Merge branch 'master' into issue843

ChangeLog

@@ -57,6 +57,7 @@ Release Date: TBA
 
   Fixes #843
 
+* Reduce memory usage of astroid's module cache.
 
 What's New in astroid 2.4.3?
 ============================

astroid/interpreter/_import/spec.py

@@ -240,7 +240,7 @@ def _is_setuptools_namespace(location):
         with open(os.path.join(location, "__init__.py"), "rb") as stream:
             data = stream.read(4096)
     except IOError:
-        pass
+        return None
     else:
         extend_path = b"pkgutil" in data and b"extend_path" in data
         declare_namespace = (

astroid/manager.py

@@ -236,11 +236,13 @@ def file_from_module_name(self, modname, contextfile):
                 value = exceptions.AstroidImportError(
                     "Failed to import module {modname} with error:\n{error}.",
                     modname=modname,
-                    error=ex,
+                    # we remove the traceback here to save on memory usage (since these exceptions are cached)
+                    error=ex.with_traceback(None),
                 )
             self._mod_file_cache[(modname, contextfile)] = value
         if isinstance(value, exceptions.AstroidBuildingError):
-            raise value
+            # we remove the traceback here to save on memory usage (since these exceptions are cached)
+            raise value.with_traceback(None)
         return value
 
     def ast_from_module(self, module, modname=None):

astroid/node_classes.py

@@ -968,7 +968,7 @@ def next_sibling(self):
         try:
             return stmts[index + 1]
         except IndexError:
-            pass
+            return None
 
     def previous_sibling(self):
         """The previous sibling statement.