dependency: define equality and hash operators for Dependency

When a dependency is copied and its name is changed, we still need a way
to say "this is the same dependency", which we now have. It is
important, however, when a partial dependency is created that dependency
does *not* match the original dependency, since they are not providing
the same data. This was always happening for InternalDependencies as an
implementation detail, but not for other kinds.

mesonbuild/dependencies/base.py

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 # Copyright 2013-2018 The Meson development team
+# Copyright © 2024 Intel Corporation
 
 # This file contains the detection logic for external dependencies.
 # Custom logic for several other packages are in separate files.
@@ -10,6 +11,7 @@ import os
 import collections
 import itertools
 import typing as T
+import uuid
 from enum import Enum
 
 from .. import mlog, mesonlib
@@ -106,6 +108,9 @@ class Dependency(HoldableObject):
         return kwargs['include_type']
 
     def __init__(self, type_name: DependencyTypeName, kwargs: T.Dict[str, T.Any]) -> None:
+        # This allows two Dependencies to be compared even after being copied.
+        # The purpose is to allow the name to be changed, but still have a proper comparison
+        self._id = uuid.uuid4().int
         self.name = f'dep{id(self)}'
         self.version:  T.Optional[str] = None
         self.language: T.Optional[str] = None # None means C-like
@@ -124,6 +129,14 @@ class Dependency(HoldableObject):
         self.featurechecks: T.List['FeatureCheckBase'] = []
         self.feature_since: T.Optional[T.Tuple[str, str]] = None
 
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, Dependency):
+            return NotImplemented
+        return self._id == other._id
+
+    def __hash__(self) -> int:
+        return self._id
+
     def __repr__(self) -> str:
         return f'<{self.__class__.__name__} {self.name}: {self.is_found}>'
 
@@ -402,6 +415,7 @@ class ExternalDependency(Dependency, HasNativeKwarg):
                                link_args: bool = False, links: bool = False,
                                includes: bool = False, sources: bool = False) -> Dependency:
         new = copy.copy(self)
+        new._id = uuid.uuid4().int
         if not compile_args:
             new.compile_args = []
         if not link_args:
@@ -472,7 +486,9 @@ class NotFoundDependency(Dependency):
     def get_partial_dependency(self, *, compile_args: bool = False,
                                link_args: bool = False, links: bool = False,
                                includes: bool = False, sources: bool = False) -> 'NotFoundDependency':
-        return copy.copy(self)
+        new = copy.copy(self)
+        new._id = uuid.uuid4().int
+        return new
 
 
 class ExternalLibrary(ExternalDependency):
@@ -512,6 +528,7 @@ class ExternalLibrary(ExternalDependency):
         # External library only has link_args, so ignore the rest of the
         # interface.
         new = copy.copy(self)
+        new._id = uuid.uuid4().int
         if not link_args:
             new.link_args = []
         return new