mypy: check multiproc.py

2 files changed, 12 insertions, 11 deletions

diff --git a/coverage/multiproc.py b/coverage/multiproc.py
index 3a9bd633..e11ca7b7 100644
--- a/coverage/multiproc.py
+++ b/coverage/multiproc.py
@@ -10,7 +10,8 @@ import os.path
 import sys
 import traceback
 
-from coverage.misc import contract
+from typing import Any, Dict
+
 
 # An attribute that will be set on the module to indicate that it has been
 # monkey-patched.
@@ -18,12 +19,12 @@ PATCHED_MARKER = "_coverage$patched"
 
 
 OriginalProcess = multiprocessing.process.BaseProcess
-original_bootstrap = OriginalProcess._bootstrap
+original_bootstrap = OriginalProcess._bootstrap     # type: ignore[attr-defined]
 
 class ProcessWithCoverage(OriginalProcess):         # pylint: disable=abstract-method
     """A replacement for multiprocess.Process that starts coverage."""
 
-    def _bootstrap(self, *args, **kwargs):
+    def _bootstrap(self, *args, **kwargs):          # type: ignore[no-untyped-def]
         """Wrapper around _bootstrap to start coverage."""
         try:
             from coverage import Coverage       # avoid circular import
@@ -31,6 +32,7 @@ class ProcessWithCoverage(OriginalProcess):         # pylint: disable=abstract-m
             cov._warn_preimported_source = False
             cov.start()
             debug = cov._debug
+            assert debug is not None
             if debug.should("multiproc"):
                 debug.write("Calling multiprocessing bootstrap")
         except Exception:
@@ -50,18 +52,17 @@ class ProcessWithCoverage(OriginalProcess):         # pylint: disable=abstract-m
 
 class Stowaway:
     """An object to pickle, so when it is unpickled, it can apply the monkey-patch."""
-    def __init__(self, rcfile):
+    def __init__(self, rcfile: str) -> None:
         self.rcfile = rcfile
 
-    def __getstate__(self):
+    def __getstate__(self) -> Dict[str, str]:
         return {'rcfile': self.rcfile}
 
-    def __setstate__(self, state):
+    def __setstate__(self, state: Dict[str, str]) -> None:
         patch_multiprocessing(state['rcfile'])
 
 
-@contract(rcfile=str)
-def patch_multiprocessing(rcfile):
+def patch_multiprocessing(rcfile: str) -> None:
     """Monkey-patch the multiprocessing module.
 
     This enables coverage measurement of processes started by multiprocessing.
@@ -74,7 +75,7 @@ def patch_multiprocessing(rcfile):
     if hasattr(multiprocessing, PATCHED_MARKER):
         return
 
-    OriginalProcess._bootstrap = ProcessWithCoverage._bootstrap
+    OriginalProcess._bootstrap = ProcessWithCoverage._bootstrap     # type: ignore[attr-defined]
 
     # Set the value in ProcessWithCoverage that will be pickled into the child
     # process.
@@ -92,7 +93,7 @@ def patch_multiprocessing(rcfile):
     except (ImportError, AttributeError):
         pass
     else:
-        def get_preparation_data_with_stowaway(name):
+        def get_preparation_data_with_stowaway(name: str) -> Dict[str, Any]:
             """Get the original preparation data, and also insert our stowaway."""
             d = original_get_preparation_data(name)
             d['stowaway'] = Stowaway(rcfile)
diff --git a/tox.ini b/tox.ini
index e1785719..4b641842 100644
--- a/tox.ini
+++ b/tox.ini
@@ -97,7 +97,7 @@ deps =
 
 setenv =
     {[testenv]setenv}
-    T_AN=coverage/config.py coverage/files.py coverage/numbits.py
+    T_AN=coverage/config.py coverage/files.py coverage/multiproc.py coverage/numbits.py
     T_OP=coverage/parser.py coverage/phystokens.py coverage/plugin.py coverage/python.py
     T_QZ=coverage/results.py coverage/sqldata.py coverage/tomlconfig.py coverage/types.py
     TYPEABLE={env:T_AN} {env:T_OP} {env:T_QZ}