Let the incr and decr stubs accept default=None

CHANGELOG.md

@@ -2,6 +2,12 @@
 
 diskcache-community forked from DiskCache at upstream commit ebfa37c (3 March 2024), two commits after the 5.6.3 release. Each entry names the pull request in this repository. Imported upstream pull requests are referenced by number, and their commits keep their original authors in the git history.
 
+## Unreleased
+
+### Fixes
+
+- `incr` and `decr` on `Cache` and `FanoutCache` type-check with `default=None`, which makes a missing key raise `KeyError`: the stubs typed `default` as `int`, so type checkers rejected the call. `tox -e mypy` now also checks `tests/typecheck_stubs.py`, a file of calls that must type-check against the stubs (PR #41).
+
 ## 5.8.2 (2026-11-02)
 
 Adds `SafeJSONDisk` and `SafeDisk.with_numpy()`, keeps float NaN values, and makes `get` and `set` faster. The `cache.db` schema and the file layout are unchanged.

diskcache_community/_types.pyi

@@ -173,10 +173,18 @@ class BaseCache(Protocol):
         retry: bool = ...,
     ) -> bool: ...
     def incr(
-        self, key: Any, delta: int = ..., default: int = ..., retry: bool = ...
+        self,
+        key: Any,
+        delta: int = ...,
+        default: int | None = ...,
+        retry: bool = ...,
     ) -> int: ...
     def decr(
-        self, key: Any, delta: int = ..., default: int = ..., retry: bool = ...
+        self,
+        key: Any,
+        delta: int = ...,
+        default: int | None = ...,
+        retry: bool = ...,
     ) -> int: ...
     def get(  # noqa: PLR0913
         self,

tests/typecheck_stubs.py

@@ -0,0 +1,22 @@
+"""Calls that must type-check against the shipped stubs.
+
+``tox -e mypy`` checks this file; pytest does not collect it.
+"""
+
+import diskcache_community as dc
+
+
+def incr_without_default(cache: dc.Cache, key: str) -> int:
+    return cache.incr(key, 1, default=None)
+
+
+def decr_without_default(cache: dc.Cache, key: str) -> int:
+    return cache.decr(key, 1, default=None)
+
+
+def fanout_incr_without_default(cache: dc.FanoutCache, key: str) -> int:
+    return cache.incr(key, 1, default=None)
+
+
+def fanout_decr_without_default(cache: dc.FanoutCache, key: str) -> int:
+    return cache.decr(key, 1, default=None)

tox.ini

@@ -45,7 +45,7 @@ commands=isort --check {toxinidir}/diskcache_community {toxinidir}/tests
 deps=isort
 
 [testenv:mypy]
-commands=mypy {toxinidir}/diskcache_community
+commands=mypy {toxinidir}/diskcache_community {toxinidir}/tests/typecheck_stubs.py
 deps=mypy
 
 [testenv:pylint]