incremental improvements to ming's type hinting (while avoiding circu…

…lar imports)

ming/odm/mapper.py

@@ -1,12 +1,18 @@
+from __future__ import annotations
+
+import typing
 import warnings
 from copy import copy
 
 from ming.base import Object, NoDefault
 from ming.utils import wordwrap
 
-from .base import ObjectState, state, _with_hooks
+from .base import ObjectState, ObjectState, state, _with_hooks
 from .property import FieldProperty
 
+if typing.TYPE_CHECKING:
+    # from ming.odm import ODMSession
+    from . import ODMSession, MappedClass
 
 def mapper(cls, collection=None, session=None, **kwargs):
     """Gets or creates the mapper for the given ``cls`` :class:`.MappedClass`"""
@@ -75,14 +81,14 @@ def __repr__(self):
             self.mapped_class.__name__, self.collection.m.collection_name)
 
     @_with_hooks('insert')
-    def insert(self, obj, state, session, **kwargs):
+    def insert(self, obj: MappedClass, state: ObjectState, session: ODMSession, **kwargs):
         doc = self.collection(state.document, skip_from_bson=True)
         ret = session.impl.insert(doc, validate=False)
         state.status = state.clean
         return ret
 
     @_with_hooks('update')
-    def update(self, obj, state, session, **kwargs):
+    def update(self, obj: MappedClass, state: ObjectState, session: ODMSession, **kwargs):
         fields = state.options.get('fields', None)
         if fields is None:
             fields = ()
@@ -93,12 +99,12 @@ def update(self, obj, state, session, **kwargs):
         return ret
 
     @_with_hooks('delete')
-    def delete(self, obj, state, session, **kwargs):
+    def delete(self, obj: MappedClass, state: ObjectState, session: ODMSession, **kwargs):
         doc = self.collection(state.document, skip_from_bson=True)
         return session.impl.delete(doc)
 
     @_with_hooks('remove')
-    def remove(self, session, *args, **kwargs):
+    def remove(self, session: ODMSession, *args, **kwargs):
         return session.impl.remove(self.collection, *args, **kwargs)
 
     def create(self, doc, options, remake=True):
@@ -176,7 +182,7 @@ def compile(self):
         for p in self.properties:
             p.compile(self)
 
-    def update_partial(self, session, *args, **kwargs):
+    def update_partial(self, session: ODMSession, *args, **kwargs):
         return session.impl.update_partial(self.collection, *args, **kwargs)
 
     def _from_doc(self, doc, options, validate=True):

ming/session.py

@@ -5,7 +5,8 @@
 
 import pymongo
 import pymongo.errors
-from pymongo.database import Database
+import pymongo.collection
+import pymongo.database
 
 from .base import Cursor, Object
 from .datastore import DataStore
@@ -48,14 +49,14 @@ def by_name(cls, name):
             result = cls._registry[name] = cls(cls._datastores.get(name))
         return result
 
-    def _impl(self, cls):
+    def _impl(self, cls) -> pymongo.collection.Collection:
         try:
             return self.db[cls.m.collection_name]
         except TypeError:
             raise exc.MongoGone('MongoDB is not connected')
 
     @property
-    def db(self) -> Database:
+    def db(self) -> pymongo.database.Database:
         if not self.bind:
             raise exc.MongoGone('No MongoDB connection for "%s"' % getattr(self, '_name', 'unknown connection'))
         return self.bind.db
@@ -146,7 +147,7 @@ def _prep_save(self, doc, validate):
         return data
 
     @annotate_doc_failure
-    def save(self, doc, *args, **kwargs):
+    def save(self, doc, *args, **kwargs) -> bson.ObjectId:
         data = self._prep_save(doc, kwargs.pop('validate', True))
         if args:
             data = {arg: data[arg] for arg in args}