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
  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     FORCE_OPTIONAL_PARENTHESES = 50
  51
  52     # __future__ flags
  53     FUTURE_ANNOTATIONS = 51
  54
  55
  56 FUTURE_FLAG_TO_FEATURE: Final = {
  57     "annotations": Feature.FUTURE_ANNOTATIONS,
  58 }
  59
  60
  61 VERSION_TO_FEATURES: Dict[TargetVersion, Set[Feature]] = {
  62     TargetVersion.PY33: {Feature.ASYNC_IDENTIFIERS},
  63     TargetVersion.PY34: {Feature.ASYNC_IDENTIFIERS},
  64     TargetVersion.PY35: {Feature.TRAILING_COMMA_IN_CALL, Feature.ASYNC_IDENTIFIERS},
  65     TargetVersion.PY36: {
  66         Feature.F_STRINGS,
  67         Feature.NUMERIC_UNDERSCORES,
  68         Feature.TRAILING_COMMA_IN_CALL,
  69         Feature.TRAILING_COMMA_IN_DEF,
  70         Feature.ASYNC_IDENTIFIERS,
  71     },
  72     TargetVersion.PY37: {
  73         Feature.F_STRINGS,
  74         Feature.NUMERIC_UNDERSCORES,
  75         Feature.TRAILING_COMMA_IN_CALL,
  76         Feature.TRAILING_COMMA_IN_DEF,
  77         Feature.ASYNC_KEYWORDS,
  78         Feature.FUTURE_ANNOTATIONS,
  79     },
  80     TargetVersion.PY38: {
  81         Feature.F_STRINGS,
  82         Feature.NUMERIC_UNDERSCORES,
  83         Feature.TRAILING_COMMA_IN_CALL,
  84         Feature.TRAILING_COMMA_IN_DEF,
  85         Feature.ASYNC_KEYWORDS,
  86         Feature.FUTURE_ANNOTATIONS,
  87         Feature.ASSIGNMENT_EXPRESSIONS,
  88         Feature.POS_ONLY_ARGUMENTS,
  89         Feature.UNPACKING_ON_FLOW,
  90         Feature.ANN_ASSIGN_EXTENDED_RHS,
  91     },
  92     TargetVersion.PY39: {
  93         Feature.F_STRINGS,
  94         Feature.NUMERIC_UNDERSCORES,
  95         Feature.TRAILING_COMMA_IN_CALL,
  96         Feature.TRAILING_COMMA_IN_DEF,
  97         Feature.ASYNC_KEYWORDS,
  98         Feature.FUTURE_ANNOTATIONS,
  99         Feature.ASSIGNMENT_EXPRESSIONS,
 100         Feature.RELAXED_DECORATORS,
 101         Feature.POS_ONLY_ARGUMENTS,
 102         Feature.UNPACKING_ON_FLOW,
 103         Feature.ANN_ASSIGN_EXTENDED_RHS,
 104     },
 105     TargetVersion.PY310: {
 106         Feature.F_STRINGS,
 107         Feature.NUMERIC_UNDERSCORES,
 108         Feature.TRAILING_COMMA_IN_CALL,
 109         Feature.TRAILING_COMMA_IN_DEF,
 110         Feature.ASYNC_KEYWORDS,
 111         Feature.FUTURE_ANNOTATIONS,
 112         Feature.ASSIGNMENT_EXPRESSIONS,
 113         Feature.RELAXED_DECORATORS,
 114         Feature.POS_ONLY_ARGUMENTS,
 115         Feature.UNPACKING_ON_FLOW,
 116         Feature.ANN_ASSIGN_EXTENDED_RHS,
 117         Feature.PATTERN_MATCHING,
 118     },
 119 }
 120
 121
 122 def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> bool:
 123     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 124
 125
 126 class Preview(Enum):
 127     """Individual preview style features."""
 128
 129     string_processing = auto()
 130
 131
 132 class Deprecated(UserWarning):
 133     """Visible deprecation warning."""
 134
 135
 136 @dataclass
 137 class Mode:
 138     target_versions: Set[TargetVersion] = field(default_factory=set)
 139     line_length: int = DEFAULT_LINE_LENGTH
 140     string_normalization: bool = True
 141     is_pyi: bool = False
 142     is_ipynb: bool = False
 143     magic_trailing_comma: bool = True
 144     experimental_string_processing: bool = False
 145     python_cell_magics: Set[str] = field(default_factory=set)
 146     preview: bool = False
 147
 148     def __post_init__(self) -> None:
 149         if self.experimental_string_processing:
 150             warn(
 151                 "`experimental string processing` has been included in `preview`"
 152                 " and deprecated. Use `preview` instead.",
 153                 Deprecated,
 154             )
 155
 156     def __contains__(self, feature: Preview) -> bool:
 157         """
 158         Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
 159
 160         The argument is not checked and features are not differentiated.
 161         They only exist to make development easier by clarifying intent.
 162         """
 163         if feature is Preview.string_processing:
 164             return self.preview or self.experimental_string_processing
 165         # TODO: Remove type ignore comment once preview contains more features
 166         #  than just ESP
 167         return self.preview  # type: ignore
 168
 169     def get_cache_key(self) -> str:
 170         if self.target_versions:
 171             version_str = ",".join(
 172                 str(version.value)
 173                 for version in sorted(self.target_versions, key=attrgetter("value"))
 174             )
 175         else:
 176             version_str = "-"
 177         parts = [
 178             version_str,
 179             str(self.line_length),
 180             str(int(self.string_normalization)),
 181             str(int(self.is_pyi)),
 182             str(int(self.is_ipynb)),
 183             str(int(self.magic_trailing_comma)),
 184             str(int(self.experimental_string_processing)),
 185             str(int(self.preview)),
 186             sha256((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
 187         ]
 188         return ".".join(parts)