Merge pull request #193 from jacebrowning/test-python-3.9

Test against Python 3.9

.appveyor.yml

@@ -4,6 +4,9 @@ environment:
       PYTHON_MINOR: 7
     - PYTHON_MAJOR: 3
       PYTHON_MINOR: 8
+    # TODO: Enable this when Python 3.9 is available in the default images
+    # - PYTHON_MAJOR: 3
+    #   PYTHON_MINOR: 9
 
 cache:
   - .venv -> poetry.lock

.pylint.ini

@@ -35,6 +35,7 @@ disable=
     unsupported-membership-test,
     cell-var-from-loop,
     cyclic-import,
+    comparison-with-callable,
 
 init-import=yes
 

.python-version

@@ -1 +1 @@
-3.8.2
+3.9.0

.travis.yml

@@ -4,6 +4,7 @@ language: python
 python:
   - 3.7
   - 3.8
+  - 3.9
 
 cache:
   pip: true

CHANGELOG.md

@@ -1,6 +1,7 @@
 # 0.12 (beta)
 
 - Added `_exclude` parameter to `all()` and `filter()` manager methods to exclude certain objects from loading as a performance optimization.
+- Fixed handling of untyped `List`/`Dict` annotations in Python 3.9.
 
 # 0.11.1 (2020-09-12)
 

datafiles/converters/__init__.py

@@ -47,7 +47,7 @@ def map_type(cls, *, name: str = '', item_cls: Optional[type] = None):
     if dataclasses.is_dataclass(cls):
         converters = {}
         for field in dataclasses.fields(cls):
-            converters[field.name] = map_type(field.type, name=field.name)
+            converters[field.name] = map_type(field.type, name=field.name)  # type: ignore
         converter = Dataclass.of_mappings(cls, converters)
         log.debug(f'Mapped {cls!r} to new converter: {converter}')
         return converter
@@ -58,9 +58,12 @@ def map_type(cls, *, name: str = '', item_cls: Optional[type] = None):
         if cls.__origin__ == list:
             try:
                 converter = map_type(item_cls or cls.__args__[0])
-            except TypeError as e:
+            except TypeError as e:  # Python 3.8 behavior
                 assert '~T' in str(e), f'Unhandled error: {e}'
                 raise TypeError("Type is required with 'List' annotation") from None
+            except AttributeError as e:  # Python 3.9 behavior
+                assert '__args__' in str(e), f'Unhandled error: {e}'
+                raise TypeError("Type is required with 'List' annotation") from None
             else:
                 converter = List.of_type(converter)
 
@@ -73,11 +76,16 @@ def map_type(cls, *, name: str = '', item_cls: Optional[type] = None):
                 try:
                     key = map_type(cls.__args__[0])
                     value = map_type(cls.__args__[1])
-                except TypeError as e:
+                except TypeError as e:  # Python 3.8 behavior
                     assert '~' in str(e), f'Unhandled error: {e}'
                     raise TypeError(
                         "Types are required with 'Dict' annotation"
                     ) from None
+                except AttributeError as e:  # Python 3.9 behavior
+                    assert '__args__' in str(e), f'Unhandled error: {e}'
+                    raise TypeError(
+                        "Types are required with 'Dict' annotation"
+                    ) from None
 
             converter = Dictionary.of_mapping(key, value)
 

datafiles/mapper.py

@@ -212,7 +212,7 @@ def _infer_attr(name, value):
                 log.warn(f'{name!r} list type cannot be inferred')
                 item_cls = Converter
             log.debug(f'Inferring {name!r} type: {cls} of {item_cls}')
-            return map_type(cls, name=name, item_cls=item_cls)
+            return map_type(cls, name=name, item_cls=item_cls)  # type: ignore
 
         if issubclass(cls, dict):
             cls.__origin__ = dict
@@ -290,7 +290,7 @@ def create_mapper(obj, root=None) -> Mapper:
         for field in dataclasses.fields(obj):
             self_name = f'self.{field.name}'
             if pattern is None or self_name not in pattern:
-                attrs[field.name] = map_type(field.type, name=field.name)
+                attrs[field.name] = map_type(field.type, name=field.name)  # type: ignore
 
     return Mapper(
         obj,

pyproject.toml

@@ -1,7 +1,7 @@
 [tool.poetry]
 
 name = "datafiles"
-version = "0.12b1"
+version = "0.12b2"
 description = "File-based ORM for dataclasses."
 
 license = "MIT"
@@ -32,6 +32,7 @@ classifiers = [
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python",
     "Topic :: Software Development",
     "Topic :: Utilities",
@@ -64,8 +65,8 @@ black = "=20.8b1"
 isort = "=5.5.1"
 
 # Linters
-mypy = "*"
-pylint = '~2.6'
+mypy = "~0.790"
+pylint = { git = "https://github.com/PyCQA/pylint", branch = "master" }
 pydocstyle = "*"
 
 # Testing