Switch from toml to tomli for TOML v1 support (#10824)

Author: hukkin

build-requirements.txt

@@ -1,3 +1,2 @@
 -r mypy-requirements.txt
 types-typed-ast>=1.4.0,<1.5.0
-types-toml>=0.0

mypy-requirements.txt

@@ -1,4 +1,4 @@
 typing_extensions>=3.7.4
 mypy_extensions>=0.4.3,<0.5.0
 typed_ast>=1.4.0,<1.5.0
-toml
+tomli<2.0.0

mypy/config_parser.py

@@ -1,15 +1,14 @@
 import argparse
-from collections import OrderedDict
 import configparser
 import glob as fileglob
 from io import StringIO
 import os
 import re
 import sys
 
-import toml
+import tomli
 from typing import (Any, Callable, Dict, List, Mapping, MutableMapping,  Optional, Sequence,
-                    TextIO, Tuple, Union, cast)
+                    TextIO, Tuple, Union)
 from typing_extensions import Final
 
 from mypy import defaults
@@ -169,20 +168,20 @@ def parse_config_file(options: Options, set_strict_flags: Callable[[], None],
             continue
         try:
             if is_toml(config_file):
-                toml_data = cast("OrderedDict[str, Any]",
-                                 toml.load(config_file, _dict=OrderedDict))
+                with open(config_file, encoding="utf-8") as f:
+                    toml_data = tomli.load(f)
                 # Filter down to just mypy relevant toml keys
                 toml_data = toml_data.get('tool', {})
                 if 'mypy' not in toml_data:
                     continue
-                toml_data = OrderedDict({'mypy': toml_data['mypy']})
+                toml_data = {'mypy': toml_data['mypy']}
                 parser: MutableMapping[str, Any] = destructure_overrides(toml_data)
                 config_types = toml_config_types
             else:
                 config_parser.read(config_file)
                 parser = config_parser
                 config_types = ini_config_types
-        except (toml.TomlDecodeError, configparser.Error, ConfigTOMLValueError) as err:
+        except (tomli.TOMLDecodeError, configparser.Error, ConfigTOMLValueError) as err:
             print("%s: %s" % (config_file, err), file=stderr)
         else:
             if config_file in defaults.SHARED_CONFIG_FILES and 'mypy' not in parser:
@@ -252,7 +251,7 @@ def is_toml(filename: str) -> bool:
     return filename.lower().endswith('.toml')
 
 
-def destructure_overrides(toml_data: "OrderedDict[str, Any]") -> "OrderedDict[str, Any]":
+def destructure_overrides(toml_data: Dict[str, Any]) -> Dict[str, Any]:
     """Take the new [[tool.mypy.overrides]] section array in the pyproject.toml file,
     and convert it back to a flatter structure that the existing config_parser can handle.
 

mypy/modulefinder.py

@@ -433,9 +433,9 @@ def _is_compatible_stub_package(self, stub_dir: str) -> bool:
         metadata_fnam = os.path.join(stub_dir, 'METADATA.toml')
         if os.path.isfile(metadata_fnam):
             # Delay import for a possible minor performance win.
-            import toml
-            with open(metadata_fnam, 'r') as f:
-                metadata = toml.load(f)
+            import tomli
+            with open(metadata_fnam, 'r', encoding="utf-8") as f:
+                metadata = tomli.load(f)
             if self.python_major_ver == 2:
                 return bool(metadata.get('python2', False))
             else:

setup.py

@@ -193,7 +193,7 @@ def run(self):
       install_requires=["typed_ast >= 1.4.0, < 1.5.0; python_version<'3.8'",
                         'typing_extensions>=3.7.4',
                         'mypy_extensions >= 0.4.3, < 0.5.0',
-                        'toml',
+                        'tomli<2.0.0',
                         ],
       # Same here.
       extras_require={'dmypy': 'psutil >= 4.0', 'python2': 'typed_ast >= 1.4.0, < 1.5.0'},