Fix StrictStr does not raise ValidationError when max_length is present in Field

changes/4388-hramezani.md

@@ -0,0 +1 @@
+Fix `StrictStr` does not raise `ValidationError` when `max_length` is present in `Field`

pydantic/schema.py

@@ -54,10 +54,10 @@
     ConstrainedInt,
     ConstrainedList,
     ConstrainedSet,
-    ConstrainedStr,
     SecretBytes,
     SecretStr,
     StrictBytes,
+    StrictStr,
     conbytes,
     condecimal,
     confloat,
@@ -1083,9 +1083,15 @@ def go(type_: Any) -> Type[Any]:
                 def constraint_func(**kw: Any) -> Type[Any]:
                     return type(type_.__name__, (type_,), kw)
 
-            elif issubclass(type_, str) and not issubclass(type_, (EmailStr, AnyUrl, ConstrainedStr)):
+            elif issubclass(type_, str) and not issubclass(type_, (EmailStr, AnyUrl)):
                 attrs = ('max_length', 'min_length', 'regex')
-                constraint_func = constr
+                if issubclass(type_, StrictStr):
+
+                    def constraint_func(**kw: Any) -> Type[Any]:
+                        return type(type_.__name__, (type_,), kw)
+
+                else:
+                    constraint_func = constr
             elif issubclass(type_, bytes):
                 attrs = ('max_length', 'min_length', 'regex')
                 if issubclass(type_, StrictBytes):

tests/test_types.py

@@ -1690,6 +1690,19 @@ class Model(BaseModel):
     assert m.v == 'foobar'
 
 
+def test_strict_str_max_length():
+    class Model(BaseModel):
+        u: StrictStr = Field(..., max_length=5)
+
+    assert Model(u='foo').u == 'foo'
+
+    with pytest.raises(ValidationError, match='str type expected'):
+        Model(u=123)
+
+    with pytest.raises(ValidationError, match='ensure this value has at most 5 characters'):
+        Model(u='1234567')
+
+
 def test_strict_bool():
     class Model(BaseModel):
         v: StrictBool