Fix BaseConfig max_anystr_length default to fixed number to None (#350)

* Fix BaseConfig max_anystr_length default to fixed number to None

* Update History

HISTORY.rst

@@ -10,6 +10,8 @@ v0.18.0 (unreleased)
   ``whole`` validators being called for sub-fields, fix #132 by @samuelcolvin
 * improve documentation for settings priority and allow it to be easily changed, #343 by @samuelcolvin
 * fix ``ignore_extra=False`` and ``allow_population_by_alias=True``, fix #257 by @samuelcolvin
+* **breaking change**: Set ``BaseConfig`` attributes ``min_anystr_length`` and ``max_anystr_length`` to
+    ``None`` by default, fix #349 in #350, by @tiangolo
 
 v0.17.0 (2018-12-27)
 ....................

pydantic/main.py

@@ -22,8 +22,8 @@ from .validators import dict_validator
 class BaseConfig:
     title = None
     anystr_strip_whitespace = False
-    min_anystr_length = 0
-    max_anystr_length = 2 ** 16
+    min_anystr_length = None
+    max_anystr_length = None
     validate_all = False
     ignore_extra = True
     allow_extra = False

tests/test_construction.py

@@ -25,6 +25,18 @@ def test_construct_missing():
     assert "'Model' object has no attribute 'b'" in str(exc_info)
 
 
+def test_large_any_str():
+    class Model(BaseModel):
+        a: bytes
+        b: str
+
+    content_bytes = b"x" * (2 ** 16 + 1)
+    content_str = "x" * (2 ** 16 + 1)
+    m = Model(a=content_bytes, b=content_str)
+    assert m.a == content_bytes
+    assert m.b == content_str
+
+
 def test_simple_copy():
     m = Model(a=24)
     m2 = m.copy()