Enable strict optional for more test files (3) (#15597)

mypy/test/helpers.py

@@ -7,7 +7,7 @@
 import shutil
 import sys
 import time
-from typing import Any, Callable, Collection, Iterable, Iterator, Pattern
+from typing import Any, Callable, Iterable, Iterator, Pattern
 
 # Exporting Suite as alias to TestCase for backwards compatibility
 # TODO: avoid aliasing - import and subclass TestCase directly
@@ -317,10 +317,7 @@ def assert_type(typ: type, value: object) -> None:
 
 
 def parse_options(
-    program_text: str,
-    testcase: DataDrivenTestCase,
-    incremental_step: int,
-    no_strict_optional_files: Collection[str] = (),
+    program_text: str, testcase: DataDrivenTestCase, incremental_step: int
 ) -> Options:
     """Parse comments like '# flags: --foo' in a test case."""
     options = Options()
@@ -342,10 +339,6 @@ def parse_options(
     else:
         flag_list = []
         options = Options()
-        # TODO: Enable strict optional in test cases by default (requires *many* test case changes)
-        if os.path.basename(testcase.file) in no_strict_optional_files:
-            options.strict_optional = False
-
         options.error_summary = False
         options.hide_error_codes = True
         options.force_uppercase_builtins = True

mypy/test/testfinegrained.py

@@ -45,9 +45,6 @@
 # Set to True to perform (somewhat expensive) checks for duplicate AST nodes after merge
 CHECK_CONSISTENCY = False
 
-# TODO: Enable strict optional in test cases by default. Remove files here, once test cases are updated
-no_strict_optional_files = {"fine-grained.test", "fine-grained-suggest.test"}
-
 
 class FineGrainedSuite(DataSuite):
     files = find_test_files(
@@ -143,9 +140,7 @@ def run_case(self, testcase: DataDrivenTestCase) -> None:
 
     def get_options(self, source: str, testcase: DataDrivenTestCase, build_cache: bool) -> Options:
         # This handles things like '# flags: --foo'.
-        options = parse_options(
-            source, testcase, incremental_step=1, no_strict_optional_files=no_strict_optional_files
-        )
+        options = parse_options(source, testcase, incremental_step=1)
         options.incremental = True
         options.use_builtins_fixtures = True
         options.show_traceback = True

test-data/unit/fine-grained-suggest.test

@@ -1090,7 +1090,7 @@ optional2(10)
 optional2('test')
 
 def optional3(x: Optional[List[Any]]):
-    assert not x
+    assert x
     return x[0]
 
 optional3(test)

test-data/unit/fine-grained.test

@@ -191,7 +191,7 @@ main:3: error: "A" has no attribute "x"
 [case testVariableTypeBecomesInvalid]
 import m
 def f() -> None:
-    a = None # type: m.A
+    a: m.A
 [file m.py]
 class A: pass
 [file m.py.2]
@@ -1724,15 +1724,15 @@ f = 1
 main:1: error: Module "a" has no attribute "f"
 
 [case testDecoratedMethodRefresh]
-from typing import Iterator, Callable, List
+from typing import Iterator, Callable, List, Optional
 from a import f
 import a
 
-def dec(f: Callable[['A'], Iterator[int]]) -> Callable[[int], int]: pass
+def dec(f: Callable[['A'], Optional[Iterator[int]]]) -> Callable[[int], int]: pass
 
 class A:
     @dec
-    def f(self) -> Iterator[int]:
+    def f(self) -> Optional[Iterator[int]]:
         self.x = a.g()  # type: int
         return None
 [builtins fixtures/list.pyi]
@@ -4626,6 +4626,7 @@ class User:
 ==
 
 [case testNoStrictOptionalModule]
+# flags: --no-strict-optional
 import a
 a.y = a.x
 [file a.py]
@@ -4643,9 +4644,10 @@ y: int
 [out]
 ==
 ==
-main:2: error: Incompatible types in assignment (expression has type "Optional[str]", variable has type "int")
+main:3: error: Incompatible types in assignment (expression has type "Optional[str]", variable has type "int")
 
 [case testNoStrictOptionalFunction]
+# flags: --no-strict-optional
 import a
 from typing import Optional
 def f() -> None:
@@ -4666,9 +4668,10 @@ def g(x: str) -> None:
 [out]
 ==
 ==
-main:5: error: Argument 1 to "g" has incompatible type "Optional[int]"; expected "str"
+main:6: error: Argument 1 to "g" has incompatible type "Optional[int]"; expected "str"
 
 [case testNoStrictOptionalMethod]
+# flags: --no-strict-optional
 import a
 from typing import Optional
 class C:
@@ -4693,7 +4696,7 @@ class B:
 [out]
 ==
 ==
-main:6: error: Argument 1 to "g" of "B" has incompatible type "Optional[int]"; expected "str"
+main:7: error: Argument 1 to "g" of "B" has incompatible type "Optional[int]"; expected "str"
 
 [case testStrictOptionalModule]
 # flags: --strict-optional
@@ -5276,10 +5279,11 @@ class I(metaclass=ABCMeta):
     @abstractmethod
     def f(self) -> None: pass
 [file b.py]
+from typing import Optional
 from z import I
 class Foo(I):
     pass
-def x() -> Foo: return None
+def x() -> Optional[Foo]: return None
 [file z.py.2]
 from abc import abstractmethod, ABCMeta
 class I(metaclass=ABCMeta):
@@ -5301,10 +5305,11 @@ class I(metaclass=ABCMeta):
     @abstractmethod
     def f(self) -> None: pass
 [file b.py]
+from typing import Optional
 from a import I
 class Foo(I):
     pass
-def x() -> Foo: return None
+def x() -> Optional[Foo]: return None
 [file a.py.2]
 from abc import abstractmethod, ABCMeta
 class I(metaclass=ABCMeta):
@@ -7769,7 +7774,8 @@ from typing import List
 import b
 class A(b.B):
     def meth(self) -> None:
-        self.x, *self.y = None, None  # type: str, List[str]
+        self.x: str
+        self.y: List[str]
 [file b.py]
 from typing import List
 class B:
@@ -7781,7 +7787,7 @@ class B:
 [builtins fixtures/list.pyi]
 [out]
 ==
-main:5: error: Incompatible types in assignment (expression has type "List[str]", base class "B" defined the type as "List[int]")
+main:6: error: Incompatible types in assignment (expression has type "List[str]", base class "B" defined the type as "List[int]")
 
 [case testLiskovFineVariableCleanDefInMethodNested-only_when_nocache]
 from b import B
@@ -9109,27 +9115,27 @@ import a
 [file a.py]
 # mypy: no-warn-no-return
 
-from typing import List
-def foo() -> List:
+from typing import List, Optional
+def foo() -> Optional[List]:
     20
 
 [file a.py.2]
 # mypy: disallow-any-generics, no-warn-no-return
 
-from typing import List
-def foo() -> List:
+from typing import List, Optional
+def foo() -> Optional[List]:
     20
 
 [file a.py.3]
 # mypy: no-warn-no-return
 
-from typing import List
-def foo() -> List:
+from typing import List, Optional
+def foo() -> Optional[List]:
     20
 
 [file a.py.4]
-from typing import List
-def foo() -> List:
+from typing import List, Optional
+def foo() -> Optional[List]:
     20
 [out]
 ==
@@ -9867,7 +9873,7 @@ x = 0  # Arbitrary change to trigger reprocessing
 [builtins fixtures/dict.pyi]
 [out]
 ==
-a.py:5: note: Revealed type is "def (x: builtins.int) -> builtins.str"
+a.py:5: note: Revealed type is "def (x: builtins.int) -> Union[builtins.str, None]"
 
 [case testTypeVarTupleCached]
 import a