src/black/mode.py

   1 """Data structures configuring Black behavior.
   2
   3 Mostly around Python language feature support per version and Black configuration
   4 chosen by the user.
   5 """
   6
   7 from hashlib import sha256
   8 import sys
   9
  10 from dataclasses import dataclass, field
  11 from enum import Enum, auto
  12 from operator import attrgetter
  13 from typing import Dict, Set
  14 from warnings import warn
  15
  16 if sys.version_info < (3, 8):
  17     from typing_extensions import Final
  18 else:
  19     from typing import Final
  20
  21 from black.const import DEFAULT_LINE_LENGTH
  22
  23
  24 class TargetVersion(Enum):
  25     PY33 = 3
  26     PY34 = 4
  27     PY35 = 5
  28     PY36 = 6
  29     PY37 = 7
  30     PY38 = 8
  31     PY39 = 9
  32     PY310 = 10
  33     PY311 = 11
  34
  35
  36 class Feature(Enum):
  37     F_STRINGS = 2
  38     NUMERIC_UNDERSCORES = 3
  39     TRAILING_COMMA_IN_CALL = 4
  40     TRAILING_COMMA_IN_DEF = 5
  41     # The following two feature-flags are mutually exclusive, and exactly one should be
  42     # set for every version of python.
  43     ASYNC_IDENTIFIERS = 6
  44     ASYNC_KEYWORDS = 7
  45     ASSIGNMENT_EXPRESSIONS = 8
  46     POS_ONLY_ARGUMENTS = 9
  47     RELAXED_DECORATORS = 10
  48     PATTERN_MATCHING = 11
  49     UNPACKING_ON_FLOW = 12
  50     ANN_ASSIGN_EXTENDED_RHS = 13
  51     EXCEPT_STAR = 14
  52     VARIADIC_GENERICS = 15
  53     FORCE_OPTIONAL_PARENTHESES = 50
  54
  55     # __future__ flags
  56     FUTURE_ANNOTATIONS = 51
  57
  58
  59 FUTURE_FLAG_TO_FEATURE: Final = {
  60     "annotations": Feature.FUTURE_ANNOTATIONS,
  61 }
  62
  63
  64 VERSION_TO_FEATURES: Dict[TargetVersion, Set[Feature]] = {
  65     TargetVersion.PY33: {Feature.ASYNC_IDENTIFIERS},
  66     TargetVersion.PY34: {Feature.ASYNC_IDENTIFIERS},
  67     TargetVersion.PY35: {Feature.TRAILING_COMMA_IN_CALL, Feature.ASYNC_IDENTIFIERS},
  68     TargetVersion.PY36: {
  69         Feature.F_STRINGS,
  70         Feature.NUMERIC_UNDERSCORES,
  71         Feature.TRAILING_COMMA_IN_CALL,
  72         Feature.TRAILING_COMMA_IN_DEF,
  73         Feature.ASYNC_IDENTIFIERS,
  74     },
  75     TargetVersion.PY37: {
  76         Feature.F_STRINGS,
  77         Feature.NUMERIC_UNDERSCORES,
  78         Feature.TRAILING_COMMA_IN_CALL,
  79         Feature.TRAILING_COMMA_IN_DEF,
  80         Feature.ASYNC_KEYWORDS,
  81         Feature.FUTURE_ANNOTATIONS,
  82     },
  83     TargetVersion.PY38: {
  84         Feature.F_STRINGS,
  85         Feature.NUMERIC_UNDERSCORES,
  86         Feature.TRAILING_COMMA_IN_CALL,
  87         Feature.TRAILING_COMMA_IN_DEF,
  88         Feature.ASYNC_KEYWORDS,
  89         Feature.FUTURE_ANNOTATIONS,
  90         Feature.ASSIGNMENT_EXPRESSIONS,
  91         Feature.POS_ONLY_ARGUMENTS,
  92         Feature.UNPACKING_ON_FLOW,
  93         Feature.ANN_ASSIGN_EXTENDED_RHS,
  94     },
  95     TargetVersion.PY39: {
  96         Feature.F_STRINGS,
  97         Feature.NUMERIC_UNDERSCORES,
  98         Feature.TRAILING_COMMA_IN_CALL,
  99         Feature.TRAILING_COMMA_IN_DEF,
 100         Feature.ASYNC_KEYWORDS,
 101         Feature.FUTURE_ANNOTATIONS,
 102         Feature.ASSIGNMENT_EXPRESSIONS,
 103         Feature.RELAXED_DECORATORS,
 104         Feature.POS_ONLY_ARGUMENTS,
 105         Feature.UNPACKING_ON_FLOW,
 106         Feature.ANN_ASSIGN_EXTENDED_RHS,
 107     },
 108     TargetVersion.PY310: {
 109         Feature.F_STRINGS,
 110         Feature.NUMERIC_UNDERSCORES,
 111         Feature.TRAILING_COMMA_IN_CALL,
 112         Feature.TRAILING_COMMA_IN_DEF,
 113         Feature.ASYNC_KEYWORDS,
 114         Feature.FUTURE_ANNOTATIONS,
 115         Feature.ASSIGNMENT_EXPRESSIONS,
 116         Feature.RELAXED_DECORATORS,
 117         Feature.POS_ONLY_ARGUMENTS,
 118         Feature.UNPACKING_ON_FLOW,
 119         Feature.ANN_ASSIGN_EXTENDED_RHS,
 120         Feature.PATTERN_MATCHING,
 121     },
 122     TargetVersion.PY311: {
 123         Feature.F_STRINGS,
 124         Feature.NUMERIC_UNDERSCORES,
 125         Feature.TRAILING_COMMA_IN_CALL,
 126         Feature.TRAILING_COMMA_IN_DEF,
 127         Feature.ASYNC_KEYWORDS,
 128         Feature.FUTURE_ANNOTATIONS,
 129         Feature.ASSIGNMENT_EXPRESSIONS,
 130         Feature.RELAXED_DECORATORS,
 131         Feature.POS_ONLY_ARGUMENTS,
 132         Feature.UNPACKING_ON_FLOW,
 133         Feature.ANN_ASSIGN_EXTENDED_RHS,
 134         Feature.PATTERN_MATCHING,
 135         Feature.EXCEPT_STAR,
 136         Feature.VARIADIC_GENERICS,
 137     },
 138 }
 139
 140
 141 def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> bool:
 142     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 143
 144
 145 class Preview(Enum):
 146     """Individual preview style features."""
 147
 148     string_processing = auto()
 149     remove_redundant_parens = auto()
 150     one_element_subscript = auto()
 151     annotation_parens = auto()
 152     long_docstring_quotes_on_newline = auto()
 153     remove_block_trailing_newline = auto()
 154
 155
 156 class Deprecated(UserWarning):
 157     """Visible deprecation warning."""
 158
 159
 160 @dataclass
 161 class Mode:
 162     target_versions: Set[TargetVersion] = field(default_factory=set)
 163     line_length: int = DEFAULT_LINE_LENGTH
 164     string_normalization: bool = True
 165     is_pyi: bool = False
 166     is_ipynb: bool = False
 167     magic_trailing_comma: bool = True
 168     experimental_string_processing: bool = False
 169     python_cell_magics: Set[str] = field(default_factory=set)
 170     preview: bool = False
 171
 172     def __post_init__(self) -> None:
 173         if self.experimental_string_processing:
 174             warn(
 175                 "`experimental string processing` has been included in `preview`"
 176                 " and deprecated. Use `preview` instead.",
 177                 Deprecated,
 178             )
 179
 180     def __contains__(self, feature: Preview) -> bool:
 181         """
 182         Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
 183
 184         The argument is not checked and features are not differentiated.
 185         They only exist to make development easier by clarifying intent.
 186         """
 187         if feature is Preview.string_processing:
 188             return self.preview or self.experimental_string_processing
 189         return self.preview
 190
 191     def get_cache_key(self) -> str:
 192         if self.target_versions:
 193             version_str = ",".join(
 194                 str(version.value)
 195                 for version in sorted(self.target_versions, key=attrgetter("value"))
 196             )
 197         else:
 198             version_str = "-"
 199         parts = [
 200             version_str,
 201             str(self.line_length),
 202             str(int(self.string_normalization)),
 203             str(int(self.is_pyi)),
 204             str(int(self.is_ipynb)),
 205             str(int(self.magic_trailing_comma)),
 206             str(int(self.experimental_string_processing)),
 207             str(int(self.preview)),
 208             sha256((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
 209         ]
 210         return ".".join(parts)