From 3e61311772133fd4f3645dab01de836e04a97bf8 Mon Sep 17 00:00:00 2001
From: Frederik Hennig <frederik.hennig@fau.de>
Date: Fri, 5 Apr 2024 12:58:32 +0200
Subject: [PATCH] Weakened type uniquing: Pickle may now create its own
instances
---
src/pystencils/types/meta.py | 33 +++++++++++++-----------------
tests/nbackend/types/test_types.py | 1 -
2 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/src/pystencils/types/meta.py b/src/pystencils/types/meta.py
index 198abf0ec..02c2f5a3b 100644
--- a/src/pystencils/types/meta.py
+++ b/src/pystencils/types/meta.py
@@ -27,7 +27,7 @@ For this to work, all instantiable subclasses of `PsType` must implement the fol
arguments in their canonical order. This method is used by `PsTypeMeta` to identify instances,
and to catch the various different possibilities Python offers for passing function arguments.
- The ``__args__`` method, when called on an instance of the type, must return a tuple containing the constructor
- arguments required to create that exact instance. This is used for pickling and unpickling of type objects,
+ arguments required to create that exact instance. This is used for comparing type objects
as well as const-conversion.
As a rule, ``MyType.__canonical_args__(< arguments >)`` and ``MyType(< arguments >).__args__()`` must always return
@@ -81,27 +81,11 @@ class PsType(metaclass=PsTypeMeta):
# Internals: Object creation, pickling and unpickling
# -------------------------------------------------------------------------------------------
- def __new__(cls, *args, _pickle=False, **kwargs):
- if _pickle:
- # force unpickler to use metaclass uniquing mechanism
- return cls(*args, **kwargs)
- else:
- return super().__new__(cls)
-
- def __getnewargs_ex__(self):
- args = self.__args__()
- kwargs = {"const": self._const, "_pickle": True}
- return args, kwargs
-
- def __getstate__(self):
- # To make sure pickle does not unnecessarily override the instance dictionary
- return None
-
@abstractmethod
def __args__(self) -> tuple[Any, ...]:
"""Return the arguments used to create this instance, in canonical order, excluding the const-qualifier.
- The tuple returned by this method is used to serialize, deserialize, and const-convert types.
+ The tuple returned by this method is used to identify, check equality, and const-convert types.
For each instantiable subclass ``MyType`` of ``PsType``, the following must hold::
t = MyType(< arguments >)
@@ -115,7 +99,18 @@ class PsType(metaclass=PsTypeMeta):
"""Return a tuple containing the positional and keyword arguments of ``__init__``
in their canonical order."""
- # __eq__ and __hash__ unimplemented because due to uniquing, types are equal iff their instances are equal
+ def __eq__(self, other: object) -> bool:
+ if self is other:
+ return True
+
+ if type(self) is not type(other):
+ return False
+
+ other = cast(PsType, other)
+ return self.const == other.const and self.__args__() == other.__args__()
+
+ def __hash__(self) -> int:
+ return hash((type(self), self.const, self.__args__()))
# -------------------------------------------------------------------------------------------
# Constructor and properties
diff --git a/tests/nbackend/types/test_types.py b/tests/nbackend/types/test_types.py
index 65cbf9d08..39f89e6fe 100644
--- a/tests/nbackend/types/test_types.py
+++ b/tests/nbackend/types/test_types.py
@@ -163,4 +163,3 @@ def test_pickle():
for t1, t2 in zip(types, restored):
assert t1 == t2
- assert t1 is t2
--
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