cleanups, fix settings

mypy_django_plugin/plugins/settings.py

@@ -0,0 +1,61 @@
+from typing import cast, List
+
+from mypy.nodes import Var, Context, SymbolNode, SymbolTableNode
+from mypy.plugin import ClassDefContext
+from mypy.semanal import SemanticAnalyzerPass2
+from mypy.types import Instance, UnionType, NoneTyp, Type
+
+from mypy_django_plugin import helpers
+
+
+def get_error_context(node: SymbolNode) -> Context:
+    context = Context()
+    context.set_line(node)
+    return context
+
+
+def filter_out_nones(typ: UnionType) -> List[Type]:
+    return [item for item in typ.items if not isinstance(item, NoneTyp)]
+
+
+def copy_sym_of_instance(sym: SymbolTableNode) -> SymbolTableNode:
+    copied = sym.copy()
+    copied.node.info = sym.type.type
+    return copied
+
+
+def add_settings_to_django_conf_object(ctx: ClassDefContext,
+                                       settings_module: str) -> None:
+    api = cast(SemanticAnalyzerPass2, ctx.api)
+    if settings_module not in api.modules:
+        return None
+
+    settings_file = api.modules[settings_module]
+    for name, sym in settings_file.names.items():
+        if name.isupper() and isinstance(sym.node, Var):
+            if isinstance(sym.type, Instance):
+                copied = sym.copy()
+                copied.node.info = sym.type.type
+                ctx.cls.info.names[name] = copied
+
+            elif isinstance(sym.type, UnionType):
+                instances = filter_out_nones(sym.type)
+                if len(instances) > 1:
+                    # plain unions not supported yet
+                    continue
+                typ = instances[0]
+                if isinstance(typ, Instance):
+                    copied = sym.copy()
+                    copied.node.info = typ.type
+                    ctx.cls.info.names[name] = copied
+
+
+class DjangoConfSettingsInitializerHook(object):
+    def __init__(self, settings_module: str):
+        self.settings_module = settings_module
+
+    def __call__(self, ctx: ClassDefContext) -> None:
+        if not self.settings_module:
+            return
+
+        add_settings_to_django_conf_object(ctx, self.settings_module)