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     VARIADIC_GENERICS = 15
  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.NUMERIC_UNDERSCORES,
  86         Feature.TRAILING_COMMA_IN_CALL,
  87         Feature.TRAILING_COMMA_IN_DEF,
  88         Feature.ASYNC_KEYWORDS,
  89         Feature.FUTURE_ANNOTATIONS,
  90         Feature.ASSIGNMENT_EXPRESSIONS,
  91         Feature.POS_ONLY_ARGUMENTS,
  92         Feature.UNPACKING_ON_FLOW,
  93         Feature.ANN_ASSIGN_EXTENDED_RHS,
  94     },
  95     TargetVersion.PY39: {
  96         Feature.F_STRINGS,
  97         Feature.NUMERIC_UNDERSCORES,
  98         Feature.TRAILING_COMMA_IN_CALL,
  99         Feature.TRAILING_COMMA_IN_DEF,
 100         Feature.ASYNC_KEYWORDS,
 101         Feature.FUTURE_ANNOTATIONS,
 102         Feature.ASSIGNMENT_EXPRESSIONS,
 103         Feature.RELAXED_DECORATORS,
 104         Feature.POS_ONLY_ARGUMENTS,
 105         Feature.UNPACKING_ON_FLOW,
 106         Feature.ANN_ASSIGN_EXTENDED_RHS,
 107     },
 108     TargetVersion.PY310: {
 109         Feature.F_STRINGS,
 110         Feature.NUMERIC_UNDERSCORES,
 111         Feature.TRAILING_COMMA_IN_CALL,
 112         Feature.TRAILING_COMMA_IN_DEF,
 113         Feature.ASYNC_KEYWORDS,
 114         Feature.FUTURE_ANNOTATIONS,
 115         Feature.ASSIGNMENT_EXPRESSIONS,
 116         Feature.RELAXED_DECORATORS,
 117         Feature.POS_ONLY_ARGUMENTS,
 118         Feature.UNPACKING_ON_FLOW,
 119         Feature.ANN_ASSIGN_EXTENDED_RHS,
 120         Feature.PATTERN_MATCHING,
 121     },
 122     TargetVersion.PY311: {
 123         Feature.F_STRINGS,
 124         Feature.NUMERIC_UNDERSCORES,
 125         Feature.TRAILING_COMMA_IN_CALL,
 126         Feature.TRAILING_COMMA_IN_DEF,
 127         Feature.ASYNC_KEYWORDS,
 128         Feature.FUTURE_ANNOTATIONS,
 129         Feature.ASSIGNMENT_EXPRESSIONS,
 130         Feature.RELAXED_DECORATORS,
 131         Feature.POS_ONLY_ARGUMENTS,
 132         Feature.UNPACKING_ON_FLOW,
 133         Feature.ANN_ASSIGN_EXTENDED_RHS,
 134         Feature.PATTERN_MATCHING,
 135         Feature.EXCEPT_STAR,
 136         Feature.VARIADIC_GENERICS,
 137     },
 138 }
 139
 140
 141 def supports_feature(target_versions: Set[TargetVersion], feature: Feature) -> bool:
 142     return all(feature in VERSION_TO_FEATURES[version] for version in target_versions)
 143
 144
 145 class Preview(Enum):
 146     """Individual preview style features."""
 147
 148     annotation_parens = auto()
 149     long_docstring_quotes_on_newline = auto()
 150     normalize_docstring_quotes_and_prefixes_properly = auto()
 151     one_element_subscript = auto()
 152     remove_block_trailing_newline = auto()
 153     remove_redundant_parens = auto()
 154     string_processing = auto()
 155
 156
 157 class Deprecated(UserWarning):
 158     """Visible deprecation warning."""
 159
 160
 161 @dataclass
 162 class Mode:
 163     target_versions: Set[TargetVersion] = field(default_factory=set)
 164     line_length: int = DEFAULT_LINE_LENGTH
 165     string_normalization: bool = True
 166     is_pyi: bool = False
 167     is_ipynb: bool = False
 168     magic_trailing_comma: bool = True
 169     experimental_string_processing: bool = False
 170     python_cell_magics: Set[str] = field(default_factory=set)
 171     preview: bool = False
 172
 173     def __post_init__(self) -> None:
 174         if self.experimental_string_processing:
 175             warn(
 176                 "`experimental string processing` has been included in `preview`"
 177                 " and deprecated. Use `preview` instead.",
 178                 Deprecated,
 179             )
 180
 181     def __contains__(self, feature: Preview) -> bool:
 182         """
 183         Provide `Preview.FEATURE in Mode` syntax that mirrors the ``preview`` flag.
 184
 185         The argument is not checked and features are not differentiated.
 186         They only exist to make development easier by clarifying intent.
 187         """
 188         if feature is Preview.string_processing:
 189             return self.preview or self.experimental_string_processing
 190         return self.preview
 191
 192     def get_cache_key(self) -> str:
 193         if self.target_versions:
 194             version_str = ",".join(
 195                 str(version.value)
 196                 for version in sorted(self.target_versions, key=attrgetter("value"))
 197             )
 198         else:
 199             version_str = "-"
 200         parts = [
 201             version_str,
 202             str(self.line_length),
 203             str(int(self.string_normalization)),
 204             str(int(self.is_pyi)),
 205             str(int(self.is_ipynb)),
 206             str(int(self.magic_trailing_comma)),
 207             str(int(self.experimental_string_processing)),
 208             str(int(self.preview)),
 209             sha256((",".join(sorted(self.python_cell_magics))).encode()).hexdigest(),
 210         ]
 211         return ".".join(parts)