Total Complexity | 146 |
Total Lines | 1302 |
Duplicated Lines | 2.3 % |
Coverage | 0% |
Changes | 0 |
Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like openscap_report.dataclasses.dataclasses often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
1 | # pylint: disable=too-many-lines |
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2 | import copy |
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3 | import inspect |
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4 | import keyword |
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5 | import re |
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6 | import sys |
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7 | import types |
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8 | |||
9 | __all__ = [ |
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10 | "dataclass", |
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11 | "field", |
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12 | "Field", |
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13 | "FrozenInstanceError", |
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14 | "InitVar", |
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15 | "MISSING", |
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16 | # Helper functions. |
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17 | "fields", |
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18 | "asdict", |
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19 | "astuple", |
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20 | "make_dataclass", |
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21 | "replace", |
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22 | "is_dataclass", |
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23 | ] |
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24 | |||
25 | # Conditions for adding methods. The boxes indicate what action the |
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26 | # dataclass decorator takes. For all of these tables, when I talk |
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27 | # about init=, repr=, eq=, order=, unsafe_hash=, or frozen=, I'm |
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28 | # referring to the arguments to the @dataclass decorator. When |
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29 | # checking if a dunder method already exists, I mean check for an |
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30 | # entry in the class's __dict__. I never check to see if an attribute |
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31 | # is defined in a base class. |
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32 | |||
33 | # Key: |
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34 | # +=========+=========================================+ |
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35 | # + Value | Meaning | |
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36 | # +=========+=========================================+ |
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37 | # | <blank> | No action: no method is added. | |
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38 | # +---------+-----------------------------------------+ |
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39 | # | add | Generated method is added. | |
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40 | # +---------+-----------------------------------------+ |
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41 | # | raise | TypeError is raised. | |
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42 | # +---------+-----------------------------------------+ |
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43 | # | None | Attribute is set to None. | |
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44 | # +=========+=========================================+ |
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45 | |||
46 | # __init__ |
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47 | # |
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48 | # +--- init= parameter |
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49 | # | |
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50 | # v | | | |
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51 | # | no | yes | <--- class has __init__ in __dict__? |
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52 | # +=======+=======+=======+ |
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53 | # | False | | | |
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54 | # +-------+-------+-------+ |
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55 | # | True | add | | <- the default |
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56 | # +=======+=======+=======+ |
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57 | |||
58 | # __repr__ |
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59 | # |
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60 | # +--- repr= parameter |
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61 | # | |
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62 | # v | | | |
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63 | # | no | yes | <--- class has __repr__ in __dict__? |
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64 | # +=======+=======+=======+ |
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65 | # | False | | | |
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66 | # +-------+-------+-------+ |
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67 | # | True | add | | <- the default |
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68 | # +=======+=======+=======+ |
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69 | |||
70 | |||
71 | # __setattr__ |
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72 | # __delattr__ |
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73 | # |
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74 | # +--- frozen= parameter |
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75 | # | |
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76 | # v | | | |
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77 | # | no | yes | <--- class has __setattr__ or __delattr__ in __dict__? |
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78 | # +=======+=======+=======+ |
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79 | # | False | | | <- the default |
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80 | # +-------+-------+-------+ |
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81 | # | True | add | raise | |
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82 | # +=======+=======+=======+ |
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83 | # Raise because not adding these methods would break the "frozen-ness" |
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84 | # of the class. |
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85 | |||
86 | # __eq__ |
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87 | # |
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88 | # +--- eq= parameter |
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89 | # | |
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90 | # v | | | |
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91 | # | no | yes | <--- class has __eq__ in __dict__? |
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92 | # +=======+=======+=======+ |
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93 | # | False | | | |
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94 | # +-------+-------+-------+ |
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95 | # | True | add | | <- the default |
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96 | # +=======+=======+=======+ |
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97 | |||
98 | # __lt__ |
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99 | # __le__ |
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100 | # __gt__ |
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101 | # __ge__ |
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102 | # |
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103 | # +--- order= parameter |
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104 | # | |
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105 | # v | | | |
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106 | # | no | yes | <--- class has any comparison method in __dict__? |
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107 | # +=======+=======+=======+ |
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108 | # | False | | | <- the default |
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109 | # +-------+-------+-------+ |
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110 | # | True | add | raise | |
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111 | # +=======+=======+=======+ |
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112 | # Raise because to allow this case would interfere with using |
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113 | # functools.total_ordering. |
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114 | |||
115 | # __hash__ |
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116 | |||
117 | # +------------------- unsafe_hash= parameter |
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118 | # | +----------- eq= parameter |
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119 | # | | +--- frozen= parameter |
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120 | # | | | |
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121 | # v v v | | | |
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122 | # | no | yes | <--- class has explicitly defined __hash__ |
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123 | # +=======+=======+=======+========+========+ |
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124 | # | False | False | False | | | No __eq__, use the base class __hash__ |
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125 | # +-------+-------+-------+--------+--------+ |
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126 | # | False | False | True | | | No __eq__, use the base class __hash__ |
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127 | # +-------+-------+-------+--------+--------+ |
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128 | # | False | True | False | None | | <-- the default, not hashable |
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129 | # +-------+-------+-------+--------+--------+ |
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130 | # | False | True | True | add | | Frozen, so hashable, allows override |
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131 | # +-------+-------+-------+--------+--------+ |
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132 | # | True | False | False | add | raise | Has no __eq__, but hashable |
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133 | # +-------+-------+-------+--------+--------+ |
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134 | # | True | False | True | add | raise | Has no __eq__, but hashable |
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135 | # +-------+-------+-------+--------+--------+ |
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136 | # | True | True | False | add | raise | Not frozen, but hashable |
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137 | # +-------+-------+-------+--------+--------+ |
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138 | # | True | True | True | add | raise | Frozen, so hashable |
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139 | # +=======+=======+=======+========+========+ |
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140 | # For boxes that are blank, __hash__ is untouched and therefore |
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141 | # inherited from the base class. If the base is object, then |
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142 | # id-based hashing is used. |
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143 | # |
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144 | # Note that a class may already have __hash__=None if it specified an |
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145 | # __eq__ method in the class body (not one that was created by |
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146 | # @dataclass). |
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147 | # |
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148 | # See _hash_action (below) for a coded version of this table. |
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149 | |||
150 | |||
151 | # Raised when an attempt is made to modify a frozen class. |
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152 | class FrozenInstanceError(AttributeError): |
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153 | pass |
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154 | |||
155 | |||
156 | # A sentinel object for default values to signal that a default |
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157 | # factory will be used. This is given a nice repr() which will appear |
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158 | # in the function signature of dataclasses' constructors. |
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159 | # pylint: disable=invalid-name |
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160 | class _HAS_DEFAULT_FACTORY_CLASS: |
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161 | def __repr__(self): |
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162 | return "<factory>" |
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163 | |||
164 | |||
165 | _HAS_DEFAULT_FACTORY = _HAS_DEFAULT_FACTORY_CLASS() |
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166 | |||
167 | |||
168 | # A sentinel object to detect if a parameter is supplied or not. Use |
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169 | # a class to give it a better repr. |
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170 | # pylint: disable=invalid-name |
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171 | class _MISSING_TYPE: |
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172 | pass |
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173 | |||
174 | |||
175 | MISSING = _MISSING_TYPE() |
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176 | |||
177 | # Since most per-field metadata will be unused, create an empty |
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178 | # read-only proxy that can be shared among all fields. |
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179 | _EMPTY_METADATA = types.MappingProxyType({}) |
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180 | |||
181 | |||
182 | # Markers for the various kinds of fields and pseudo-fields. |
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183 | # pylint: disable=invalid-name |
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184 | class _FIELD_BASE: |
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185 | def __init__(self, name): |
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186 | self.name = name |
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187 | |||
188 | def __repr__(self): |
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189 | return self.name |
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190 | |||
191 | |||
192 | _FIELD = _FIELD_BASE("_FIELD") |
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193 | _FIELD_CLASSVAR = _FIELD_BASE("_FIELD_CLASSVAR") |
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194 | _FIELD_INITVAR = _FIELD_BASE("_FIELD_INITVAR") |
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195 | |||
196 | # The name of an attribute on the class where we store the Field |
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197 | # objects. Also used to check if a class is a Data Class. |
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198 | _FIELDS = "__dataclass_fields__" |
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199 | |||
200 | # The name of an attribute on the class that stores the parameters to |
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201 | # @dataclass. |
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202 | _PARAMS = "__dataclass_params__" |
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203 | |||
204 | # The name of the function, that if it exists, is called at the end of |
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205 | # __init__. |
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206 | _POST_INIT_NAME = "__post_init__" |
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207 | |||
208 | # String regex that string annotations for ClassVar or InitVar must match. |
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209 | # Allows "identifier.identifier[" or "identifier[". |
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210 | # https://bugs.python.org/issue33453 for details. |
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211 | _MODULE_IDENTIFIER_RE = re.compile(r"^(?:\s*(\w+)\s*\.)?\s*(\w+)") |
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212 | |||
213 | |||
214 | class _InitVarMeta(type): |
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215 | def __getitem__(cls, params): |
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216 | return cls |
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217 | |||
218 | |||
219 | class InitVar(metaclass=_InitVarMeta): |
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220 | pass |
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221 | |||
222 | |||
223 | # Instances of Field are only ever created from within this module, |
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224 | # and only from the field() function, although Field instances are |
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225 | # exposed externally as (conceptually) read-only objects. |
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226 | # |
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227 | # name and type are filled in after the fact, not in __init__. |
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228 | # They're not known at the time this class is instantiated, but it's |
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229 | # convenient if they're available later. |
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230 | # |
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231 | # When cls._FIELDS is filled in with a list of Field objects, the name |
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232 | # and type fields will have been populated. |
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233 | # pylint: disable=too-many-instance-attributes |
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234 | class Field: |
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235 | __slots__ = ( |
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236 | "name", |
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237 | "type", |
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238 | "default", |
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239 | "default_factory", |
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240 | "repr", |
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241 | "hash", |
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242 | "init", |
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243 | "compare", |
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244 | "metadata", |
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245 | "_field_type", # Private: not to be used by user code. |
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246 | ) |
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247 | |||
248 | # pylint: disable=too-many-arguments |
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249 | # pylint: disable=redefined-builtin |
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250 | def __init__(self, default, default_factory, init, repr, hash, compare, metadata): |
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251 | self.name = None |
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252 | self.type = None |
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253 | self.default = default |
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254 | self.default_factory = default_factory |
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255 | self.init = init |
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256 | self.repr = repr |
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257 | self.hash = hash |
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258 | self.compare = compare |
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259 | self.metadata = ( |
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260 | _EMPTY_METADATA |
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261 | if metadata is None or len(metadata) == 0 |
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262 | else types.MappingProxyType(metadata) |
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263 | ) |
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264 | self._field_type = None |
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265 | |||
266 | def __repr__(self): |
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267 | return ( |
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268 | "Field(" |
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269 | f"name={self.name!r}," |
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270 | f"type={self.type!r}," |
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271 | f"default={self.default!r}," |
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272 | f"default_factory={self.default_factory!r}," |
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273 | f"init={self.init!r}," |
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274 | f"repr={self.repr!r}," |
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275 | f"hash={self.hash!r}," |
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276 | f"compare={self.compare!r}," |
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277 | f"metadata={self.metadata!r}," |
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278 | f"_field_type={self._field_type}" |
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279 | ")" |
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280 | ) |
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281 | |||
282 | # This is used to support the PEP 487 __set_name__ protocol in the |
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283 | # case where we're using a field that contains a descriptor as a |
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284 | # default value. For details on __set_name__, see |
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285 | # https://www.python.org/dev/peps/pep-0487/#implementation-details. |
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286 | # |
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287 | # Note that in _process_class, this Field object is overwritten |
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288 | # with the default value, so the end result is a descriptor that |
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289 | # had __set_name__ called on it at the right time. |
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290 | def __set_name__(self, owner, name): |
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291 | func = getattr(type(self.default), "__set_name__", None) |
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292 | if func: |
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293 | # There is a __set_name__ method on the descriptor, call |
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294 | # it. |
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295 | func(self.default, owner, name) |
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296 | |||
297 | |||
298 | class _DataclassParams: |
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299 | __slots__ = ( |
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300 | "init", |
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301 | "repr", |
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302 | "eq", |
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303 | "order", |
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304 | "unsafe_hash", |
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305 | "frozen", |
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306 | ) |
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307 | |||
308 | # pylint: disable=too-many-arguments |
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309 | # pylint: disable=redefined-builtin |
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310 | def __init__(self, init, repr, eq, order, unsafe_hash, frozen): |
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311 | self.init = init |
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312 | self.repr = repr |
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313 | self.eq = eq |
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314 | self.order = order |
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315 | self.unsafe_hash = unsafe_hash |
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316 | self.frozen = frozen |
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317 | |||
318 | def __repr__(self): |
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319 | return ( |
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320 | "_DataclassParams(" |
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321 | f"init={self.init!r}," |
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322 | f"repr={self.repr!r}," |
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323 | f"eq={self.eq!r}," |
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324 | f"order={self.order!r}," |
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325 | f"unsafe_hash={self.unsafe_hash!r}," |
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326 | f"frozen={self.frozen!r}" |
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327 | ")" |
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328 | ) |
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329 | |||
330 | |||
331 | # This function is used instead of exposing Field creation directly, |
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332 | # so that a type checker can be told (via overloads) that this is a |
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333 | # function whose type depends on its parameters. |
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334 | # pylint: disable=too-many-arguments |
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335 | # pylint: disable=redefined-builtin |
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336 | def field( |
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337 | *, |
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338 | default=MISSING, |
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339 | default_factory=MISSING, |
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340 | init=True, |
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341 | repr=True, |
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342 | hash=None, |
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343 | compare=True, |
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344 | metadata=None, |
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345 | ): |
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346 | """Return an object to identify dataclass fields. |
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347 | |||
348 | default is the default value of the field. default_factory is a |
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349 | 0-argument function called to initialize a field's value. If init |
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350 | is True, the field will be a parameter to the class's __init__() |
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351 | function. If repr is True, the field will be included in the |
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352 | object's repr(). If hash is True, the field will be included in |
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353 | the object's hash(). If compare is True, the field will be used |
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354 | in comparison functions. metadata, if specified, must be a |
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355 | mapping which is stored but not otherwise examined by dataclass. |
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356 | |||
357 | It is an error to specify both default and default_factory. |
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358 | """ |
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359 | |||
360 | if default is not MISSING and default_factory is not MISSING: |
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361 | raise ValueError("cannot specify both default and default_factory") |
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362 | return Field(default, default_factory, init, repr, hash, compare, metadata) |
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363 | |||
364 | |||
365 | # pylint: disable=redefined-outer-name |
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366 | def _tuple_str(obj_name, fields): |
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367 | # Return a string representing each field of obj_name as a tuple |
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368 | # member. So, if fields is ['x', 'y'] and obj_name is "self", |
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369 | # return "(self.x,self.y)". |
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370 | |||
371 | # Special case for the 0-tuple. |
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372 | if not fields: |
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373 | return "()" |
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374 | # Note the trailing comma, needed if this turns out to be a 1-tuple. |
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375 | return f'({",".join([f"{obj_name}.{f.name}" for f in fields])},)' |
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376 | |||
377 | |||
378 | def _create_fn(name, args, body, *, globals=None, locals=None, return_type=MISSING): |
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379 | # Note that we mutate locals when exec() is called. Caller |
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380 | # beware! The only callers are internal to this module, so no |
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381 | # worries about external callers. |
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382 | if locals is None: |
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383 | locals = {} |
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384 | return_annotation = "" |
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385 | if return_type is not MISSING: |
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386 | locals["_return_type"] = return_type |
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387 | return_annotation = "->_return_type" |
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388 | args = ",".join(args) |
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389 | body = "\n".join(f" {b}" for b in body) |
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390 | |||
391 | # Compute the text of the entire function. |
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392 | txt = f"def {name}({args}){return_annotation}:\n{body}" |
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393 | |||
394 | # pylint: disable=exec-used |
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395 | exec(txt, globals, locals) |
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396 | return locals[name] |
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397 | |||
398 | |||
399 | def _field_assign(frozen, name, value, self_name): |
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400 | # If we're a frozen class, then assign to our fields in __init__ |
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401 | # via object.__setattr__. Otherwise, just use a simple |
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402 | # assignment. |
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403 | # |
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404 | # self_name is what "self" is called in this function: don't |
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405 | # hard-code "self", since that might be a field name. |
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406 | if frozen: |
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407 | return f"object.__setattr__({self_name},{name!r},{value})" |
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408 | return f"{self_name}.{name}={value}" |
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409 | |||
410 | |||
411 | def _field_init(f, frozen, globals, self_name): |
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412 | # Return the text of the line in the body of __init__ that will |
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413 | # initialize this field. |
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414 | |||
415 | default_name = f"_dflt_{f.name}" |
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416 | if f.default_factory is not MISSING: |
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417 | if f.init: |
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418 | # This field has a default factory. If a parameter is |
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419 | # given, use it. If not, call the factory. |
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420 | globals[default_name] = f.default_factory |
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421 | value = ( |
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422 | f"{default_name}() " |
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423 | f"if {f.name} is _HAS_DEFAULT_FACTORY " |
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424 | f"else {f.name}" |
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425 | ) |
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426 | else: |
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427 | # This is a field that's not in the __init__ params, but |
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428 | # has a default factory function. It needs to be |
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429 | # initialized here by calling the factory function, |
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430 | # because there's no other way to initialize it. |
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431 | |||
432 | # For a field initialized with a default=defaultvalue, the |
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433 | # class dict just has the default value |
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434 | # (cls.fieldname=defaultvalue). But that won't work for a |
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435 | # default factory, the factory must be called in __init__ |
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436 | # and we must assign that to self.fieldname. We can't |
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437 | # fall back to the class dict's value, both because it's |
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438 | # not set, and because it might be different per-class |
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439 | # (which, after all, is why we have a factory function!). |
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440 | |||
441 | globals[default_name] = f.default_factory |
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442 | value = f"{default_name}()" |
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443 | else: |
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444 | # No default factory. |
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445 | if f.init: |
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446 | if f.default is MISSING: |
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447 | # There's no default, just do an assignment. |
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448 | value = f.name |
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449 | else: |
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450 | globals[default_name] = f.default |
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451 | value = f.name |
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452 | else: |
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453 | # This field does not need initialization. Signify that |
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454 | # to the caller by returning None. |
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455 | return None |
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456 | |||
457 | # Only test this now, so that we can create variables for the |
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458 | # default. However, return None to signify that we're not going |
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459 | # to actually do the assignment statement for InitVars. |
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460 | # pylint: disable=protected-access |
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461 | if f._field_type is _FIELD_INITVAR: |
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462 | return None |
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463 | |||
464 | # Now, actually generate the field assignment. |
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465 | return _field_assign(frozen, f.name, value, self_name) |
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466 | |||
467 | |||
468 | def _init_param(f): |
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469 | # Return the __init__ parameter string for this field. For |
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470 | # example, the equivalent of 'x:int=3' (except instead of 'int', |
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471 | # reference a variable set to int, and instead of '3', reference a |
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472 | # variable set to 3). |
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473 | default = None |
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474 | if f.default is MISSING and f.default_factory is MISSING: |
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475 | # There's no default, and no default_factory, just output the |
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476 | # variable name and type. |
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477 | default = "" |
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478 | elif f.default is not MISSING: |
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479 | # There's a default, this will be the name that's used to look |
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480 | # it up. |
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481 | default = f"=_dflt_{f.name}" |
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482 | elif f.default_factory is not MISSING: |
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483 | # There's a factory function. Set a marker. |
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484 | default = "=_HAS_DEFAULT_FACTORY" |
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485 | return f"{f.name}:_type_{f.name}{default}" |
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486 | |||
487 | |||
488 | def _init_fn(fields, frozen, has_post_init, self_name): |
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489 | # fields contains both real fields and InitVar pseudo-fields. |
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490 | |||
491 | # Make sure we don't have fields without defaults following fields |
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492 | # with defaults. This actually would be caught when exec-ing the |
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493 | # function source code, but catching it here gives a better error |
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494 | # message, and future-proofs us in case we build up the function |
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495 | # using ast. |
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496 | seen_default = False |
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497 | for f in fields: |
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498 | # Only consider fields in the __init__ call. |
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499 | if f.init: |
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500 | if not (f.default is MISSING and f.default_factory is MISSING): |
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501 | seen_default = True |
||
502 | elif seen_default: |
||
503 | raise TypeError( |
||
504 | f"non-default argument {f.name!r} " "follows default argument" |
||
505 | ) |
||
506 | |||
507 | globals = {"MISSING": MISSING, "_HAS_DEFAULT_FACTORY": _HAS_DEFAULT_FACTORY} |
||
508 | |||
509 | body_lines = [] |
||
510 | for f in fields: |
||
511 | line = _field_init(f, frozen, globals, self_name) |
||
512 | # line is None means that this field doesn't require |
||
513 | # initialization (it's a pseudo-field). Just skip it. |
||
514 | if line: |
||
515 | body_lines.append(line) |
||
516 | |||
517 | # Does this class have a post-init function? |
||
518 | if has_post_init: |
||
519 | # pylint: disable=protected-access |
||
520 | params_str = ",".join(f.name for f in fields if f._field_type is _FIELD_INITVAR) |
||
521 | body_lines.append(f"{self_name}.{_POST_INIT_NAME}({params_str})") |
||
522 | |||
523 | # If no body lines, use 'pass'. |
||
524 | if not body_lines: |
||
525 | body_lines = ["pass"] |
||
526 | |||
527 | locals = {f"_type_{f.name}": f.type for f in fields} |
||
528 | return _create_fn( |
||
529 | "__init__", |
||
530 | [self_name] + [_init_param(f) for f in fields if f.init], |
||
531 | body_lines, |
||
532 | locals=locals, |
||
533 | globals=globals, |
||
534 | return_type=None, |
||
535 | ) |
||
536 | |||
537 | |||
538 | def _repr_fn(fields): |
||
539 | return _create_fn( |
||
540 | "__repr__", |
||
541 | ("self",), |
||
542 | [ |
||
543 | 'return self.__class__.__qualname__ + f"(' |
||
544 | + ", ".join([f"{f.name}={{self.{f.name}!r}}" for f in fields]) # noqa: W503 |
||
545 | + ')"' # noqa: W503 |
||
546 | ], |
||
547 | ) |
||
548 | |||
549 | |||
550 | def _frozen_get_del_attr(cls, fields): |
||
551 | # pylint: disable=fixme |
||
552 | # XXX: globals is modified on the first call to _create_fn, then |
||
553 | # the modified version is used in the second call. Is this okay? |
||
554 | globals = {"cls": cls, "FrozenInstanceError": FrozenInstanceError} |
||
555 | if fields: |
||
556 | fields_str = "(" + ",".join(repr(f.name) for f in fields) + ",)" |
||
557 | else: |
||
558 | # Special case for the zero-length tuple. |
||
559 | fields_str = "()" |
||
560 | return ( |
||
561 | _create_fn( |
||
562 | "__setattr__", |
||
563 | ("self", "name", "value"), |
||
564 | ( |
||
565 | f"if type(self) is cls or name in {fields_str}:", |
||
566 | ' raise FrozenInstanceError(f"cannot assign to field {name!r}")', |
||
567 | "super(cls, self).__setattr__(name, value)", |
||
568 | ), |
||
569 | globals=globals, |
||
570 | ), |
||
571 | _create_fn( |
||
572 | "__delattr__", |
||
573 | ("self", "name"), |
||
574 | ( |
||
575 | f"if type(self) is cls or name in {fields_str}:", |
||
576 | ' raise FrozenInstanceError(f"cannot delete field {name!r}")', |
||
577 | "super(cls, self).__delattr__(name)", |
||
578 | ), |
||
579 | globals=globals, |
||
580 | ), |
||
581 | ) |
||
582 | |||
583 | |||
584 | def _cmp_fn(name, op, self_tuple, other_tuple): |
||
585 | # Create a comparison function. If the fields in the object are |
||
586 | # named 'x' and 'y', then self_tuple is the string |
||
587 | # '(self.x,self.y)' and other_tuple is the string |
||
588 | # '(other.x,other.y)'. |
||
589 | |||
590 | return _create_fn( |
||
591 | name, |
||
592 | ("self", "other"), |
||
593 | [ |
||
594 | "if other.__class__ is self.__class__:", |
||
595 | f" return {self_tuple}{op}{other_tuple}", |
||
596 | "return NotImplemented", |
||
597 | ], |
||
598 | ) |
||
599 | |||
600 | |||
601 | def _hash_fn(fields): |
||
602 | self_tuple = _tuple_str("self", fields) |
||
603 | return _create_fn("__hash__", ("self",), [f"return hash({self_tuple})"]) |
||
604 | |||
605 | |||
606 | def _is_classvar(a_type, typing): |
||
607 | # This test uses a typing internal class, but it's the best way to |
||
608 | # test if this is a ClassVar. |
||
609 | # pylint: disable=protected-access |
||
610 | # pylint: disable=unidiomatic-typecheck |
||
611 | return type(a_type) is typing._ClassVar |
||
612 | |||
613 | |||
614 | def _is_initvar(a_type, dataclasses): |
||
615 | # The module we're checking against is the module we're |
||
616 | # currently in (dataclasses.py). |
||
617 | return a_type is dataclasses.InitVar |
||
618 | |||
619 | |||
620 | def _is_type(annotation, cls, a_module, a_type, is_type_predicate): |
||
621 | # Given a type annotation string, does it refer to a_type in |
||
622 | # a_module? For example, when checking that annotation denotes a |
||
623 | # ClassVar, then a_module is typing, and a_type is |
||
624 | # typing.ClassVar. |
||
625 | |||
626 | # It's possible to look up a_module given a_type, but it involves |
||
627 | # looking in sys.modules (again!), and seems like a waste since |
||
628 | # the caller already knows a_module. |
||
629 | |||
630 | # - annotation is a string type annotation |
||
631 | # - cls is the class that this annotation was found in |
||
632 | # - a_module is the module we want to match |
||
633 | # - a_type is the type in that module we want to match |
||
634 | # - is_type_predicate is a function called with (obj, a_module) |
||
635 | # that determines if obj is of the desired type. |
||
636 | |||
637 | # Since this test does not do a local namespace lookup (and |
||
638 | # instead only a module (global) lookup), there are some things it |
||
639 | # gets wrong. |
||
640 | |||
641 | # With string annotations, cv0 will be detected as a ClassVar: |
||
642 | # CV = ClassVar |
||
643 | # @dataclass |
||
644 | # class C0: |
||
645 | # cv0: CV |
||
646 | |||
647 | # But in this example cv1 will not be detected as a ClassVar: |
||
648 | # @dataclass |
||
649 | # class C1: |
||
650 | # CV = ClassVar |
||
651 | # cv1: CV |
||
652 | |||
653 | # In C1, the code in this function (_is_type) will look up "CV" in |
||
654 | # the module and not find it, so it will not consider cv1 as a |
||
655 | # ClassVar. This is a fairly obscure corner case, and the best |
||
656 | # way to fix it would be to eval() the string "CV" with the |
||
657 | # correct global and local namespaces. However that would involve |
||
658 | # a eval() penalty for every single field of every dataclass |
||
659 | # that's defined. It was judged not worth it. |
||
660 | |||
661 | match = _MODULE_IDENTIFIER_RE.match(annotation) |
||
662 | if match: |
||
663 | ns = None |
||
664 | module_name = match.group(1) |
||
665 | if not module_name: |
||
666 | # No module name, assume the class's module did |
||
667 | # "from .dataclasses import InitVar". |
||
668 | ns = sys.modules.get(cls.__module__).__dict__ |
||
669 | else: |
||
670 | # Look up module_name in the class's module. |
||
671 | module = sys.modules.get(cls.__module__) |
||
672 | if module and module.__dict__.get(module_name) is a_module: |
||
673 | ns = sys.modules.get(a_type.__module__).__dict__ |
||
674 | if ns and is_type_predicate(ns.get(match.group(2)), a_module): |
||
675 | return True |
||
676 | return False |
||
677 | |||
678 | |||
679 | def _get_field(cls, a_name, a_type): |
||
680 | # Return a Field object for this field name and type. ClassVars |
||
681 | # and InitVars are also returned, but marked as such (see |
||
682 | # f._field_type). |
||
683 | |||
684 | # If the default value isn't derived from Field, then it's only a |
||
685 | # normal default value. Convert it to a Field(). |
||
686 | default = getattr(cls, a_name, MISSING) |
||
687 | if isinstance(default, Field): |
||
688 | f = default |
||
689 | else: |
||
690 | if isinstance(default, types.MemberDescriptorType): |
||
691 | # This is a field in __slots__, so it has no default value. |
||
692 | default = MISSING |
||
693 | f = field(default=default) |
||
694 | |||
695 | # Only at this point do we know the name and the type. Set them. |
||
696 | f.name = a_name |
||
697 | f.type = a_type |
||
698 | |||
699 | # Assume it's a normal field until proven otherwise. We're next |
||
700 | # going to decide if it's a ClassVar or InitVar, everything else |
||
701 | # is just a normal field. |
||
702 | # pylint: disable=protected-access |
||
703 | f._field_type = _FIELD |
||
704 | |||
705 | # In addition to checking for actual types here, also check for |
||
706 | # string annotations. get_type_hints() won't always work for us |
||
707 | # (see https://github.com/python/typing/issues/508 for example), |
||
708 | # plus it's expensive and would require an eval for every string |
||
709 | # annotation. So, make a best effort to see if this is a ClassVar |
||
710 | # or InitVar using regex's and checking that the thing referenced |
||
711 | # is actually of the correct type. |
||
712 | |||
713 | # For the complete discussion, see https://bugs.python.org/issue33453 |
||
714 | |||
715 | # If typing has not been imported, then it's impossible for any |
||
716 | # annotation to be a ClassVar. So, only look for ClassVar if |
||
717 | # typing has been imported by any module (not necessarily cls's |
||
718 | # module). |
||
719 | typing = sys.modules.get("typing") |
||
720 | if typing: |
||
721 | if _is_classvar(a_type, typing) or ( |
||
722 | isinstance(f.type, str) |
||
723 | and _is_type(f.type, cls, typing, typing.ClassVar, _is_classvar) # noqa: W503 |
||
724 | ): |
||
725 | # pylint: disable=protected-access |
||
726 | f._field_type = _FIELD_CLASSVAR |
||
727 | |||
728 | # If the type is InitVar, or if it's a matching string annotation, |
||
729 | # then it's an InitVar. |
||
730 | # pylint: disable=protected-access |
||
731 | if f._field_type is _FIELD: |
||
732 | # The module we're checking against is the module we're |
||
733 | # currently in (dataclasses.py). |
||
734 | dataclasses = sys.modules[__name__] |
||
735 | if _is_initvar(a_type, dataclasses) or ( |
||
736 | isinstance(f.type, str) |
||
737 | and _is_type(f.type, cls, dataclasses, dataclasses.InitVar, _is_initvar) # noqa: W503 |
||
738 | ): |
||
739 | # pylint: disable=protected-access |
||
740 | f._field_type = _FIELD_INITVAR |
||
741 | |||
742 | # Validations for individual fields. This is delayed until now, |
||
743 | # instead of in the Field() constructor, since only here do we |
||
744 | # know the field name, which allows for better error reporting. |
||
745 | |||
746 | # Special restrictions for ClassVar and InitVar. |
||
747 | # pylint: disable=protected-access |
||
748 | if f._field_type in (_FIELD_CLASSVAR, _FIELD_INITVAR): |
||
749 | if f.default_factory is not MISSING: |
||
750 | raise TypeError(f"field {f.name} cannot have a " "default factory") |
||
751 | # Should I check for other field settings? default_factory |
||
752 | # seems the most serious to check for. Maybe add others. For |
||
753 | # example, how about init=False (or really, |
||
754 | # init=<not-the-default-init-value>)? It makes no sense for |
||
755 | # ClassVar and InitVar to specify init=<anything>. |
||
756 | |||
757 | # For real fields, disallow mutable defaults for known types. |
||
758 | # pylint: disable=protected-access |
||
759 | if f._field_type is _FIELD and isinstance(f.default, (list, dict, set)): |
||
760 | raise ValueError( |
||
761 | f"mutable default {type(f.default)} for field " |
||
762 | f"{f.name} is not allowed: use default_factory" |
||
763 | ) |
||
764 | |||
765 | return f |
||
766 | |||
767 | |||
768 | def _set_new_attribute(cls, name, value): |
||
769 | # Never overwrites an existing attribute. Returns True if the |
||
770 | # attribute already exists. |
||
771 | if name in cls.__dict__: |
||
772 | return True |
||
773 | setattr(cls, name, value) |
||
774 | return False |
||
775 | |||
776 | |||
777 | # Decide if/how we're going to create a hash function. Key is |
||
778 | # (unsafe_hash, eq, frozen, does-hash-exist). Value is the action to |
||
779 | # take. The common case is to do nothing, so instead of providing a |
||
780 | # function that is a no-op, use None to signify that. |
||
781 | |||
782 | # pylint: disable=unused-argument |
||
783 | def _hash_set_none(cls, fields): |
||
784 | return None |
||
785 | |||
786 | |||
787 | # pylint: disable=unused-argument |
||
788 | def _hash_add(cls, fields): |
||
789 | flds = [f for f in fields if (f.compare if f.hash is None else f.hash)] |
||
790 | return _hash_fn(flds) |
||
791 | |||
792 | |||
793 | def _hash_exception(cls, fields): |
||
794 | # Raise an exception. |
||
795 | raise TypeError(f"Cannot overwrite attribute __hash__ " f"in class {cls.__name__}") |
||
796 | |||
797 | |||
798 | # |
||
799 | # +-------------------------------------- unsafe_hash? |
||
800 | # | +------------------------------- eq? |
||
801 | # | | +------------------------ frozen? |
||
802 | # | | | +---------------- has-explicit-hash? |
||
803 | # | | | | |
||
804 | # | | | | +------- action |
||
805 | # | | | | | |
||
806 | # v v v v v |
||
807 | _hash_action = { |
||
808 | (False, False, False, False): None, |
||
809 | (False, False, False, True): None, |
||
810 | (False, False, True, False): None, |
||
811 | (False, False, True, True): None, |
||
812 | (False, True, False, False): _hash_set_none, |
||
813 | (False, True, False, True): None, |
||
814 | (False, True, True, False): _hash_add, |
||
815 | (False, True, True, True): None, |
||
816 | (True, False, False, False): _hash_add, |
||
817 | (True, False, False, True): _hash_exception, |
||
818 | (True, False, True, False): _hash_add, |
||
819 | (True, False, True, True): _hash_exception, |
||
820 | (True, True, False, False): _hash_add, |
||
821 | (True, True, False, True): _hash_exception, |
||
822 | (True, True, True, False): _hash_add, |
||
823 | (True, True, True, True): _hash_exception, |
||
824 | } |
||
825 | # See https://bugs.python.org/issue32929#msg312829 for an if-statement |
||
826 | # version of this table. |
||
827 | |||
828 | |||
829 | # pylint: disable=too-many-locals |
||
830 | # pylint: disable=too-many-branches |
||
831 | # pylint: disable=too-many-statements |
||
832 | def _process_class(cls, init, repr, eq, order, unsafe_hash, frozen): # noqa: C901 |
||
833 | # Now that dicts retain insertion order, there's no reason to use |
||
834 | # an ordered dict. I am leveraging that ordering here, because |
||
835 | # derived class fields overwrite base class fields, but the order |
||
836 | # is defined by the base class, which is found first. |
||
837 | fields = {} |
||
838 | |||
839 | setattr(cls, _PARAMS, _DataclassParams(init, repr, eq, order, unsafe_hash, frozen)) |
||
840 | |||
841 | # Find our base classes in reverse MRO order, and exclude |
||
842 | # ourselves. In reversed order so that more derived classes |
||
843 | # override earlier field definitions in base classes. As long as |
||
844 | # we're iterating over them, see if any are frozen. |
||
845 | any_frozen_base = False |
||
846 | has_dataclass_bases = False |
||
847 | for b in cls.__mro__[-1:0:-1]: |
||
848 | # Only process classes that have been processed by our |
||
849 | # decorator. That is, they have a _FIELDS attribute. |
||
850 | base_fields = getattr(b, _FIELDS, None) |
||
851 | if base_fields: |
||
852 | has_dataclass_bases = True |
||
853 | for f in base_fields.values(): |
||
854 | fields[f.name] = f |
||
855 | if getattr(b, _PARAMS).frozen: |
||
856 | any_frozen_base = True |
||
857 | |||
858 | # Annotations that are defined in this class (not in base |
||
859 | # classes). If __annotations__ isn't present, then this class |
||
860 | # adds no new annotations. We use this to compute fields that are |
||
861 | # added by this class. |
||
862 | # |
||
863 | # Fields are found from cls_annotations, which is guaranteed to be |
||
864 | # ordered. Default values are from class attributes, if a field |
||
865 | # has a default. If the default value is a Field(), then it |
||
866 | # contains additional info beyond (and possibly including) the |
||
867 | # actual default value. Pseudo-fields ClassVars and InitVars are |
||
868 | # included, despite the fact that they're not real fields. That's |
||
869 | # dealt with later. |
||
870 | cls_annotations = cls.__dict__.get("__annotations__", {}) |
||
871 | |||
872 | # Now find fields in our class. While doing so, validate some |
||
873 | # things, and set the default values (as class attributes) where |
||
874 | # we can. |
||
875 | cls_fields = [_get_field(cls, name, type) for name, type in cls_annotations.items()] |
||
876 | for f in cls_fields: |
||
877 | fields[f.name] = f |
||
878 | |||
879 | # If the class attribute (which is the default value for this |
||
880 | # field) exists and is of type 'Field', replace it with the |
||
881 | # real default. This is so that normal class introspection |
||
882 | # sees a real default value, not a Field. |
||
883 | if isinstance(getattr(cls, f.name, None), Field): |
||
884 | if f.default is MISSING: |
||
885 | # If there's no default, delete the class attribute. |
||
886 | # This happens if we specify field(repr=False), for |
||
887 | # example (that is, we specified a field object, but |
||
888 | # no default value). Also if we're using a default |
||
889 | # factory. The class attribute should not be set at |
||
890 | # all in the post-processed class. |
||
891 | delattr(cls, f.name) |
||
892 | else: |
||
893 | setattr(cls, f.name, f.default) |
||
894 | |||
895 | # Do we have any Field members that don't also have annotations? |
||
896 | for name, value in cls.__dict__.items(): |
||
897 | if isinstance(value, Field) and name not in cls_annotations: |
||
898 | raise TypeError(f"{name!r} is a field but has no type annotation") |
||
899 | |||
900 | # Check rules that apply if we are derived from any dataclasses. |
||
901 | if has_dataclass_bases: |
||
902 | # Raise an exception if any of our bases are frozen, but we're not. |
||
903 | if any_frozen_base and not frozen: |
||
904 | raise TypeError("cannot inherit non-frozen dataclass from a frozen one") |
||
905 | |||
906 | # Raise an exception if we're frozen, but none of our bases are. |
||
907 | if not any_frozen_base and frozen: |
||
908 | raise TypeError("cannot inherit frozen dataclass from a non-frozen one") |
||
909 | |||
910 | # Remember all of the fields on our class (including bases). This |
||
911 | # also marks this class as being a dataclass. |
||
912 | setattr(cls, _FIELDS, fields) |
||
913 | |||
914 | # Was this class defined with an explicit __hash__? Note that if |
||
915 | # __eq__ is defined in this class, then python will automatically |
||
916 | # set __hash__ to None. This is a heuristic, as it's possible |
||
917 | # that such a __hash__ == None was not auto-generated, but it |
||
918 | # close enough. |
||
919 | class_hash = cls.__dict__.get("__hash__", MISSING) |
||
920 | has_explicit_hash = not ( |
||
921 | class_hash is MISSING or (class_hash is None and "__eq__" in cls.__dict__) |
||
922 | ) |
||
923 | |||
924 | # If we're generating ordering methods, we must be generating the |
||
925 | # eq methods. |
||
926 | if order and not eq: |
||
927 | raise ValueError("eq must be true if order is true") |
||
928 | |||
929 | if init: |
||
930 | # Does this class have a post-init function? |
||
931 | has_post_init = hasattr(cls, _POST_INIT_NAME) |
||
932 | |||
933 | # Include InitVars and regular fields (so, not ClassVars). |
||
934 | # pylint: disable=protected-access |
||
935 | flds = [f for f in fields.values() if f._field_type in (_FIELD, _FIELD_INITVAR)] |
||
936 | _set_new_attribute( |
||
937 | cls, |
||
938 | "__init__", |
||
939 | _init_fn( |
||
940 | flds, |
||
941 | frozen, |
||
942 | has_post_init, |
||
943 | # The name to use for the "self" |
||
944 | # param in __init__. Use "self" |
||
945 | # if possible. |
||
946 | "__dataclass_self__" if "self" in fields else "self", |
||
947 | ), |
||
948 | ) |
||
949 | |||
950 | # Get the fields as a list, and include only real fields. This is |
||
951 | # used in all of the following methods. |
||
952 | # pylint: disable=protected-access |
||
953 | field_list = [f for f in fields.values() if f._field_type is _FIELD] |
||
954 | |||
955 | if repr: |
||
956 | flds = [f for f in field_list if f.repr] |
||
957 | _set_new_attribute(cls, "__repr__", _repr_fn(flds)) |
||
958 | |||
959 | if eq: |
||
960 | # Create _eq__ method. There's no need for a __ne__ method, |
||
961 | # since python will call __eq__ and negate it. |
||
962 | flds = [f for f in field_list if f.compare] |
||
963 | self_tuple = _tuple_str("self", flds) |
||
964 | other_tuple = _tuple_str("other", flds) |
||
965 | _set_new_attribute( |
||
966 | cls, "__eq__", _cmp_fn("__eq__", "==", self_tuple, other_tuple) |
||
967 | ) |
||
968 | |||
969 | if order: |
||
970 | # Create and set the ordering methods. |
||
971 | flds = [f for f in field_list if f.compare] |
||
972 | self_tuple = _tuple_str("self", flds) |
||
973 | other_tuple = _tuple_str("other", flds) |
||
974 | for name, op in [ |
||
975 | ("__lt__", "<"), |
||
976 | ("__le__", "<="), |
||
977 | ("__gt__", ">"), |
||
978 | ("__ge__", ">="), |
||
979 | ]: |
||
980 | if _set_new_attribute( |
||
981 | cls, name, _cmp_fn(name, op, self_tuple, other_tuple) |
||
982 | ): |
||
983 | raise TypeError( |
||
984 | f"Cannot overwrite attribute {name} " |
||
985 | f"in class {cls.__name__}. Consider using " |
||
986 | "functools.total_ordering" |
||
987 | ) |
||
988 | |||
989 | if frozen: |
||
990 | for fn in _frozen_get_del_attr(cls, field_list): |
||
991 | if _set_new_attribute(cls, fn.__name__, fn): |
||
992 | raise TypeError( |
||
993 | f"Cannot overwrite attribute {fn.__name__} " |
||
994 | f"in class {cls.__name__}" |
||
995 | ) |
||
996 | |||
997 | # Decide if/how we're going to create a hash function. |
||
998 | hash_action = _hash_action[ |
||
999 | bool(unsafe_hash), bool(eq), bool(frozen), has_explicit_hash |
||
1000 | ] |
||
1001 | if hash_action: |
||
1002 | # No need to call _set_new_attribute here, since by the time |
||
1003 | # we're here the overwriting is unconditional. |
||
1004 | cls.__hash__ = hash_action(cls, field_list) |
||
1005 | |||
1006 | if not getattr(cls, "__doc__"): |
||
1007 | # Create a class doc-string. |
||
1008 | cls.__doc__ = cls.__name__ + str(inspect.signature(cls)).replace(" -> None", "") |
||
1009 | |||
1010 | return cls |
||
1011 | |||
1012 | |||
1013 | # _cls should never be specified by keyword, so start it with an |
||
1014 | # underscore. The presence of _cls is used to detect if this |
||
1015 | # decorator is being called with parameters or not. |
||
1016 | def dataclass( |
||
1017 | _cls=None, |
||
1018 | *, |
||
1019 | init=True, |
||
1020 | repr=True, |
||
1021 | eq=True, |
||
1022 | order=False, |
||
1023 | unsafe_hash=False, |
||
1024 | frozen=False, |
||
1025 | ): |
||
1026 | """Returns the same class as was passed in, with dunder methods |
||
1027 | added based on the fields defined in the class. |
||
1028 | |||
1029 | Examines PEP 526 __annotations__ to determine fields. |
||
1030 | |||
1031 | If init is true, an __init__() method is added to the class. If |
||
1032 | repr is true, a __repr__() method is added. If order is true, rich |
||
1033 | comparison dunder methods are added. If unsafe_hash is true, a |
||
1034 | __hash__() method function is added. If frozen is true, fields may |
||
1035 | not be assigned to after instance creation. |
||
1036 | """ |
||
1037 | |||
1038 | def wrap(cls): |
||
1039 | return _process_class(cls, init, repr, eq, order, unsafe_hash, frozen) |
||
1040 | |||
1041 | # See if we're being called as @dataclass or @dataclass(). |
||
1042 | if _cls is None: |
||
1043 | # We're called with parens. |
||
1044 | return wrap |
||
1045 | |||
1046 | # We're called as @dataclass without parens. |
||
1047 | return wrap(_cls) |
||
1048 | |||
1049 | |||
1050 | def fields(class_or_instance): |
||
1051 | """Return a tuple describing the fields of this dataclass. |
||
1052 | |||
1053 | Accepts a dataclass or an instance of one. Tuple elements are of |
||
1054 | type Field. |
||
1055 | """ |
||
1056 | |||
1057 | # Might it be worth caching this, per class? |
||
1058 | try: |
||
1059 | fields = getattr(class_or_instance, _FIELDS) |
||
1060 | except AttributeError: |
||
1061 | # pylint: disable=raise-missing-from |
||
1062 | raise TypeError("must be called with a dataclass type or instance") |
||
1063 | |||
1064 | # Exclude pseudo-fields. Note that fields is sorted by insertion |
||
1065 | # order, so the order of the tuple is as the fields were defined. |
||
1066 | # pylint: disable=protected-access |
||
1067 | return tuple(f for f in fields.values() if f._field_type is _FIELD) |
||
1068 | |||
1069 | |||
1070 | def _is_dataclass_instance(obj): |
||
1071 | """Returns True if obj is an instance of a dataclass.""" |
||
1072 | return not isinstance(obj, type) and hasattr(obj, _FIELDS) |
||
1073 | |||
1074 | |||
1075 | def is_dataclass(obj): |
||
1076 | """Returns True if obj is a dataclass or an instance of a |
||
1077 | dataclass.""" |
||
1078 | return hasattr(obj, _FIELDS) |
||
1079 | |||
1080 | |||
1081 | def asdict(obj, *, dict_factory=dict): |
||
1082 | """Return the fields of a dataclass instance as a new dictionary mapping |
||
1083 | field names to field values. |
||
1084 | |||
1085 | Example usage: |
||
1086 | |||
1087 | @dataclass |
||
1088 | class C: |
||
1089 | x: int |
||
1090 | y: int |
||
1091 | |||
1092 | c = C(1, 2) |
||
1093 | assert asdict(c) == {'x': 1, 'y': 2} |
||
1094 | |||
1095 | If given, 'dict_factory' will be used instead of built-in dict. |
||
1096 | The function applies recursively to field values that are |
||
1097 | dataclass instances. This will also look into built-in containers: |
||
1098 | tuples, lists, and dicts. |
||
1099 | """ |
||
1100 | if not _is_dataclass_instance(obj): |
||
1101 | raise TypeError("asdict() should be called on dataclass instances") |
||
1102 | return _asdict_inner(obj, dict_factory) |
||
1103 | |||
1104 | |||
1105 | View Code Duplication | def _asdict_inner(obj, dict_factory): |
|
|
|||
1106 | if _is_dataclass_instance(obj): |
||
1107 | result = [] |
||
1108 | for f in fields(obj): |
||
1109 | value = _asdict_inner(getattr(obj, f.name), dict_factory) |
||
1110 | result.append((f.name, value)) |
||
1111 | return dict_factory(result) |
||
1112 | if isinstance(obj, (list, tuple)): |
||
1113 | return type(obj)(_asdict_inner(v, dict_factory) for v in obj) |
||
1114 | if isinstance(obj, dict): |
||
1115 | return type(obj)( |
||
1116 | (_asdict_inner(k, dict_factory), _asdict_inner(v, dict_factory)) |
||
1117 | for k, v in obj.items() |
||
1118 | ) |
||
1119 | return copy.deepcopy(obj) |
||
1120 | |||
1121 | |||
1122 | def astuple(obj, *, tuple_factory=tuple): |
||
1123 | """Return the fields of a dataclass instance as a new tuple of field values. |
||
1124 | |||
1125 | Example usage:: |
||
1126 | |||
1127 | @dataclass |
||
1128 | class C: |
||
1129 | x: int |
||
1130 | y: int |
||
1131 | |||
1132 | c = C(1, 2) |
||
1133 | assert astuple(c) == (1, 2) |
||
1134 | |||
1135 | If given, 'tuple_factory' will be used instead of built-in tuple. |
||
1136 | The function applies recursively to field values that are |
||
1137 | dataclass instances. This will also look into built-in containers: |
||
1138 | tuples, lists, and dicts. |
||
1139 | """ |
||
1140 | |||
1141 | if not _is_dataclass_instance(obj): |
||
1142 | raise TypeError("astuple() should be called on dataclass instances") |
||
1143 | return _astuple_inner(obj, tuple_factory) |
||
1144 | |||
1145 | |||
1146 | View Code Duplication | def _astuple_inner(obj, tuple_factory): |
|
1147 | if _is_dataclass_instance(obj): |
||
1148 | result = [] |
||
1149 | for f in fields(obj): |
||
1150 | value = _astuple_inner(getattr(obj, f.name), tuple_factory) |
||
1151 | result.append(value) |
||
1152 | return tuple_factory(result) |
||
1153 | if isinstance(obj, (list, tuple)): |
||
1154 | return type(obj)(_astuple_inner(v, tuple_factory) for v in obj) |
||
1155 | if isinstance(obj, dict): |
||
1156 | return type(obj)( |
||
1157 | (_astuple_inner(k, tuple_factory), _astuple_inner(v, tuple_factory)) |
||
1158 | for k, v in obj.items() |
||
1159 | ) |
||
1160 | return copy.deepcopy(obj) |
||
1161 | |||
1162 | |||
1163 | def make_dataclass( |
||
1164 | cls_name, |
||
1165 | fields, |
||
1166 | *, |
||
1167 | bases=(), |
||
1168 | namespace=None, |
||
1169 | init=True, |
||
1170 | repr=True, |
||
1171 | eq=True, |
||
1172 | order=False, |
||
1173 | unsafe_hash=False, |
||
1174 | frozen=False, |
||
1175 | ): |
||
1176 | """Return a new dynamically created dataclass. |
||
1177 | |||
1178 | The dataclass name will be 'cls_name'. 'fields' is an iterable |
||
1179 | of either (name), (name, type) or (name, type, Field) objects. If type is |
||
1180 | omitted, use the string 'typing.Any'. Field objects are created by |
||
1181 | the equivalent of calling 'field(name, type [, Field-info])'. |
||
1182 | |||
1183 | C = make_dataclass('C', ['x', ('y', int), ('z', int, field(init=False))], bases=(Base,)) |
||
1184 | |||
1185 | is equivalent to: |
||
1186 | |||
1187 | @dataclass |
||
1188 | class C(Base): |
||
1189 | x: 'typing.Any' |
||
1190 | y: int |
||
1191 | z: int = field(init=False) |
||
1192 | |||
1193 | For the bases and namespace parameters, see the builtin type() function. |
||
1194 | |||
1195 | The parameters init, repr, eq, order, unsafe_hash, and frozen are passed to |
||
1196 | dataclass(). |
||
1197 | """ |
||
1198 | |||
1199 | if namespace is None: |
||
1200 | namespace = {} |
||
1201 | else: |
||
1202 | # Copy namespace since we're going to mutate it. |
||
1203 | namespace = namespace.copy() |
||
1204 | |||
1205 | # While we're looking through the field names, validate that they |
||
1206 | # are identifiers, are not keywords, and not duplicates. |
||
1207 | seen = set() |
||
1208 | anns = {} |
||
1209 | for item in fields: |
||
1210 | if isinstance(item, str): |
||
1211 | name = item |
||
1212 | tp = "typing.Any" |
||
1213 | elif len(item) == 2: |
||
1214 | ( |
||
1215 | name, |
||
1216 | tp, |
||
1217 | ) = item |
||
1218 | elif len(item) == 3: |
||
1219 | name, tp, spec = item |
||
1220 | namespace[name] = spec |
||
1221 | else: |
||
1222 | raise TypeError(f"Invalid field: {item!r}") |
||
1223 | |||
1224 | if not isinstance(name, str) or not name.isidentifier(): |
||
1225 | raise TypeError(f"Field names must be valid identifiers: {name!r}") |
||
1226 | if keyword.iskeyword(name): |
||
1227 | raise TypeError(f"Field names must not be keywords: {name!r}") |
||
1228 | if name in seen: |
||
1229 | raise TypeError(f"Field name duplicated: {name!r}") |
||
1230 | |||
1231 | seen.add(name) |
||
1232 | anns[name] = tp |
||
1233 | |||
1234 | namespace["__annotations__"] = anns |
||
1235 | # We use `types.new_class()` instead of simply `type()` to allow dynamic creation |
||
1236 | # of generic dataclassses. |
||
1237 | cls = types.new_class(cls_name, bases, {}, lambda ns: ns.update(namespace)) |
||
1238 | return dataclass( |
||
1239 | cls, |
||
1240 | init=init, |
||
1241 | repr=repr, |
||
1242 | eq=eq, |
||
1243 | order=order, |
||
1244 | unsafe_hash=unsafe_hash, |
||
1245 | frozen=frozen, |
||
1246 | ) |
||
1247 | |||
1248 | |||
1249 | def replace(obj, **changes): |
||
1250 | """Return a new object replacing specified fields with new values. |
||
1251 | |||
1252 | This is especially useful for frozen classes. Example usage: |
||
1253 | |||
1254 | @dataclass(frozen=True) |
||
1255 | class C: |
||
1256 | x: int |
||
1257 | y: int |
||
1258 | |||
1259 | c = C(1, 2) |
||
1260 | c1 = replace(c, x=3) |
||
1261 | assert c1.x == 3 and c1.y == 2 |
||
1262 | """ |
||
1263 | |||
1264 | # We're going to mutate 'changes', but that's okay because it's a |
||
1265 | # new dict, even if called with 'replace(obj, **my_changes)'. |
||
1266 | |||
1267 | if not _is_dataclass_instance(obj): |
||
1268 | raise TypeError("replace() should be called on dataclass instances") |
||
1269 | |||
1270 | # It's an error to have init=False fields in 'changes'. |
||
1271 | # If a field is not in 'changes', read its value from the provided obj. |
||
1272 | for f in getattr(obj, _FIELDS).values(): |
||
1273 | # Only consider normal fields or InitVars. |
||
1274 | # pylint: disable=protected-access |
||
1275 | if f._field_type is _FIELD_CLASSVAR: |
||
1276 | continue |
||
1277 | |||
1278 | if not f.init: |
||
1279 | # Error if this field is specified in changes. |
||
1280 | if f.name in changes: |
||
1281 | raise ValueError( |
||
1282 | f"field {f.name} is declared with " |
||
1283 | "init=False, it cannot be specified with " |
||
1284 | "replace()" |
||
1285 | ) |
||
1286 | continue |
||
1287 | |||
1288 | if f.name not in changes: |
||
1289 | # pylint: disable=protected-access |
||
1290 | if f._field_type is _FIELD_INITVAR: |
||
1291 | raise ValueError( |
||
1292 | f"InitVar {f.name!r} " "must be specified with replace()" |
||
1293 | ) |
||
1294 | changes[f.name] = getattr(obj, f.name) |
||
1295 | |||
1296 | # Create the new object, which calls __init__() and |
||
1297 | # __post_init__() (if defined), using all of the init fields we've |
||
1298 | # added and/or left in 'changes'. If there are values supplied in |
||
1299 | # changes that aren't fields, this will correctly raise a |
||
1300 | # TypeError. |
||
1301 | return obj.__class__(**changes) |
||
1302 |