Bandaid fix for strict parsing for some Sequences (#8614)

pydantic/_internal/_generate_schema.py

@@ -1388,8 +1388,9 @@ def _subclass_schema(self, type_: Any) -> core_schema.CoreSchema:
     def _sequence_schema(self, sequence_type: Any) -> core_schema.CoreSchema:
         """Generate schema for a Sequence, e.g. `Sequence[int]`."""
         item_type = self._get_first_arg_or_any(sequence_type)
+        item_type_schema = self.generate_schema(item_type)
+        list_schema = core_schema.list_schema(item_type_schema)
 
-        list_schema = core_schema.list_schema(self.generate_schema(item_type))
         python_schema = core_schema.is_instance_schema(typing.Sequence, cls_repr='Sequence')
         if item_type != Any:
             from ._validators import sequence_validator

pydantic/_internal/_validators.py

@@ -31,6 +31,14 @@ def sequence_validator(
             {'type_name': value_type.__name__},
         )
 
+    # TODO: refactor sequence validation to validate with either a list or a tuple
+    # schema, depending on the type of the value.
+    # Additionally, we should be able to remove one of either this validator or the
+    # SequenceValidator in _std_types_schema.py (preferably this one, while porting over some logic).
+    # Effectively, a refactor for sequence validation is needed.
+    if value_type == tuple:
+        __input_value = list(__input_value)
+
     v_list = validator(__input_value)
 
     # the rest of the logic is just re-creating the original type from `v_list`
@@ -39,6 +47,8 @@ def sequence_validator(
     elif issubclass(value_type, range):
         # return the list as we probably can't re-create the range
         return v_list
+    elif value_type == tuple:
+        return tuple(v_list)
     else:
         # best guess at how to re-create the original type, more custom construction logic might be required
         return value_type(v_list)  # type: ignore[call-arg]

tests/test_types.py

@@ -2389,6 +2389,10 @@ class Model(BaseModel):
     assert exc_info.value.errors(include_url=False) == errors
 
 
+def test_sequence_strict():
+    assert TypeAdapter(Sequence[int]).validate_python((), strict=True) == ()
+
+
 def test_int_validation():
     class Model(BaseModel):
         a: PositiveInt = None