mypy: Iterator is better than Generator

Author: nedbat

coverage/bytecode.py

@@ -6,10 +6,10 @@
 from __future__ import annotations
 
 from types import CodeType
-from typing import Generator
+from typing import Iterator
 
 
-def code_objects(code: CodeType) -> Generator[CodeType, None, None]:
+def code_objects(code: CodeType) -> Iterator[CodeType]:
     """Iterate over all the code objects in `code`."""
     stack = [code]
     while stack:

coverage/control.py

@@ -20,7 +20,7 @@
 from types import FrameType
 from typing import (
     cast,
-    Any, Callable, Dict, Generator, IO, Iterable, List, Optional, Tuple, Union,
+    Any, Callable, Dict, IO, Iterable, Iterator, List, Optional, Tuple, Union,
 )
 
 from coverage import env
@@ -56,7 +56,7 @@
 os = isolate_module(os)
 
 @contextlib.contextmanager
-def override_config(cov: Coverage, **kwargs: TConfigValueIn) -> Generator[None, None, None]:
+def override_config(cov: Coverage, **kwargs: TConfigValueIn) -> Iterator[None]:
     """Temporarily tweak the configuration of `cov`.
 
     The arguments are applied to `cov.config` with the `from_args` method.

coverage/debug.py

@@ -18,8 +18,7 @@
 import _thread
 
 from typing import (
-    Any, Callable, Generator, IO, Iterable, Iterator, Optional, List, Tuple,
-    cast,
+    Any, Callable, IO, Iterable, Iterator, Optional, List, Tuple, cast,
 )
 
 from coverage.misc import isolate_module
@@ -65,7 +64,7 @@ def should(self, option: str) -> bool:
         return (option in self.options)
 
     @contextlib.contextmanager
-    def without_callers(self) -> Generator[None, None, None]:
+    def without_callers(self) -> Iterator[None]:
         """A context manager to prevent call stacks from being logged."""
         old = self.suppress_callers
         self.suppress_callers = True

coverage/misc.py

@@ -21,7 +21,7 @@
 
 from types import ModuleType
 from typing import (
-    Any, Callable, Dict, Generator, IO, Iterable, List, Mapping, Optional,
+    Any, Callable, Dict, IO, Iterable, Iterator, List, Mapping, Optional,
     Sequence, Tuple, TypeVar, Union,
 )
 
@@ -71,7 +71,7 @@ def restore(self) -> None:
 
 
 @contextlib.contextmanager
-def sys_modules_saved() -> Generator[None, None, None]:
+def sys_modules_saved() -> Iterator[None]:
     """A context manager to remove any modules imported during a block."""
     saver = SysModuleSaver()
     try:

coverage/sqldata.py

@@ -22,8 +22,8 @@
 import zlib
 
 from typing import (
-    cast, Any, Callable, Collection, Dict, Generator, Iterable, List, Mapping, Optional,
-    Sequence, Set, Tuple, TypeVar, Union,
+    cast, Any, Callable, Collection, Dict, Iterable, Iterator, List, Mapping,
+    Optional, Sequence, Set, Tuple, TypeVar, Union,
 )
 
 from coverage.debug import NoDebugging, AutoReprMixin, clipped_repr
@@ -1171,7 +1171,7 @@ def execute(
         self,
         sql: str,
         parameters: Iterable[Any]=(),
-    ) -> Generator[sqlite3.Cursor, None, None]:
+    ) -> Iterator[sqlite3.Cursor]:
         """Context managed :meth:`python:sqlite3.Connection.execute`.
 
         Use with a ``with`` statement to auto-close the returned cursor.

tests/conftest.py

@@ -15,7 +15,7 @@
 import warnings
 
 from pathlib import Path
-from typing import Generator, Optional
+from typing import Iterator, Optional
 
 import pytest
 
@@ -65,15 +65,15 @@ def set_warnings() -> None:
 
 
 @pytest.fixture(autouse=True)
-def reset_sys_path() -> Generator[None, None, None]:
+def reset_sys_path() -> Iterator[None]:
     """Clean up sys.path changes around every test."""
     sys_path = list(sys.path)
     yield
     sys.path[:] = sys_path
 
 
 @pytest.fixture(autouse=True)
-def reset_environment() -> Generator[None, None, None]:
+def reset_environment() -> Iterator[None]:
     """Make sure a test setting an envvar doesn't leak into another test."""
     old_environ = os.environ.copy()
     yield
@@ -82,7 +82,7 @@ def reset_environment() -> Generator[None, None, None]:
 
 
 @pytest.fixture(autouse=True)
-def reset_filesdotpy_globals() -> Generator[None, None, None]:
+def reset_filesdotpy_globals() -> Iterator[None]:
     """coverage/files.py has some unfortunate globals. Reset them every test."""
     set_relative_directory()
     yield
@@ -110,7 +110,7 @@ def pytest_sessionfinish() -> None:
                 pth_file.unlink()
 
 
-def possible_pth_dirs() -> Generator[Path, None, None]:
+def possible_pth_dirs() -> Iterator[Path]:
     """Produce a sequence of directories for trying to write .pth files."""
     # First look through sys.path, and if we find a .pth file, then it's a good
     # place to put ours.

tests/coveragetest.py

@@ -19,7 +19,7 @@
 
 from types import ModuleType
 from typing import (
-    Any, Collection, Dict, Generator, Iterable, List, Mapping, Optional,
+    Any, Collection, Dict, Iterable, Iterator, List, Mapping, Optional,
     Sequence, Tuple, Union,
 )
 
@@ -272,7 +272,7 @@ def assert_warnings(
         cov: Coverage,
         warnings: Iterable[str],
         not_warnings: Iterable[str]=(),
-    ) -> Generator[None, None, None]:
+    ) -> Iterator[None]:
         """A context manager to check that particular warnings happened in `cov`.
 
         `cov` is a Coverage instance.  `warnings` is a list of regexes.  Every

tests/helpers.py

@@ -16,8 +16,8 @@
 import warnings
 
 from typing import (
-    cast,
-    Any, Callable, Generator, Iterable, List, Optional, Set, Tuple, Type, TypeVar, Union,
+    Any, Callable, Iterable, Iterator, List, Optional, Set, Tuple, Type,
+    TypeVar, Union, cast,
 )
 
 import pytest
@@ -267,7 +267,7 @@ def arcs_to_arcz_repr(arcs: Optional[Iterable[TArc]]) -> str:
 
 
 @contextlib.contextmanager
-def change_dir(new_dir: str) -> Generator[None, None, None]:
+def change_dir(new_dir: str) -> Iterator[None]:
     """Change directory, and then change back.
 
     Use as a context manager, it will return to the original
@@ -322,7 +322,7 @@ def assert_coverage_warnings(
 def swallow_warnings(
     message: str=r".",
     category: Type[Warning]=CoverageWarning,
-) -> Generator[None, None, None]:
+) -> Iterator[None]:
     """Swallow particular warnings.
 
     It's OK if they happen, or if they don't happen. Just ignore them.

tests/test_execfile.py

@@ -14,7 +14,7 @@
 import re
 import sys
 
-from typing import Any, Generator
+from typing import Any, Iterator
 
 import pytest
 
@@ -31,7 +31,7 @@ class RunFileTest(CoverageTest):
     """Test cases for `run_python_file`."""
 
     @pytest.fixture(autouse=True)
-    def clean_up(self) -> Generator[None, None, None]:
+    def clean_up(self) -> Iterator[None]:
         """These tests all run in-process. Clean up global changes."""
         yield
         sys.excepthook = sys.__excepthook__

tests/test_files.py

@@ -10,7 +10,7 @@
 import os.path
 import re
 
-from typing import Any, Generator, Iterable, List
+from typing import Any, Iterable, Iterator, List
 from unittest import mock
 
 import pytest
@@ -137,7 +137,7 @@ def globs_to_regex_params(
     partial: bool=False,
     matches: Iterable[str]=(),
     nomatches: Iterable[str]=(),
-) -> Generator[Any, None, None]:
+) -> Iterator[Any]:
     """Generate parameters for `test_globs_to_regex`.
 
     `patterns`, `case_insensitive`, and `partial` are arguments for