From bbb91822c86a654445f83256614da60f70f87f27 Mon Sep 17 00:00:00 2001
From: PrettyWood <em.jolibois@gmail.com>
Date: Mon, 4 Jan 2021 18:57:03 +0100
Subject: [PATCH] fix: support custom root type with nested models in
 `parse_obj`

---
 pydantic/main.py   |  6 +++---
 tests/test_main.py | 54 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 3 deletions(-)

diff --git a/pydantic/main.py b/pydantic/main.py
index 786ee22969f..6312d5eb395 100644
--- a/pydantic/main.py
+++ b/pydantic/main.py
@@ -662,14 +662,14 @@ def __get_validators__(cls) -> 'CallableGenerator':
 
     @classmethod
     def validate(cls: Type['Model'], value: Any) -> 'Model':
-        if isinstance(value, dict):
+        if cls.__custom_root_type__:
+            return cls.parse_obj(value)
+        elif isinstance(value, dict):
             return cls(**value)
         elif isinstance(value, cls):
             return value.copy()
         elif cls.__config__.orm_mode:
             return cls.from_orm(value)
-        elif cls.__custom_root_type__:
-            return cls.parse_obj(value)
         else:
             try:
                 value_as_dict = dict(value)
diff --git a/tests/test_main.py b/tests/test_main.py
index e026f59d058..5f9d3e75d51 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -1120,6 +1120,60 @@ class MyModel(BaseModel):
     ]
 
 
+def test_parse_obj_nested_root():
+    class Pokemon(BaseModel):
+        name: str
+        level: int
+
+    class Pokemons(BaseModel):
+        __root__: List[Pokemon]
+
+    class Player(BaseModel):
+        rank: int
+        pokemons: Pokemons
+
+    class Players(BaseModel):
+        __root__: Dict[str, Player]
+
+    class Tournament(BaseModel):
+        players: Players
+        city: str
+
+    payload = {
+        'players': {
+            'Jane': {
+                'rank': 1,
+                'pokemons': [
+                    {
+                        'name': 'Pikachu',
+                        'level': 100,
+                    },
+                    {
+                        'name': 'Bulbasaur',
+                        'level': 13,
+                    },
+                ],
+            },
+            'Tarzan': {
+                'rank': 2,
+                'pokemons': [
+                    {
+                        'name': 'Jigglypuff',
+                        'level': 7,
+                    },
+                ],
+            },
+        },
+        'city': 'Qwerty',
+    }
+
+    tournament = Tournament.parse_obj(payload)
+    assert tournament.city == 'Qwerty'
+    assert len(tournament.players.__root__) == 2
+    assert len(tournament.players.__root__['Jane'].pokemons.__root__) == 2
+    assert tournament.players.__root__['Jane'].pokemons.__root__[0].name == 'Pikachu'
+
+
 def test_untouched_types():
     from pydantic import BaseModel