fix: support empty tuple type

pydantic · Feb 4, 2021 · 42dd733 · 42dd733
1 parent 13a5c7d
commit 42dd733
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Showing 3 changed files with 15 additions and 5 deletions.
diff --git a/changes/2318-PrettyWood.md b/changes/2318-PrettyWood.md
@@ -0,0 +1 @@
+support empty tuple type
diff --git a/pydantic/fields.py b/pydantic/fields.py
@@ -449,18 +449,22 @@ def _type_analysis(self) -> None:  # noqa: C901 (ignore complexity)
 
         if issubclass(origin, Tuple):  # type: ignore
             # origin == Tuple without item type
-            if not get_args(self.type_):
+            args = get_args(self.type_)
+            if not args:
                 self.type_ = Any
                 self.shape = SHAPE_TUPLE_ELLIPSIS
             else:
                 self.shape = SHAPE_TUPLE
                 self.sub_fields = []
-                for i, t in enumerate(get_args(self.type_)):
+                for i, t in enumerate(args):
                     if t is Ellipsis:
                         self.type_ = get_args(self.type_)[0]
                         self.shape = SHAPE_TUPLE_ELLIPSIS
                         return
-                    self.sub_fields.append(self._create_sub_type(t, f'{self.name}_{i}'))
+                    elif t == ():
+                        self.type_ = Any
+                    else:
+                        self.sub_fields.append(self._create_sub_type(t, f'{self.name}_{i}'))
             return
 
         if issubclass(origin, List):

diff --git a/tests/test_edge_cases.py b/tests/test_edge_cases.py
@@ -194,11 +194,16 @@ class Model(BaseModel):
 
 def test_tuple_more():
     class Model(BaseModel):
+        empty_tuple: Tuple[()]
         simple_tuple: tuple = None
         tuple_of_different_types: Tuple[int, float, str, bool] = None
 
-    m = Model(simple_tuple=[1, 2, 3, 4], tuple_of_different_types=[4, 3, 2, 1])
-    assert m.dict() == {'simple_tuple': (1, 2, 3, 4), 'tuple_of_different_types': (4, 3.0, '2', True)}
+    m = Model(empty_tuple=[], simple_tuple=[1, 2, 3, 4], tuple_of_different_types=[4, 3, 2, 1])
+    assert m.dict() == {
+        'empty_tuple': (),
+        'simple_tuple': (1, 2, 3, 4),
+        'tuple_of_different_types': (4, 3.0, '2', True)
+    }
 
 
 def test_tuple_length_error():