PYTHON-4915 - Add guidance on adding _id fields to documents to CRUD spec

Author: NoahStapp

pymongo/asynchronous/bulk.py

@@ -133,7 +133,9 @@ def add_insert(self, document: _DocumentOut) -> None:
         validate_is_document_type("document", document)
         # Generate ObjectId client side.
         if not (isinstance(document, RawBSONDocument) or "_id" in document):
-            document["_id"] = ObjectId()
+            new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+            document.clear()
+            document.update(new_document)
         self.ops.append((_INSERT, document))
 
     def add_update(

pymongo/asynchronous/client_bulk.py

@@ -133,7 +133,9 @@ def add_insert(self, namespace: str, document: _DocumentOut) -> None:
         validate_is_document_type("document", document)
         # Generate ObjectId client side.
         if not (isinstance(document, RawBSONDocument) or "_id" in document):
-            document["_id"] = ObjectId()
+            new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+            document.clear()
+            document.update(new_document)
         cmd = {"insert": -1, "document": document}
         self.ops.append(("insert", cmd))
         self.namespaces.append(namespace)

pymongo/asynchronous/collection.py

@@ -885,7 +885,9 @@ async def insert_one(
         """
         common.validate_is_document_type("document", document)
         if not (isinstance(document, RawBSONDocument) or "_id" in document):
-            document["_id"] = ObjectId()  # type: ignore[index]
+            new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+            document.clear()
+            document.update(new_document)
 
         write_concern = self._write_concern_for(session)
         return InsertOneResult(
@@ -966,7 +968,9 @@ def gen() -> Iterator[tuple[int, Mapping[str, Any]]]:
                 common.validate_is_document_type("document", document)
                 if not isinstance(document, RawBSONDocument):
                     if "_id" not in document:
-                        document["_id"] = ObjectId()  # type: ignore[index]
+                        new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+                        document.clear()
+                        document.update(new_document)
                     inserted_ids.append(document["_id"])
                 yield (message._INSERT, document)
 

pymongo/synchronous/bulk.py

@@ -133,7 +133,9 @@ def add_insert(self, document: _DocumentOut) -> None:
         validate_is_document_type("document", document)
         # Generate ObjectId client side.
         if not (isinstance(document, RawBSONDocument) or "_id" in document):
-            document["_id"] = ObjectId()
+            new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+            document.clear()
+            document.update(new_document)
         self.ops.append((_INSERT, document))
 
     def add_update(

pymongo/synchronous/client_bulk.py

@@ -133,7 +133,9 @@ def add_insert(self, namespace: str, document: _DocumentOut) -> None:
         validate_is_document_type("document", document)
         # Generate ObjectId client side.
         if not (isinstance(document, RawBSONDocument) or "_id" in document):
-            document["_id"] = ObjectId()
+            new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+            document.clear()
+            document.update(new_document)
         cmd = {"insert": -1, "document": document}
         self.ops.append(("insert", cmd))
         self.namespaces.append(namespace)

pymongo/synchronous/collection.py

@@ -884,7 +884,9 @@ def insert_one(
         """
         common.validate_is_document_type("document", document)
         if not (isinstance(document, RawBSONDocument) or "_id" in document):
-            document["_id"] = ObjectId()  # type: ignore[index]
+            new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+            document.clear()
+            document.update(new_document)
 
         write_concern = self._write_concern_for(session)
         return InsertOneResult(
@@ -965,7 +967,9 @@ def gen() -> Iterator[tuple[int, Mapping[str, Any]]]:
                 common.validate_is_document_type("document", document)
                 if not isinstance(document, RawBSONDocument):
                     if "_id" not in document:
-                        document["_id"] = ObjectId()  # type: ignore[index]
+                        new_document = {"_id": ObjectId()} | document  # type: ignore[index]
+                        document.clear()
+                        document.update(new_document)
                     inserted_ids.append(document["_id"])
                 yield (message._INSERT, document)
 

test/asynchronous/test_collection.py

@@ -2277,6 +2277,14 @@ async def afind(*args, **kwargs):
         for helper, args in helpers:
             await helper(*args, let={})  # type: ignore
 
+    async def test_generated_id_order(self):
+        listener = OvertCommandListener()
+        c = await self.async_single_client(event_listeners=[listener])
+        listener.reset()
+
+        await c.db.test.insert_one({"x": 1})
+        self.assertEqual("_id", next(iter(listener.started_events[0].command["documents"][0])))
+
 
 if __name__ == "__main__":
     unittest.main()

test/test_collection.py

@@ -2254,6 +2254,14 @@ def afind(*args, **kwargs):
         for helper, args in helpers:
             helper(*args, let={})  # type: ignore
 
+    def test_generated_id_order(self):
+        listener = OvertCommandListener()
+        c = self.single_client(event_listeners=[listener])
+        listener.reset()
+
+        c.db.test.insert_one({"x": 1})
+        self.assertEqual("_id", next(iter(listener.started_events[0].command["documents"][0])))
+
 
 if __name__ == "__main__":
     unittest.main()