drop python3.6 support (pydantic#3605)

* drop python3.6 support

* revert small change

* fix 3.7 failures

* more cases and cleanup

* add change description

Author: samuelcolvin

.github/workflows/ci.yml

@@ -65,7 +65,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10']
+        python-version: ['3.7', '3.8', '3.9', '3.10']
     env:
       PYTHON: ${{ matrix.python-version }}
       OS: ubuntu
@@ -131,7 +131,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [macos, windows]
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10']
+        python-version: ['3.7', '3.8', '3.9', '3.10']
     env:
       PYTHON: ${{ matrix.python-version }}
       OS: ${{ matrix.os }}
@@ -283,7 +283,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu , macos , windows]
-        python-version: ['6', '7', '8', '9', '10']
+        python-version: ['7', '8', '9', '10']
         include:
         - os: ubuntu
           platform: linux

README.md

@@ -8,10 +8,10 @@
 [![versions](https://img.shields.io/pypi/pyversions/pydantic.svg)](https://github.com/samuelcolvin/pydantic)
 [![license](https://img.shields.io/github/license/samuelcolvin/pydantic.svg)](https://github.com/samuelcolvin/pydantic/blob/master/LICENSE)
 
-Data validation and settings management using Python type hinting.
+Data validation and settings management using Python type hints.
 
 Fast and extensible, *pydantic* plays nicely with your linters/IDE/brain.
-Define how data should be in pure, canonical Python 3.6+; validate it with *pydantic*.
+Define how data should be in pure, canonical Python 3.7+; validate it with *pydantic*.
 
 ## Help
 

changes/3605-samuelcolvin.md

@@ -0,0 +1 @@
+Drop support for python3.6, associated cleanup

docs/contributing.md

@@ -33,7 +33,7 @@ To make contributing as easy and fast as possible, you'll want to run tests and
 *pydantic* has few dependencies, doesn't require compiling and tests don't need access to databases, etc.
 Because of this, setting up and running the tests should be very simple.
 
-You'll need to have a version between **python 3.6 and 3.10**, **virtualenv**, **git**, and **make** installed.
+You'll need to have a version between **python 3.7 and 3.10**, **virtualenv**, **git**, and **make** installed.
 
 ```bash
 # 1. clone your fork and cd into the repo directory
@@ -44,7 +44,7 @@ cd pydantic
 virtualenv -p `which python3.8` env
 source env/bin/activate
 # Building docs requires 3.8. If you don't need to build docs you can use
-# whichever version; 3.6 will work too.
+# whichever version; 3.7 will work too.
 
 # 3. Install pydantic, dependencies, test dependencies and doc dependencies
 make install

docs/install.md

@@ -4,10 +4,9 @@ Installation is as simple as:
 pip install pydantic
 ```
 
-*pydantic* has no required dependencies except python 3.6, 3.7, 3.8, 3.9 or 3.10,
-[`typing-extensions`](https://pypi.org/project/typing-extensions/), and the
-[`dataclasses`](https://pypi.org/project/dataclasses/) backport package for python 3.6.
-If you've got python 3.6+ and `pip` installed, you're good to go.
+*pydantic* has no required dependencies except python 3.7, 3.8, 3.9 or 3.10 and
+[`typing-extensions`](https://pypi.org/project/typing-extensions/).
+If you've got python 3.7+ and `pip` installed, you're good to go.
 
 Pydantic is also available on [conda](https://www.anaconda.com) under the [conda-forge](https://conda-forge.org)
 channel:

docs/usage/dataclasses.md

@@ -1,8 +1,6 @@
 If you don't want to use _pydantic_'s `BaseModel` you can instead get the same data validation on standard
 [dataclasses](https://docs.python.org/3/library/dataclasses.html) (introduced in python 3.7).
 
-Dataclasses work in python 3.6 using the [dataclasses backport package](https://github.com/ericvsmith/dataclasses).
-
 ```py
 {!.tmp_examples/dataclasses_main.py!}
 ```

docs/usage/models.md

@@ -296,10 +296,6 @@ For example, in the example above, if `_fields_set` was not provided,
 
 Pydantic supports the creation of generic models to make it easier to reuse a common model structure.
 
-!!! warning
-    Generic models are only supported with python `>=3.7`, this is because of numerous subtle changes in how
-    generics are implemented between python 3.6 and python 3.7.
-
 In order to declare a generic model, you perform the following steps:
 
 * Declare one or more `typing.TypeVar` instances to use to parameterize your model.

mkdocs.yml

@@ -1,5 +1,5 @@
 site_name: pydantic
-site_description: Data validation and settings management using python 3.6 type hinting
+site_description: Data validation and settings management using python type hints
 strict: true
 site_url: https://pydantic-docs.helpmanual.io/
 

pydantic/config.py

@@ -1,6 +1,6 @@
 import json
 from enum import Enum
-from typing import TYPE_CHECKING, Any, Callable, Dict, Optional, Tuple, Type, Union
+from typing import TYPE_CHECKING, Any, Callable, Dict, ForwardRef, Optional, Tuple, Type, Union
 
 from .typing import AnyCallable
 from .utils import GetterDict
@@ -59,8 +59,7 @@ class BaseConfig:
     schema_extra: Union[Dict[str, Any], 'SchemaExtraCallable'] = {}
     json_loads: Callable[[str], Any] = json.loads
     json_dumps: Callable[..., str] = json.dumps
-    # key type should include ForwardRef, but that breaks with python3.6
-    json_encoders: Dict[Union[Type[Any], str], AnyCallable] = {}
+    json_encoders: Dict[Union[Type[Any], str, ForwardRef], AnyCallable] = {}
     underscore_attrs_are_private: bool = False
 
     # whether inherited models as fields should be reconstructed as base model

pydantic/fields.py

@@ -1135,7 +1135,6 @@ def is_complex(self) -> bool:
     def _type_display(self) -> PyObjectStr:
         t = display_as_type(self.type_)
 
-        # have to do this since display_as_type(self.outer_type_) is different (and wrong) on python 3.6
         if self.shape in MAPPING_LIKE_SHAPES:
             t = f'Mapping[{display_as_type(self.key_field.type_)}, {t}]'  # type: ignore
         elif self.shape == SHAPE_TUPLE:

pydantic/json.py

@@ -1,21 +1,14 @@
 import datetime
-import re
-import sys
 from collections import deque
 from decimal import Decimal
 from enum import Enum
 from ipaddress import IPv4Address, IPv4Interface, IPv4Network, IPv6Address, IPv6Interface, IPv6Network
 from pathlib import Path
+from re import Pattern
 from types import GeneratorType
 from typing import Any, Callable, Dict, Type, Union
 from uuid import UUID
 
-if sys.version_info >= (3, 7):
-    Pattern = re.Pattern
-else:
-    # python 3.6
-    Pattern = re.compile('a').__class__
-
 from .color import Color
 from .networks import NameEmail
 from .types import SecretBytes, SecretStr

pydantic/typing.py

@@ -1,11 +1,14 @@
 import sys
+from collections.abc import Callable
 from os import PathLike
 from typing import (  # type: ignore
     TYPE_CHECKING,
     AbstractSet,
     Any,
+    Callable as TypingCallable,
     ClassVar,
     Dict,
+    ForwardRef,
     Generator,
     Iterable,
     List,
@@ -36,28 +39,7 @@
     TypingGenericAlias = ()
 
 
-if sys.version_info < (3, 7):
-    if TYPE_CHECKING:
-
-        class ForwardRef:
-            def __init__(self, arg: Any):
-                pass
-
-            def _eval_type(self, globalns: Any, localns: Any) -> Any:
-                pass
-
-    else:
-        from typing import _ForwardRef as ForwardRef
-else:
-    from typing import ForwardRef
-
-
-if sys.version_info < (3, 7):
-
-    def evaluate_forwardref(type_: ForwardRef, globalns: Any, localns: Any) -> Any:
-        return type_._eval_type(globalns, localns)
-
-elif sys.version_info < (3, 9):
+if sys.version_info < (3, 9):
 
     def evaluate_forwardref(type_: ForwardRef, globalns: Any, localns: Any) -> Any:
         return type_._evaluate(globalns, localns)
@@ -72,7 +54,7 @@ def evaluate_forwardref(type_: ForwardRef, globalns: Any, localns: Any) -> Any:
 
 if sys.version_info < (3, 9):
     # Ensure we always get all the whole `Annotated` hint, not just the annotated type.
-    # For 3.6 to 3.8, `get_type_hints` doesn't recognize `typing_extensions.Annotated`,
+    # For 3.7 to 3.8, `get_type_hints` doesn't recognize `typing_extensions.Annotated`,
     # so it already returns the full annotation
     get_all_type_hints = get_type_hints
 
@@ -82,17 +64,8 @@ def get_all_type_hints(obj: Any, globalns: Any = None, localns: Any = None) -> A
         return get_type_hints(obj, globalns, localns, include_extras=True)
 
 
-if sys.version_info < (3, 7):
-    from typing import Callable as Callable
-
-    AnyCallable = Callable[..., Any]
-    NoArgAnyCallable = Callable[[], Any]
-else:
-    from collections.abc import Callable as Callable
-    from typing import Callable as TypingCallable
-
-    AnyCallable = TypingCallable[..., Any]
-    NoArgAnyCallable = TypingCallable[[], Any]
+AnyCallable = TypingCallable[..., Any]
+NoArgAnyCallable = TypingCallable[[], Any]
 
 
 # Annotated[...] is implemented by returning an instance of one of these classes, depending on
@@ -104,7 +77,8 @@ def get_all_type_hints(obj: Any, globalns: Any = None, localns: Any = None) -> A
 
     def get_origin(t: Type[Any]) -> Optional[Type[Any]]:
         if type(t).__name__ in AnnotatedTypeNames:
-            return cast(Type[Any], Annotated)  # mypy complains about _SpecialForm in py3.6
+            # weirdly this is a runtime requirement, as well as for mypy
+            return cast(Type[Any], Annotated)
         return getattr(t, '__origin__', None)
 
 else:
@@ -122,22 +96,7 @@ def get_origin(tp: Type[Any]) -> Optional[Type[Any]]:
         return _typing_get_origin(tp) or getattr(tp, '__origin__', None)
 
 
-if sys.version_info < (3, 7):  # noqa: C901 (ignore complexity)
-
-    def get_args(t: Type[Any]) -> Tuple[Any, ...]:
-        """Simplest get_args compatibility layer possible.
-
-        The Python 3.6 typing module does not have `_GenericAlias` so
-        this won't work for everything. In particular this will not
-        support the `generics` module (we don't support generic models in
-        python 3.6).
-
-        """
-        if type(t).__name__ in AnnotatedTypeNames:
-            return t.__args__ + t.__metadata__
-        return getattr(t, '__args__', ())
-
-elif sys.version_info < (3, 8):  # noqa: C901
+if sys.version_info < (3, 8):
     from typing import _GenericAlias
 
     def get_args(t: Type[Any]) -> Tuple[Any, ...]:
@@ -279,8 +238,8 @@ def is_union(tp: Optional[Type[Any]]) -> bool:
 
 
 if sys.version_info < (3, 8):
-    # Even though this implementation is slower, we need it for python 3.6/3.7:
-    # In python 3.6/3.7 "Literal" is not a builtin type and uses a different
+    # Even though this implementation is slower, we need it for python 3.7:
+    # In python 3.7 "Literal" is not a builtin type and uses a different
     # mechanism.
     # for this reason `Literal[None] is Literal[None]` evaluates to `False`,
     # breaking the faster implementation used for the other python versions.
@@ -348,10 +307,8 @@ def resolve_annotations(raw_annotations: Dict[str, Type[Any]], module_name: Opti
         if isinstance(value, str):
             if (3, 10) > sys.version_info >= (3, 9, 8) or sys.version_info >= (3, 10, 1):
                 value = ForwardRef(value, is_argument=False, is_class=True)
-            elif sys.version_info >= (3, 7):
-                value = ForwardRef(value, is_argument=False)
             else:
-                value = ForwardRef(value)
+                value = ForwardRef(value, is_argument=False)
         try:
             value = _eval_type(value, base_globals, None)
         except NameError:
@@ -365,21 +322,12 @@ def is_callable_type(type_: Type[Any]) -> bool:
     return type_ is Callable or get_origin(type_) is Callable
 
 
-if sys.version_info >= (3, 7):
+def is_literal_type(type_: Type[Any]) -> bool:
+    return Literal is not None and get_origin(type_) is Literal
 
-    def is_literal_type(type_: Type[Any]) -> bool:
-        return Literal is not None and get_origin(type_) is Literal
 
-    def literal_values(type_: Type[Any]) -> Tuple[Any, ...]:
-        return get_args(type_)
-
-else:
-
-    def is_literal_type(type_: Type[Any]) -> bool:
-        return Literal is not None and hasattr(type_, '__values__') and type_ == Literal[type_.__values__]
-
-    def literal_values(type_: Type[Any]) -> Tuple[Any, ...]:
-        return type_.__values__
+def literal_values(type_: Type[Any]) -> Tuple[Any, ...]:
+    return get_args(type_)
 
 
 def all_literal_values(type_: Type[Any]) -> Tuple[Any, ...]:
@@ -435,7 +383,7 @@ def _check_classvar(v: Optional[Type[Any]]) -> bool:
     if v is None:
         return False
 
-    return v.__class__ == ClassVar.__class__ and (sys.version_info < (3, 7) or getattr(v, '_name', None) == 'ClassVar')
+    return v.__class__ == ClassVar.__class__ and getattr(v, '_name', None) == 'ClassVar'
 
 
 def is_classvar(ann_type: Type[Any]) -> bool:
@@ -461,7 +409,7 @@ def update_field_forward_refs(field: 'ModelField', globalns: Any, localns: Any)
 def update_model_forward_refs(
     model: Type[Any],
     fields: Iterable['ModelField'],
-    json_encoders: Dict[Union[Type[Any], str], AnyCallable],
+    json_encoders: Dict[Union[Type[Any], str, ForwardRef], AnyCallable],
     localns: 'DictStrAny',
     exc_to_suppress: Tuple[Type[BaseException], ...] = (),
 ) -> None:
@@ -502,17 +450,14 @@ def get_class(type_: Type[Any]) -> Union[None, bool, Type[Any]]:
     Tries to get the class of a Type[T] annotation. Returns True if Type is used
     without brackets. Otherwise returns None.
     """
-    try:
-        origin = get_origin(type_)
-        if origin is None:  # Python 3.6
-            origin = type_
-        if issubclass(origin, Type):  # type: ignore
-            if not get_args(type_) or not isinstance(get_args(type_)[0], type):
-                return True
-            return get_args(type_)[0]
-    except (AttributeError, TypeError):
-        pass
-    return None
+    if get_origin(type_) is None:
+        return None
+
+    args = get_args(type_)
+    if not args or not isinstance(args[0], type):
+        return True
+    else:
+        return args[0]
 
 
 def get_sub_types(tp: Any) -> List[Any]:

setup.py

@@ -56,7 +56,7 @@ def extra(self):
         return '\n\n' + '\n'.join(sorted(self.links)) + '\n'
 
 
-description = 'Data validation and settings management using python 3.6 type hinting'
+description = 'Data validation and settings management using python type hints'
 THIS_DIR = Path(__file__).resolve().parent
 try:
     history = (THIS_DIR / 'HISTORY.md').read_text()
@@ -104,7 +104,6 @@ def extra(self):
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3 :: Only',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
@@ -127,10 +126,9 @@ def extra(self):
     license='MIT',
     packages=['pydantic'],
     package_data={'pydantic': ['py.typed']},
-    python_requires='>=3.6.1',
+    python_requires='>=3.7',
     zip_safe=False,  # https://mypy.readthedocs.io/en/latest/installed_packages.html
     install_requires=[
-        'dataclasses>=0.6;python_version<"3.7"',
         'typing-extensions>=3.7.4.3'
     ],
     extras_require={

tests/mypy/modules/plugin_fail.py

@@ -114,7 +114,7 @@ class Blah(BaseModel):
     fields_set: Optional[Set[str]] = None
 
 
-# Need to test generic checking here since generics don't work in 3.6, and plugin-success.py is executed
+# (comment to keep line numbers unchanged)
 T = TypeVar('T')