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 md5
   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     hug_simple_powers = auto()
 131
 132
 133 class Deprecated(UserWarning):
 134     """Visible deprecation warning."""
 135
 136
 137 @dataclass
 138 class Mode:
 139     target_versions: Set[TargetVersion] = field(default_factory=set)
 140     line_length: int = DEFAULT_LINE_LENGTH
 141     string_normalization: bool = True
 142     is_pyi: bool = False
 143     is_ipynb: bool = False
 144     magic_trailing_comma: bool = True
 145     experimental_string_processing: bool = False
 146     python_cell_magics: Set[str] = field(default_factory=set)
 147     preview: bool = False
 148
 149     def __post_init__(self) -> None:
 150         if self.experimental_string_processing:
 151             warn(
 152                 "`experimental string processing` has been included in `preview`"
 153                 " and deprecated. Use `preview` instead.",
 154                 Deprecated,
 155             )
 156
 157     def __contains__(self, feature: Preview) -> bool:
 158         """
 159         Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
 160
 161         The argument is not checked and features are not differentiated.
 162         They only exist to make development easier by clarifying intent.
 163         """
 164         if feature is Preview.string_processing:
 165             return self.preview or self.experimental_string_processing
 166         return self.preview
 167
 168     def get_cache_key(self) -> str:
 169         if self.target_versions:
 170             version_str = ",".join(
 171                 str(version.value)
 172                 for version in sorted(self.target_versions, key=attrgetter("value"))
 173             )
 174         else:
 175             version_str = "-"
 176         parts = [
 177             version_str,
 178             str(self.line_length),
 179             str(int(self.string_normalization)),
 180             str(int(self.is_pyi)),
 181             str(int(self.is_ipynb)),
 182             str(int(self.magic_trailing_comma)),
 183             str(int(self.experimental_string_processing)),
 184             str(int(self.preview)),
 185             md5((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
 186         ]
 187         return ".".join(parts)