`CacheRegion.configure` should return `typing_extensions.Self`

[Daverball]

dogpile.cache/dogpile/cache/region.py

Line 429 in 96b8b28

) -> "CacheRegion":

Returning a fixed type here is unfriendly to subclassing CacheRegion to e.g. add new methods.

[zzzeek]

sure, you can see the blame on there is three years ago before pep-673 was even posted. send a PR

[Daverball]

Before that it would've still been possible using def method(self: _T) -> _T: But I agree that it is a little bit more cumbersome to use a TypeVar.

[zzzeek]

to clarify, pep-673 provides the Self type. this code should be changed as follows:

diff --git a/dogpile/cache/region.py b/dogpile/cache/region.py
index 79f7eaa..952f245 100644
--- a/dogpile/cache/region.py
+++ b/dogpile/cache/region.py
@@ -18,6 +18,7 @@ from typing import Sequence
 from typing import Tuple
 from typing import Type
 from typing import Union
+from typing_extensions import Self
 
 from decorator import decorate
 
@@ -426,7 +427,7 @@ class CacheRegion:
         wrap: Sequence[Union[ProxyBackend, Type[ProxyBackend]]] = (),
         replace_existing_backend: bool = False,
         region_invalidator: Optional[RegionInvalidationStrategy] = None,
-    ) -> "CacheRegion":
+    ) -> Self:
         """Configure a :class:`.CacheRegion`.
 
         The :class:`.CacheRegion` itself
diff --git a/setup.cfg b/setup.cfg
index 319c4b9..3efb2ce 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -24,6 +24,7 @@ project_urls =
 install_requires =
   decorator>=4.0.0
   stevedore>=3.0.0
+  typing_extensions
 zip_safe = False
 packages = find:
 python_requires = >=3.6

[zzzeek]

oh, yes, we used to use TypeVar for this kind of thing but that didn't become apparent to me until I had 100's of such methods to do in SQLAlchemy, and even then it had some rough edges

[sqla-tester]

Viicos has proposed a fix for this issue in the main branch:

Use typing.Self https://gerrit.sqlalchemy.org/c/sqlalchemy/dogpile.cache/+/4739

[sqla-tester]

Viicos has proposed a fix for this issue in the main branch:

Use typing.Self https://gerrit.sqlalchemy.org/c/sqlalchemy/dogpile.cache/+/4739