E721: Do not compare types, use 'isinstance()'

ref pantsbuild#21647

build-support/flake8/.flake8

@@ -17,9 +17,7 @@ extend-ignore:
   # Implicitly concatenated bytes literals over multiple lines
   NIC102,
   # Unnecessary dict call - rewrite as a literal
-  C408,
-  # Temporarily exclude during Python upgrade
-  E721
+  C408
 
 [flake8:local-plugins]
 extension =

src/python/pants/backend/python/util_rules/package_dists_test.py

@@ -172,7 +172,7 @@ def assert_chroot_error(
         )
     ex = excinfo.value
     assert len(ex.wrapped_exceptions) == 1
-    assert type(ex.wrapped_exceptions[0]) == exc_cls
+    assert type(ex.wrapped_exceptions[0]) is exc_cls
 
 
 def test_use_existing_setup_script(chroot_rule_runner) -> None:
@@ -1167,7 +1167,7 @@ def assert_owner_error(rule_runner, owned: Address, exc_cls: type[Exception]):
         )
     ex = excinfo.value
     assert len(ex.wrapped_exceptions) == 1
-    assert type(ex.wrapped_exceptions[0]) == exc_cls
+    assert type(ex.wrapped_exceptions[0]) is exc_cls
 
 
 def assert_no_owner(rule_runner: PythonRuleRunner, owned: Address):

src/python/pants/engine/collection.py

@@ -42,7 +42,7 @@ def __getitem__(self, index: int | slice) -> T | Collection[T]:  # noqa: F811
     def __eq__(self, other: Any) -> bool:
         if self is other:
             return True
-        return type(self) == type(other) and super().__eq__(other)
+        return type(self) is type(other) and super().__eq__(other)
 
     def __ne__(self, other: Any) -> bool:
         # We must explicitly override to provide the inverse of _our_ __eq__ and not get the

src/python/pants/option/ranked_value.py

@@ -29,7 +29,7 @@ def __new__(cls, rank: int, display: str) -> Rank:
         return member
 
     def __lt__(self, other: Any) -> bool:
-        if type(other) != Rank:
+        if type(other) != Rank:  # noqa: E721
             return NotImplemented
         return self._rank < other._rank
 

src/python/pants/option/subsystem.py

@@ -309,7 +309,7 @@ def __init__(self, options: OptionValueContainer) -> None:
         self.options = options
 
     def __eq__(self, other: Any) -> bool:
-        if type(self) != type(other):
+        if type(self) != type(other):  # noqa: E721
             return False
         return bool(self.options == other.options)
 

src/python/pants/util/memo_test.py

@@ -214,7 +214,7 @@ def __hash__(self):
             return hash(type)
 
         def __eq__(self, other):
-            return type(self) == type(other)
+            return type(self) == type(other)  # noqa: E721
 
     foo1 = Foo(3)
     foo2 = Foo(4)