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 import sys
   8 from dataclasses import dataclass, field
   9 from enum import Enum, auto
  10 from hashlib import sha256
  11 from operator import attrgetter
  12 from typing import Dict, Set
  13 from warnings import warn
  14
  15 if sys.version_info < (3, 8):
  16     from typing_extensions import Final
  17 else:
  18     from typing import Final
  19
  20 from black.const import DEFAULT_LINE_LENGTH
  21
  22
  23 class TargetVersion(Enum):
  24     PY33 = 3
  25     PY34 = 4
  26     PY35 = 5
  27     PY36 = 6
  28     PY37 = 7
  29     PY38 = 8
  30     PY39 = 9
  31     PY310 = 10
  32     PY311 = 11
  33
  34
  35 class Feature(Enum):
  36     F_STRINGS = 2
  37     NUMERIC_UNDERSCORES = 3
  38     TRAILING_COMMA_IN_CALL = 4
  39     TRAILING_COMMA_IN_DEF = 5
  40     # The following two feature-flags are mutually exclusive, and exactly one should be
  41     # set for every version of python.
  42     ASYNC_IDENTIFIERS = 6
  43     ASYNC_KEYWORDS = 7
  44     ASSIGNMENT_EXPRESSIONS = 8
  45     POS_ONLY_ARGUMENTS = 9
  46     RELAXED_DECORATORS = 10
  47     PATTERN_MATCHING = 11
  48     UNPACKING_ON_FLOW = 12
  49     ANN_ASSIGN_EXTENDED_RHS = 13
  50     EXCEPT_STAR = 14
  51     VARIADIC_GENERICS = 15
  52     FORCE_OPTIONAL_PARENTHESES = 50
  53
  54     # __future__ flags
  55     FUTURE_ANNOTATIONS = 51
  56
  57
  58 FUTURE_FLAG_TO_FEATURE: Final = {
  59     "annotations": Feature.FUTURE_ANNOTATIONS,
  60 }
  61
  62
  63 VERSION_TO_FEATURES: Dict[TargetVersion, Set[Feature]] = {
  64     TargetVersion.PY33: {Feature.ASYNC_IDENTIFIERS},
  65     TargetVersion.PY34: {Feature.ASYNC_IDENTIFIERS},
  66     TargetVersion.PY35: {Feature.TRAILING_COMMA_IN_CALL, Feature.ASYNC_IDENTIFIERS},
  67     TargetVersion.PY36: {
  68         Feature.F_STRINGS,
  69         Feature.NUMERIC_UNDERSCORES,
  70         Feature.TRAILING_COMMA_IN_CALL,
  71         Feature.TRAILING_COMMA_IN_DEF,
  72         Feature.ASYNC_IDENTIFIERS,
  73     },
  74     TargetVersion.PY37: {
  75         Feature.F_STRINGS,
  76         Feature.NUMERIC_UNDERSCORES,
  77         Feature.TRAILING_COMMA_IN_CALL,
  78         Feature.TRAILING_COMMA_IN_DEF,
  79         Feature.ASYNC_KEYWORDS,
  80         Feature.FUTURE_ANNOTATIONS,
  81     },
  82     TargetVersion.PY38: {
  83         Feature.F_STRINGS,
  84         Feature.NUMERIC_UNDERSCORES,
  85         Feature.TRAILING_COMMA_IN_CALL,
  86         Feature.TRAILING_COMMA_IN_DEF,
  87         Feature.ASYNC_KEYWORDS,
  88         Feature.FUTURE_ANNOTATIONS,
  89         Feature.ASSIGNMENT_EXPRESSIONS,
  90         Feature.POS_ONLY_ARGUMENTS,
  91         Feature.UNPACKING_ON_FLOW,
  92         Feature.ANN_ASSIGN_EXTENDED_RHS,
  93     },
  94     TargetVersion.PY39: {
  95         Feature.F_STRINGS,
  96         Feature.NUMERIC_UNDERSCORES,
  97         Feature.TRAILING_COMMA_IN_CALL,
  98         Feature.TRAILING_COMMA_IN_DEF,
  99         Feature.ASYNC_KEYWORDS,
 100         Feature.FUTURE_ANNOTATIONS,
 101         Feature.ASSIGNMENT_EXPRESSIONS,
 102         Feature.RELAXED_DECORATORS,
 103         Feature.POS_ONLY_ARGUMENTS,
 104         Feature.UNPACKING_ON_FLOW,
 105         Feature.ANN_ASSIGN_EXTENDED_RHS,
 106     },
 107     TargetVersion.PY310: {
 108         Feature.F_STRINGS,
 109         Feature.NUMERIC_UNDERSCORES,
 110         Feature.TRAILING_COMMA_IN_CALL,
 111         Feature.TRAILING_COMMA_IN_DEF,
 112         Feature.ASYNC_KEYWORDS,
 113         Feature.FUTURE_ANNOTATIONS,
 114         Feature.ASSIGNMENT_EXPRESSIONS,
 115         Feature.RELAXED_DECORATORS,
 116         Feature.POS_ONLY_ARGUMENTS,
 117         Feature.UNPACKING_ON_FLOW,
 118         Feature.ANN_ASSIGN_EXTENDED_RHS,
 119         Feature.PATTERN_MATCHING,
 120     },
 121     TargetVersion.PY311: {
 122         Feature.F_STRINGS,
 123         Feature.NUMERIC_UNDERSCORES,
 124         Feature.TRAILING_COMMA_IN_CALL,
 125         Feature.TRAILING_COMMA_IN_DEF,
 126         Feature.ASYNC_KEYWORDS,
 127         Feature.FUTURE_ANNOTATIONS,
 128         Feature.ASSIGNMENT_EXPRESSIONS,
 129         Feature.RELAXED_DECORATORS,
 130         Feature.POS_ONLY_ARGUMENTS,
 131         Feature.UNPACKING_ON_FLOW,
 132         Feature.ANN_ASSIGN_EXTENDED_RHS,
 133         Feature.PATTERN_MATCHING,
 134         Feature.EXCEPT_STAR,
 135         Feature.VARIADIC_GENERICS,
 136     },
 137 }
 138
 139
 140 def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> bool:
 141     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 142
 143
 144 class Preview(Enum):
 145     """Individual preview style features."""
 146
 147     annotation_parens = auto()
 148     long_docstring_quotes_on_newline = auto()
 149     normalize_docstring_quotes_and_prefixes_properly = auto()
 150     one_element_subscript = auto()
 151     remove_block_trailing_newline = auto()
 152     remove_redundant_parens = auto()
 153     string_processing = 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)