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     DEBUG_F_STRINGS = 16
  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.DEBUG_F_STRINGS,
  86         Feature.NUMERIC_UNDERSCORES,
  87         Feature.TRAILING_COMMA_IN_CALL,
  88         Feature.TRAILING_COMMA_IN_DEF,
  89         Feature.ASYNC_KEYWORDS,
  90         Feature.FUTURE_ANNOTATIONS,
  91         Feature.ASSIGNMENT_EXPRESSIONS,
  92         Feature.POS_ONLY_ARGUMENTS,
  93         Feature.UNPACKING_ON_FLOW,
  94         Feature.ANN_ASSIGN_EXTENDED_RHS,
  95     },
  96     TargetVersion.PY39: {
  97         Feature.F_STRINGS,
  98         Feature.DEBUG_F_STRINGS,
  99         Feature.NUMERIC_UNDERSCORES,
 100         Feature.TRAILING_COMMA_IN_CALL,
 101         Feature.TRAILING_COMMA_IN_DEF,
 102         Feature.ASYNC_KEYWORDS,
 103         Feature.FUTURE_ANNOTATIONS,
 104         Feature.ASSIGNMENT_EXPRESSIONS,
 105         Feature.RELAXED_DECORATORS,
 106         Feature.POS_ONLY_ARGUMENTS,
 107         Feature.UNPACKING_ON_FLOW,
 108         Feature.ANN_ASSIGN_EXTENDED_RHS,
 109     },
 110     TargetVersion.PY310: {
 111         Feature.F_STRINGS,
 112         Feature.DEBUG_F_STRINGS,
 113         Feature.NUMERIC_UNDERSCORES,
 114         Feature.TRAILING_COMMA_IN_CALL,
 115         Feature.TRAILING_COMMA_IN_DEF,
 116         Feature.ASYNC_KEYWORDS,
 117         Feature.FUTURE_ANNOTATIONS,
 118         Feature.ASSIGNMENT_EXPRESSIONS,
 119         Feature.RELAXED_DECORATORS,
 120         Feature.POS_ONLY_ARGUMENTS,
 121         Feature.UNPACKING_ON_FLOW,
 122         Feature.ANN_ASSIGN_EXTENDED_RHS,
 123         Feature.PATTERN_MATCHING,
 124     },
 125     TargetVersion.PY311: {
 126         Feature.F_STRINGS,
 127         Feature.DEBUG_F_STRINGS,
 128         Feature.NUMERIC_UNDERSCORES,
 129         Feature.TRAILING_COMMA_IN_CALL,
 130         Feature.TRAILING_COMMA_IN_DEF,
 131         Feature.ASYNC_KEYWORDS,
 132         Feature.FUTURE_ANNOTATIONS,
 133         Feature.ASSIGNMENT_EXPRESSIONS,
 134         Feature.RELAXED_DECORATORS,
 135         Feature.POS_ONLY_ARGUMENTS,
 136         Feature.UNPACKING_ON_FLOW,
 137         Feature.ANN_ASSIGN_EXTENDED_RHS,
 138         Feature.PATTERN_MATCHING,
 139         Feature.EXCEPT_STAR,
 140         Feature.VARIADIC_GENERICS,
 141     },
 142 }
 143
 144
 145 def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> bool:
 146     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 147
 148
 149 class Preview(Enum):
 150     """Individual preview style features."""
 151
 152     annotation_parens = auto()
 153     long_docstring_quotes_on_newline = auto()
 154     normalize_docstring_quotes_and_prefixes_properly = auto()
 155     one_element_subscript = auto()
 156     remove_block_trailing_newline = auto()
 157     remove_redundant_parens = auto()
 158     string_processing = auto()
 159     skip_magic_trailing_comma_in_subscript = auto()
 160
 161
 162 class Deprecated(UserWarning):
 163     """Visible deprecation warning."""
 164
 165
 166 @dataclass
 167 class Mode:
 168     target_versions: Set[TargetVersion] = field(default_factory=set)
 169     line_length: int = DEFAULT_LINE_LENGTH
 170     string_normalization: bool = True
 171     is_pyi: bool = False
 172     is_ipynb: bool = False
 173     magic_trailing_comma: bool = True
 174     experimental_string_processing: bool = False
 175     python_cell_magics: Set[str] = field(default_factory=set)
 176     preview: bool = False
 177
 178     def __post_init__(self) -> None:
 179         if self.experimental_string_processing:
 180             warn(
 181                 "`experimental string processing` has been included in `preview`"
 182                 " and deprecated. Use `preview` instead.",
 183                 Deprecated,
 184             )
 185
 186     def __contains__(self, feature: Preview) -> bool:
 187         """
 188         Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
 189
 190         The argument is not checked and features are not differentiated.
 191         They only exist to make development easier by clarifying intent.
 192         """
 193         if feature is Preview.string_processing:
 194             return self.preview or self.experimental_string_processing
 195         return self.preview
 196
 197     def get_cache_key(self) -> str:
 198         if self.target_versions:
 199             version_str = ",".join(
 200                 str(version.value)
 201                 for version in sorted(self.target_versions, key=attrgetter("value"))
 202             )
 203         else:
 204             version_str = "-"
 205         parts = [
 206             version_str,
 207             str(self.line_length),
 208             str(int(self.string_normalization)),
 209             str(int(self.is_pyi)),
 210             str(int(self.is_ipynb)),
 211             str(int(self.magic_trailing_comma)),
 212             str(int(self.experimental_string_processing)),
 213             str(int(self.preview)),
 214             sha256((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
 215         ]
 216         return ".".join(parts)