Make sure to check the module cache before loading a module (again)

This hopefully results in some performance improvements (maybe numpy?).

jedi/inference/gradual/typeshed.py

@@ -91,9 +91,8 @@ def _cache_stub_file_map(version_info):
 def import_module_decorator(func):
     @wraps(func)
     def wrapper(inference_state, import_names, parent_module_value, sys_path, prefer_stubs):
-        try:
-            python_value_set = inference_state.module_cache.get(import_names)
-        except KeyError:
+        python_value_set = inference_state.module_cache.get(import_names)
+        if python_value_set is None:
             if parent_module_value is not None and parent_module_value.is_stub():
                 parent_module_values = parent_module_value.non_stub_value_set
             else:

jedi/inference/imports.py

@@ -38,18 +38,14 @@
 
 class ModuleCache(object):
     def __init__(self):
-        self._path_cache = {}
         self._name_cache = {}
 
     def add(self, string_names, value_set):
         if string_names is not None:
             self._name_cache[string_names] = value_set
 
     def get(self, string_names):
-        return self._name_cache[string_names]
-
-    def get_from_path(self, path):
-        return self._path_cache[path]
+        return self._name_cache.get(string_names)
 
 
 # This memoization is needed, because otherwise we will infinitely loop on
@@ -286,6 +282,14 @@ def follow(self):
         if not self.import_path or not self._infer_possible:
             return NO_VALUES
 
+        # Check caches first
+        from_cache = self._inference_state.stub_module_cache.get(self._str_import_path)
+        if from_cache is not None:
+            return ValueSet({from_cache})
+        from_cache = self._inference_state.module_cache.get(self._str_import_path)
+        if from_cache is not None:
+            return from_cache
+
         sys_path = self._sys_path_with_modifications(is_completion=False)
 
         return import_module_by_names(
@@ -455,7 +459,7 @@ def import_module(inference_state, import_names, parent_module_value, sys_path):
             return NO_VALUES
     else:
         module = _load_python_module(
-            inference_state, file_io_or_ns, sys_path,
+            inference_state, file_io_or_ns,
             import_names=import_names,
             is_package=is_pkg,
         )
@@ -467,13 +471,8 @@ def import_module(inference_state, import_names, parent_module_value, sys_path):
     return ValueSet([module])
 
 
-def _load_python_module(inference_state, file_io, sys_path=None,
+def _load_python_module(inference_state, file_io,
                         import_names=None, is_package=False):
-    try:
-        return inference_state.module_cache.get_from_path(file_io.path)
-    except KeyError:
-        pass
-
     module_node = inference_state.parse(
         file_io=file_io,
         cache=True,
@@ -511,7 +510,6 @@ def load_module_from_path(inference_state, file_io, base_names=None):
     here to ensure that a random path is still properly loaded into the Jedi
     module structure.
     """
-    e_sys_path = inference_state.get_sys_path()
     path = file_io.path
     if base_names:
         module_name = os.path.basename(path)
@@ -522,11 +520,11 @@ def load_module_from_path(inference_state, file_io, base_names=None):
         else:
             import_names = base_names + (module_name,)
     else:
+        e_sys_path = inference_state.get_sys_path()
         import_names, is_package = sys_path.transform_path_to_dotted(e_sys_path, path)
 
     module = _load_python_module(
         inference_state, file_io,
-        sys_path=e_sys_path,
         import_names=import_names,
         is_package=is_package,
     )

test/static_analysis/imports.py

@@ -18,7 +18,7 @@
 from datetime.date import today
 
 #! 16 import-error
-import datetime.date
+import datetime.datetime
 #! 7 import-error
 import not_existing_nested.date
 

test/static_analysis/try_except.py

@@ -17,7 +17,7 @@
     pass
 try:
     #! 7 import-error
-    import not_existing_import
+    import not_existing_import2
 except AttributeError:
     pass