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     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     },
 136 }
 137
 138
 139 def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> bool:
 140     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 141
 142
 143 class Preview(Enum):
 144     """Individual preview style features."""
 145
 146     string_processing = auto()
 147     remove_redundant_parens = auto()
 148     one_element_subscript = auto()
 149     annotation_parens = auto()
 150     long_docstring_quotes_on_newline = auto()
 151
 152
 153 class Deprecated(UserWarning):
 154     """Visible deprecation warning."""
 155
 156
 157 @dataclass
 158 class Mode:
 159     target_versions: Set[TargetVersion] = field(default_factory=set)
 160     line_length: int = DEFAULT_LINE_LENGTH
 161     string_normalization: bool = True
 162     is_pyi: bool = False
 163     is_ipynb: bool = False
 164     magic_trailing_comma: bool = True
 165     experimental_string_processing: bool = False
 166     python_cell_magics: Set[str] = field(default_factory=set)
 167     preview: bool = False
 168
 169     def __post_init__(self) -> None:
 170         if self.experimental_string_processing:
 171             warn(
 172                 "`experimental string processing` has been included in `preview`"
 173                 " and deprecated. Use `preview` instead.",
 174                 Deprecated,
 175             )
 176
 177     def __contains__(self, feature: Preview) -> bool:
 178         """
 179         Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
 180
 181         The argument is not checked and features are not differentiated.
 182         They only exist to make development easier by clarifying intent.
 183         """
 184         if feature is Preview.string_processing:
 185             return self.preview or self.experimental_string_processing
 186         return self.preview
 187
 188     def get_cache_key(self) -> str:
 189         if self.target_versions:
 190             version_str = ",".join(
 191                 str(version.value)
 192                 for version in sorted(self.target_versions, key=attrgetter("value"))
 193             )
 194         else:
 195             version_str = "-"
 196         parts = [
 197             version_str,
 198             str(self.line_length),
 199             str(int(self.string_normalization)),
 200             str(int(self.is_pyi)),
 201             str(int(self.is_ipynb)),
 202             str(int(self.magic_trailing_comma)),
 203             str(int(self.experimental_string_processing)),
 204             str(int(self.preview)),
 205             sha256((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
 206         ]
 207         return ".".join(parts)