Toml support for pydantic-mypy plugin config (pydantic#2908)

* add toml reader

* fix path

* skip configparser step

* fix quotes

* full pyproject.toml check

* add doc note

* cleaner formatting, raise ValueError for non-bool

* fix tests

* add bad config test case

* add changelog file.

* bump mypy to 0.902

* tweak change MD, fix formatting in requirements

* import check around toml

* switch to tomli for parsing to match mypy dependency

* import check around toml/tomli

* add note on tomli usage

* more succinct changelog entry

* fix quotes in changelog

* linting fixes, remove unnecessary stub install

* mypy checks on mypy plugin file

* wrongly placed pragma no cover

Co-authored-by: PrettyWood <em.jolibois@gmail.com>

changes/2908-jrwalk.md

@@ -1,4 +1 @@
-Adds configuration logic to the `PydanticPluginConfig` constructor, enabling parsing of the configuration slots from `pyproject.toml` for `mypy>0.900`.
-Adds test cases for parsing config from `pyproject.toml`, including a failing case for a non-boolean value (this matches the old `ConfigParser` behavior of raising a `ValueError` on failures in the `getboolean` method).
-Increases the pinned version to `mypy==0.902` in the test suite, and includes formatting changes to prior test cases to match.
-Adds documentation change reflecting `pyproject.toml` configuration for plugin.
+Make `pydantic-mypy` plugin compatible with `pyproject.toml` configuration, consistent with `mypy` changes. See the [doc](https://pydantic-docs.helpmanual.io/mypy_plugin/#configuring-the-plugin) for more information.

pydantic/mypy.py

@@ -1,7 +1,17 @@
 from configparser import ConfigParser
 from typing import Any, Callable, Dict, List, Optional, Set, Tuple, Type as TypingType, Union
 
-import toml
+try:
+    import toml
+except ImportError:  # pragma: no cover
+    # future-proofing for upcoming `mypy` releases which will switch dependencies
+    try:
+        import tomli as toml  # type: ignore
+    except ImportError:
+        import warnings
+
+        warnings.warn('No TOML parser installed, cannot read configuration from `pyproject.toml`.')
+        toml = None  # type: ignore
 from mypy.errorcodes import ErrorCode
 from mypy.nodes import (
     ARG_NAMED,
@@ -112,7 +122,7 @@ def __init__(self, options: Options) -> None:
         if options.config_file is None:  # pragma: no cover
             return
 
-        if options.config_file.endswith('.toml'):
+        if toml and options.config_file.endswith('.toml'):
             with open(options.config_file, 'r') as rf:
                 config = toml.load(rf).get('tool', {}).get('pydantic-mypy', {})
             for key in self.__slots__:

tests/mypy/test_mypy.py

@@ -37,7 +37,7 @@
     ('pyproject-plugin.toml', 'plugin_success.py', None),
     ('pyproject-plugin.toml', 'plugin_fail.py', 'plugin-fail.txt'),
     ('pyproject-plugin-strict.toml', 'plugin_success.py', 'plugin-success-strict.txt'),
-    ('pyproject-plugin-strict.toml', 'plugin_fail.py', 'plugin-fail-strict.txt')
+    ('pyproject-plugin-strict.toml', 'plugin_fail.py', 'plugin-fail-strict.txt'),
 ]
 executable_modules = list({fname[:-3] for _, fname, out_fname in cases if out_fname is None})
 

tests/requirements-linting.txt

@@ -4,6 +4,7 @@ flake8-quotes==3.3.0
 hypothesis==6.17.4
 isort==5.9.3
 mypy==0.910
+types-toml==0.1.5
 pycodestyle==2.7.0
 pyflakes==2.3.1
 twine==3.4.2