Use siphash for persistent hashing

.pylintrc-local.yml

@@ -4,3 +4,4 @@
 - arg: ignored-modules
   val:
   - matplotlib
+  - siphash24

pyproject.toml

@@ -33,6 +33,7 @@ classifiers = [
 dependencies = [
     "platformdirs>=2.2",
     "typing-extensions>=4; python_version<'3.11'",
+    "siphash24",
 ]
 
 [project.optional-dependencies]

pytools/persistent_dict.py

@@ -30,7 +30,6 @@
 """
 
 
-import hashlib
 import logging
 import os
 import pickle
@@ -52,6 +51,8 @@
     cast,
 )
 
+from siphash24 import siphash13
+
 
 if TYPE_CHECKING:
     from _typeshed import ReadableBuffer
@@ -160,7 +161,7 @@ class KeyBuilder:
 
     # this exists so that we can (conceivably) switch algorithms at some point
     # down the road
-    new_hash: Callable[..., Hash] = hashlib.sha256
+    new_hash: Callable[..., Hash] = siphash13
 
     def rec(self, key_hash: Hash, key: Any) -> Hash:
         """
@@ -301,7 +302,8 @@ def update_for_frozenset(self, key_hash: Hash, key: FrozenSet[Any]) -> None:
 
         unordered_hash(
             key_hash,
-            (self.rec(self.new_hash(), key_i).digest() for key_i in key))
+            (self.rec(self.new_hash(), key_i).digest() for key_i in key),
+            hash_constructor=self.new_hash)
 
     update_for_FrozenOrderedSet = update_for_frozenset  # noqa: N815
 
@@ -351,7 +353,8 @@ def update_for_frozendict(self, key_hash: Hash, key: Mapping[Any, Any]) -> None:
 
         unordered_hash(
             key_hash,
-            (self.rec(self.new_hash(), (k, v)).digest() for k, v in key.items()))
+            (self.rec(self.new_hash(), (k, v)).digest() for k, v in key.items()),
+            hash_constructor=self.new_hash)
 
     update_for_immutabledict = update_for_frozendict
     update_for_constantdict = update_for_frozendict