fix: support plain typing.Tuple (#2133)

closes #2132

changes/2132-PrettyWood.md

@@ -0,0 +1 @@
+Support plain `typing.Tuple` type

pydantic/fields.py

@@ -346,7 +346,6 @@ class ModelField(Representation):
         Note: this method is **not** idempotent (because _type_analysis is not idempotent),
         e.g. calling it it multiple times may modify the field and configure it incorrectly.
         """
-
         self._set_default_and_type()
         if self.type_.__class__ == ForwardRef:
             # self.type_ is currently a ForwardRef and there's nothing we can do now,
@@ -448,14 +447,19 @@ class ModelField(Representation):
             return
 
         if issubclass(origin, Tuple):  # type: ignore
-            self.shape = SHAPE_TUPLE
-            self.sub_fields = []
-            for i, t in enumerate(get_args(self.type_)):
-                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}'))
+            # origin == Tuple without item type
+            if not get_args(self.type_):
+                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_)):
+                    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}'))
             return
 
         if issubclass(origin, List):
@@ -605,6 +609,8 @@ class ModelField(Representation):
             e: errors_.PydanticTypeError
             if self.shape == SHAPE_LIST:
                 e = errors_.ListError()
+            elif self.shape in (SHAPE_TUPLE, SHAPE_TUPLE_ELLIPSIS):
+                e = errors_.TupleError()
             elif self.shape == SHAPE_SET:
                 e = errors_.SetError()
             elif self.shape == SHAPE_FROZENSET:

tests/test_types.py

@@ -2341,21 +2341,24 @@ def test_generic_without_params():
     class Model(BaseModel):
         generic_list: List
         generic_dict: Dict
+        generic_tuple: Tuple
 
-    m = Model(generic_list=[0, 'a'], generic_dict={0: 'a', 'a': 0})
-    assert m.dict() == {'generic_list': [0, 'a'], 'generic_dict': {0: 'a', 'a': 0}}
+    m = Model(generic_list=[0, 'a'], generic_dict={0: 'a', 'a': 0}, generic_tuple=(1, 'q'))
+    assert m.dict() == {'generic_list': [0, 'a'], 'generic_dict': {0: 'a', 'a': 0}, 'generic_tuple': (1, 'q')}
 
 
 def test_generic_without_params_error():
     class Model(BaseModel):
         generic_list: List
         generic_dict: Dict
+        generic_tuple: Tuple
 
     with pytest.raises(ValidationError) as exc_info:
-        Model(generic_list=0, generic_dict=0)
+        Model(generic_list=0, generic_dict=0, generic_tuple=0)
     assert exc_info.value.errors() == [
         {'loc': ('generic_list',), 'msg': 'value is not a valid list', 'type': 'type_error.list'},
         {'loc': ('generic_dict',), 'msg': 'value is not a valid dict', 'type': 'type_error.dict'},
+        {'loc': ('generic_tuple',), 'msg': 'value is not a valid tuple', 'type': 'type_error.tuple'},
     ]