Support init=False for dataclass

jedi/inference/value/klass.py

@@ -49,7 +49,7 @@ from jedi.inference.arguments import unpack_arglist, ValuesArguments
 from jedi.inference.base_value import ValueSet, iterator_to_value_set, \
     NO_VALUES, ValueWrapper
 from jedi.inference.context import ClassContext
-from jedi.inference.value.function import FunctionAndClassBase
+from jedi.inference.value.function import FunctionAndClassBase, OverloadedFunctionValue
 from jedi.inference.value.decorator import Decoratee
 from jedi.inference.gradual.generics import LazyGenericManager, TupleGenericManager
 from jedi.plugins import plugin_manager
@@ -433,6 +433,40 @@ class DataclassSignature(AbstractSignature):
         return self._param_names
 
 
+class DataclassDecorator(OverloadedFunctionValue):
+    def __init__(self, function, overloaded_functions, arguments):
+        """
+        Args:
+            arguments: The parameters to the dataclass function decorator.
+        """
+        super().__init__(function, overloaded_functions)
+        self.arguments = arguments
+
+    @property
+    def has_dataclass_init_false(self) -> bool:
+        """
+        Returns:
+            bool: True if dataclass(init=False)
+        """
+        if not self.arguments.argument_node:
+            return False
+
+        arg_nodes = (
+            self.arguments.argument_node.children
+            if self.arguments.argument_node.type == "arglist"
+            else [self.arguments.argument_node]
+        )
+        for arg_node in arg_nodes:
+            if (
+                arg_node.type == "argument"
+                and arg_node.children[0].value == "init"
+                and arg_node.children[2].value == "False"
+            ):
+                return True
+
+        return False
+
+
 class DataclassWrapper(ValueWrapper, ClassMixin):
     def get_signatures(self):
         param_names = []

jedi/plugins/stdlib.py

@@ -24,7 +24,7 @@ from jedi.inference.value.instance import \
 from jedi.inference.base_value import ContextualizedNode, \
     NO_VALUES, ValueSet, ValueWrapper, LazyValueWrapper
 from jedi.inference.value import ClassValue, ModuleValue
-from jedi.inference.value.klass import DataclassWrapper
+from jedi.inference.value.klass import DataclassWrapper, DataclassDecorator
 from jedi.inference.value.function import FunctionMixin
 from jedi.inference.value import iterable
 from jedi.inference.lazy_value import LazyTreeValue, LazyKnownValue, \
@@ -590,11 +590,37 @@ def _random_choice(sequences):
 
 
 def _dataclass(value, arguments, callback):
+    """
+    dataclass decorator can be called 2 times with different arguments. One to
+    customize it dataclass(eq=True) and another one with the class to
+    transform.
+    """
     for c in _follow_param(value.inference_state, arguments, 0):
         if c.is_class():
-            return ValueSet([DataclassWrapper(c)])
+            # Decorate the class
+            dataclass_init = (
+                # Customized decorator
+                not value.has_dataclass_init_false
+                if isinstance(value, DataclassDecorator)
+                # Bare dataclass decorator
+                else True
+            )
+
+            if dataclass_init:
+                return ValueSet([DataclassWrapper(c)])
+            else:
+                return ValueSet([c])
         else:
-            return ValueSet([value])
+            # Decorator customization
+            return ValueSet(
+                [
+                    DataclassDecorator(
+                        value._wrapped_value,
+                        value._overloaded_functions,
+                        arguments=arguments,
+                    )
+                ]
+            )
     return NO_VALUES
 
 

test/test_inference/test_signature.py

@@ -350,11 +350,17 @@ def test_wraps_signature(Script, code, signature):
         [
             dedent(
                 """
-            @dataclass_transform(init=False)
+            @dataclass(init=False)
-            class Y():
+            class X:"""
-                y: int
+            ),
-                z = 5
+            [],
-            class X(Y):"""
+            False,
+        ],
+        [
+            dedent(
+                """
+            @dataclass(eq=True, init=False)
+            class X:"""
             ),
             [],
             False,
@@ -363,11 +369,8 @@ def test_wraps_signature(Script, code, signature):
         [
             dedent(
                 """
-        @dataclass_transform()
+        @dataclass()
-        class Y():
+        class X:
-            y: int
-            z = 5
-        class X(Y):
             def __init__(self, toto: str):
                 pass
             """
@@ -382,6 +385,7 @@ def test_wraps_signature(Script, code, signature):
         "subclass_transformed",
         "both_transformed",
         "init_false",
+        "init_false_multiple",
         "custom_init",
     ],
 )
@@ -418,7 +422,7 @@ def test_dataclass_signature(
         quantity, = sig.params[-1].infer()
         assert quantity.name == 'int'
         price, = sig.params[-2].infer()
-        assert price.name == 'float'
+        assert price.name == 'object'
 
 
 dataclass_transform_cases = [