Type annotations for pip._internal.build_env

src/pip/_internal/build_env.py

@@ -1,10 +1,6 @@
 """Build Environment used for isolation during sdist building
 """
 
-# The following comment should be removed at some point in the future.
-# mypy: strict-optional=False
-# mypy: disallow-untyped-defs=False
-
 import logging
 import os
 import sys
@@ -22,7 +18,8 @@ from pip._internal.utils.temp_dir import TempDirectory, tempdir_kinds
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 
 if MYPY_CHECK_RUNNING:
-    from typing import Tuple, Set, Iterable, Optional, List
+    from types import TracebackType
+    from typing import Tuple, Set, Iterable, Optional, List, Type
     from pip._internal.index.package_finder import PackageFinder
 
 logger = logging.getLogger(__name__)
@@ -110,6 +107,7 @@ class BuildEnvironment(object):
             ).format(system_sites=system_sites, lib_dirs=self._lib_dirs))
 
     def __enter__(self):
+        # type: () -> None
         self._save_env = {
             name: os.environ.get(name, None)
             for name in ('PATH', 'PYTHONNOUSERSITE', 'PYTHONPATH')
@@ -128,7 +126,13 @@ class BuildEnvironment(object):
             'PYTHONPATH': os.pathsep.join(pythonpath),
         })
 
-    def __exit__(self, exc_type, exc_val, exc_tb):
+    def __exit__(
+        self,
+        exc_type,  # type: Optional[Type[BaseException]]
+        exc_val,  # type: Optional[BaseException]
+        exc_tb  # type: Optional[TracebackType]
+    ):
+        # type: (...) -> None
         for varname, old_value in self._save_env.items():
             if old_value is None:
                 os.environ.pop(varname, None)
@@ -195,6 +199,7 @@ class BuildEnvironment(object):
             args.append('--pre')
         args.append('--')
         args.extend(requirements)
+        assert message
         with open_spinner(message) as spinner:
             call_subprocess(args, spinner=spinner)
 
@@ -204,16 +209,32 @@ class NoOpBuildEnvironment(BuildEnvironment):
     """
 
     def __init__(self):
+        # type: () -> None
         pass
 
     def __enter__(self):
+        # type: () -> None
         pass
 
-    def __exit__(self, exc_type, exc_val, exc_tb):
+    def __exit__(
+        self,
+        exc_type,  # type: Optional[Type[BaseException]]
+        exc_val,  # type: Optional[BaseException]
+        exc_tb  # type: Optional[TracebackType]
+    ):
+        # type: (...) -> None
         pass
 
     def cleanup(self):
+        # type: () -> None
         pass
 
-    def install_requirements(self, finder, requirements, prefix, message):
+    def install_requirements(
+        self,
+        finder,  # type: PackageFinder
+        requirements,  # type: Iterable[str]
+        prefix_as_string,  # type: str
+        message  # type: Optional[str]
+    ):
+        # type: (...) -> None
         raise NotImplementedError()