deprecate __version__ attribute (#1256)

Author: davidism

CHANGES.rst

@@ -1,7 +1,16 @@
+Version 3.1.1
+-------------
+
+Unreleased
+
+-   Deprecate the ``__version__`` attribute. Use feature detection, or
+    ``importlib.metadata.version("flask-sqlalchemy")``, instead. :issue:`5230`
+
+
 Version 3.1.0
 -------------
 
-Released 2023-09-10
+Released 2023-09-11
 
 -   Drop support for Python 3.7.  :pr:`1251`
 -   Add support for the SQLAlchemy 2.x API via ``model_class`` parameter. :issue:`1140`

pyproject.toml

@@ -1,5 +1,6 @@
 [project]
 name = "Flask-SQLAlchemy"
+version = "3.1.1.dev"
 description = "Add SQLAlchemy support to your Flask application."
 readme = "README.rst"
 license = { file = "LICENSE.rst" }
@@ -18,7 +19,6 @@ dependencies = [
     "flask>=2.2.5",
     "sqlalchemy>=2.0.16",
 ]
-dynamic = ["version"]
 
 [project.urls]
 Donate = "https://palletsprojects.com/donate"

src/flask_sqlalchemy/__init__.py

@@ -1,9 +1,26 @@
 from __future__ import annotations
 
-from .extension import SQLAlchemy
+import typing as t
 
-__version__ = "3.1.0"
+from .extension import SQLAlchemy
 
 __all__ = [
     "SQLAlchemy",
 ]
+
+
+def __getattr__(name: str) -> t.Any:
+    if name == "__version__":
+        import importlib.metadata
+        import warnings
+
+        warnings.warn(
+            "The '__version__' attribute is deprecated and will be removed in"
+            " Flask-SQLAlchemy 3.2. Use feature detection or"
+            " 'importlib.metadata.version(\"flask-sqlalchemy\")' instead.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return importlib.metadata.version("flask-sqlalchemy")
+
+    raise AttributeError(name)