fix ci (lovasoa#185)

* Update dev dependencies
* mypy has gotten smarter, and it tries to do an automatic cast that breaks our code

* drop support for pre-commit hooks on 3.6

* downgrade types-dataclass

Author: lovasoa

.github/workflows/python-package.yml

@@ -31,7 +31,7 @@ jobs:
         python -m pip install --upgrade pip
         pip install --pre -e '.[dev]'
     - name: Pre-commit hooks
-      if: ${{ matrix.python_version != 'pypy3' }}
+      if: ${{ matrix.python_version != 'pypy3' && matrix.python_version != '3.6' }}
       run: pre-commit run --all-files
     - name: Test with pytest
       run: pytest

.pre-commit-config.yaml

@@ -1,27 +1,27 @@
 repos:
 - repo: https://github.com/asottile/pyupgrade
-  rev: v2.7.4
+  rev: v2.31.0 # Later versions do not support python 3.6
   hooks:
   - id: pyupgrade
     args: ["--py36-plus"]
 - repo: https://github.com/python/black
-  rev: 20.8b1
+  rev: 22.3.0
   hooks:
   - id: black
     language_version: python3
 - repo: https://gitlab.com/pycqa/flake8
-  rev: 3.8.4
+  rev: 3.9.2
   hooks:
   - id: flake8
     additional_dependencies: ['flake8-bugbear==19.8.0']
 - repo: https://github.com/pre-commit/mirrors-mypy
-  rev: v0.790
+  rev: v0.931 # Later versions do not support python 3.6
   hooks:
   - id: mypy
     additional_dependencies: [marshmallow-enum,typeguard,marshmallow]
     args: [--show-error-codes]
 - repo: https://github.com/asottile/blacken-docs
-  rev: v1.9.1
+  rev: v1.12.0 # Later versions do not support python 3.6
   hooks:
   - id: blacken-docs
     additional_dependencies: [black==19.3b0]

marshmallow_dataclass/__init__.py

@@ -597,8 +597,8 @@ def field_for_schema(
 
     # typing.NewType returns a function (in python <= 3.9) or a class (python >= 3.10) with a
     # __supertype__ attribute
-    if typing_inspect.is_new_type(typ):
-        newtype_supertype = getattr(typ, "__supertype__", None)
+    newtype_supertype = getattr(typ, "__supertype__", None)
+    if typing_inspect.is_new_type(typ) and newtype_supertype is not None:
         return _field_by_supertype(
             typ=typ,
             default=default,

setup.py

@@ -18,8 +18,8 @@
 EXTRAS_REQUIRE = {
     "enum": ["marshmallow-enum"],
     "union": ["typeguard"],
+    "lint": ["pre-commit~=2.17"],
     ':python_version == "3.6"': ["dataclasses", "types-dataclasses<0.6.4"],
-    "lint": ["pre-commit~=1.18"],
     "docs": ["sphinx"],
     "tests": [
         "pytest>=5.4",