Fix typecheck

Author: m-novikov

mypy/build.py

@@ -625,7 +625,7 @@ def correct_rel_imp(imp: Union[ImportFrom, ImportAll]) -> str:
 
         return res
 
-    def find_module(self, id):
+    def find_module(self, id: str) -> Optional[str]:
         return self.module_discovery.find_module(id)
 
     def is_module(self, id: str) -> bool:
@@ -787,9 +787,9 @@ class ModuleType:
 
 
 class ImportContext:
-    def __init__(self):
+    def __init__(self) -> None:
         self.has_py = False  # type: bool
-        self.type = None  # type: int
+        self.type = None  # type: Optional[int]
         self.paths = []  # type: List[str]
 
     def maybe_add_path(self, path: str, type: int) -> None:
@@ -824,7 +824,7 @@ def _verify_module(self, path: str) -> bool:
 
     def _verify_namespace(self, path: str) -> bool:
         if os.path.isdir(path):
-            files = set(list_dir(path))
+            files = set(list_dir(path) or [])  # type: Set[str]
             if not ('__init__.py' in files or '__init__.pyi' in files):
                 return True
 
@@ -886,8 +886,8 @@ def _find_modules_recursive(self, module: str) -> List[BuildSource]:
 
         return srcs
 
-    def _find_submodules(self, module, path) -> Iterator[str]:
-        for item in list_dir(path):
+    def _find_submodules(self, module: str, path: str) -> Iterator[str]:
+        for item in list_dir(path) or []:
             if item == '__init__.py' or item == '__init__.pyi':
                 continue
 

mypy/stubgen.py

@@ -156,7 +156,8 @@ def find_module_path_and_all(module: str, pyversion: Tuple[int, int],
             module_all = getattr(mod, '__all__', None)
     else:
         # Find module by going through search path.
-        module_path = mypy.build.find_module(module, ['.'] + search_path)
+        md = mypy.build.ModuleDiscovery(['.'] + search_path)
+        module_path = md.find_module(module)
         if not module_path:
             raise SystemExit(
                 "Can't find module '{}' (consider using --search-path)".format(module))

mypy/test/testcheck.py

@@ -329,8 +329,8 @@ def parse_module(self,
             module_names = m.group(1)
             out = []
             for module_name in module_names.split(' '):
-                m = build.ModuleDiscovery([test_temp_dir], namespaces_allowed=False)
-                path = m.find_module(module_name)
+                md = build.ModuleDiscovery([test_temp_dir], namespaces_allowed=False)
+                path = md.find_module(module_name)
                 assert path is not None, "Can't find ad hoc case file"
                 with open(path) as f:
                     program_text = f.read()

mypy/test/testdmypy.py

@@ -270,8 +270,8 @@ def parse_module(self,
             module_names = m.group(1)
             out = []
             for module_name in module_names.split(' '):
-                m = build.ModuleDiscovery([test_temp_dir])
-                path = m.find_module(module_name)
+                md = build.ModuleDiscovery([test_temp_dir])
+                path = md.find_module(module_name)
                 assert path is not None, "Can't find ad hoc case file"
                 with open(path) as f:
                     program_text = f.read()

mypy/test/testmodulediscovery.py

@@ -1,20 +1,23 @@
-from mypy.build import ModuleDiscovery, find_module_clear_caches
+import os
+
 from unittest import mock, TestCase
+from typing import List, Set
+
+from mypy.build import ModuleDiscovery, find_module_clear_caches
 from mypy.myunit import Suite, assert_equal
-import os
 
 
 class ModuleDiscoveryTestCase(Suite):
-    def set_up(self):
-        self.files = {}
+    def set_up(self) -> None:
+        self.files = set()  # type: Set[str]
 
         self._setup_mock_filesystem()
 
-    def tear_down(self):
+    def tear_down(self) -> None:
         self._teardown_mock_filesystem()
         find_module_clear_caches()
 
-    def _list_dir(self, path: str) -> list:
+    def _list_dir(self, path: str) -> List:
         res = set()
 
         if not path.endswith(os.path.sep):