` and `updated_at`, with appropriate defaults."""
     return (
         sa.Column(
             'created_at',
-            sa.TIMESTAMP(timezone=timezone),  # type: ignore[arg-type]
+            sa.TIMESTAMP(timezone=timezone),
             default=sa.func.utcnow(),
             nullable=False,
         ),
         sa.Column(
             'updated_at',
-            sa.TIMESTAMP(timezone=timezone),  # type: ignore[arg-type]
+            sa.TIMESTAMP(timezone=timezone),
             default=sa.func.utcnow(),
             onupdate=sa.func.utcnow(),
             nullable=False,
         ),
     )
 
 
+session_type = t.Union[sa.orm.Session, sa.orm.scoped_session]
+
+
 @overload
-def failsafe_add(__session: sa.orm.Session, __instance: t.Any) -> None:
+def failsafe_add(__session: session_type, __instance: t.Any) -> None:
     ...
 
 
 @overload
-def failsafe_add(__session: sa.orm.Session, __instance: T, **filters: t.Any) -> T:
+def failsafe_add(__session: session_type, __instance: T, **filters: t.Any) -> T:
     ...
 
 
 def failsafe_add(
-    __session: sa.orm.Session, __instance: T, **filters: t.Any
+    __session: session_type, __instance: T, **filters: t.Any
 ) -> t.Optional[T]:
     """
     Add and commit a new instance in a nested transaction (using SQL SAVEPOINT).

src/coaster/sqlalchemy/mixins.py

@@ -30,8 +30,14 @@ class MyModel(BaseMixin, db.Model):
 from typing import cast, overload
 from uuid import UUID, uuid4
 
+from flask import current_app, url_for
+
+try:  # Flask >= 3.0
+    from flask.sansio.app import App as FlaskApp
+except ModuleNotFoundError:  # Flask < 3.0
+    from flask import Flask as FlaskApp
+
 import sqlalchemy as sa
-from flask import Flask, current_app, url_for
 from sqlalchemy import event
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy.orm import Mapped, declarative_mixin, declared_attr, synonym
@@ -385,11 +391,11 @@ class UrlForMixin:
     #: app may also be None as fallback. Each subclass will get its own dictionary.
     #: This particular dictionary is only used as an inherited fallback.
     url_for_endpoints: t.ClassVar[
-        t.Dict[t.Optional[Flask], t.Dict[str, UrlEndpointData]]
+        t.Dict[t.Optional[FlaskApp], t.Dict[str, UrlEndpointData]]
     ] = {None: {}}
     #: Mapping of {app: {action: (classview, attr)}}
     view_for_endpoints: t.ClassVar[
-        t.Dict[t.Optional[Flask], t.Dict[str, t.Tuple[t.Any, str]]]
+        t.Dict[t.Optional[FlaskApp], t.Dict[str, t.Tuple[t.Any, str]]]
     ] = {}
 
     #: Dictionary of URLs available on this object
@@ -448,7 +454,7 @@ def is_url_for(
         cls,
         _action: str,
         _endpoint: t.Optional[str] = None,
-        _app: t.Optional[Flask] = None,
+        _app: t.Optional[FlaskApp] = None,
         _external: t.Optional[bool] = None,
         **paramattrs: t.Union[str, t.Tuple[str, ...], t.Callable[[t.Any], str]],
     ) -> ReturnDecorator:
@@ -479,7 +485,7 @@ def register_endpoint(
         cls,
         action: str,
         endpoint: str,
-        app: t.Optional[Flask],
+        app: t.Optional[FlaskApp],
         paramattrs: t.Mapping[
             str, t.Union[str, t.Tuple[str, ...], t.Callable[[t.Any], str]]
         ],
@@ -522,7 +528,7 @@ def register_endpoint(
 
     @classmethod
     def register_view_for(
-        cls, app: t.Optional[Flask], action: str, classview: t.Any, attr: str
+        cls, app: t.Optional[FlaskApp], action: str, classview: t.Any, attr: str
     ) -> None:
         """Register a classview and viewhandler for a given app and action."""
         if 'view_for_endpoints' not in cls.__dict__:

src/coaster/sqlalchemy/roles.py

@@ -647,6 +647,8 @@ def __repr__(self) -> str:
 
     def __contains__(self, value: t.Any) -> bool:
         relattr = self.relattr
+        if t.TYPE_CHECKING:
+            assert relattr.session is not None  # nosec B101
         return relattr.session.query(
             relattr.filter_by(**{self.attr: value}).exists()
         ).scalar()
@@ -660,6 +662,8 @@ def __len__(self) -> int:
 
     def __bool__(self) -> bool:
         relattr = self.relattr
+        if t.TYPE_CHECKING:
+            assert relattr.session is not None  # nosec B101
         return relattr.session.query(relattr.exists()).scalar()
 
     def __eq__(self, other: t.Any) -> bool: