fix(segments): Support NoneType. (#6581)

api/core/app/segments/__init__.py

 from .segment_group import SegmentGroup
-from .segments import Segment
+from .segments import NoneSegment, Segment
 from .types import SegmentType
 from .variables import (
     ArrayVariable,
     FileVariable,
     FloatVariable,
     IntegerVariable,
+    NoneVariable,
     ObjectVariable,
     SecretVariable,
     StringVariable,
     'Variable',
     'SegmentType',
     'SegmentGroup',
-    'Segment'
+    'Segment',
+    'NoneSegment',
+    'NoneVariable',
 ]

api/core/app/segments/factory.py

     FileVariable,
     FloatVariable,
     IntegerVariable,
+    NoneVariable,
     ObjectVariable,
     SecretVariable,
     StringVariable,
 
 
 def build_anonymous_variable(value: Any, /) -> Variable:
+    if value is None:
+        return NoneVariable(name='anonymous')
     if isinstance(value, str):
         return StringVariable(name='anonymous', value=value)
     if isinstance(value, int):

api/core/app/segments/segments.py

         return self.value
 
 
+class NoneSegment(Segment):
+    value_type: SegmentType = SegmentType.NONE
+    value: None = None
+
+    @property
+    def text(self) -> str:
+        return 'null'
+
+    @property
+    def log(self) -> str:
+        return 'null'
+
+    @property
+    def markdown(self) -> str:
+        return 'null'
+
+
 class StringSegment(Segment):
     value_type: SegmentType = SegmentType.STRING
     value: str

api/core/app/segments/types.py

     ARRAY_STRING = 'array[string]'
     ARRAY_NUMBER = 'array[number]'
     ARRAY_OBJECT = 'array[object]'
-    ARRAY_FILE = 'array[file]'
+    ARRAY_FILE = 'array[file]'
+    NONE = 'none'

api/core/app/segments/variables.py

     @property
     def log(self) -> str:
         return encrypter.obfuscated_token(self.value)
+
+
+class NoneVariable(Variable):
+    value_type: SegmentType = SegmentType.NONE
+    value: None = None

api/tests/unit_tests/app/test_variables.py

 from pydantic import ValidationError
 
 from core.app.segments import (
+    ArrayVariable,
     FloatVariable,
     IntegerVariable,
+    NoneVariable,
+    ObjectVariable,
     SecretVariable,
     SegmentType,
     StringVariable,
     factory,
 )
-from core.app.segments.variables import ArrayVariable, ObjectVariable
 
 
 def test_string_variable():
     assert var.to_object() == 3.14
     var = SecretVariable(name='secret', value='secret_value')
     assert var.to_object() == 'secret_value'
+
+
+def test_build_a_object_variable_with_none_value():
+    var = factory.build_anonymous_variable(
+        {
+            'key1': None,
+        }
+    )
+    assert isinstance(var, ObjectVariable)
+    assert isinstance(var.value['key1'], NoneVariable)