Operator called by another operator does not trigger Adjust Last Operation panel

Question

I have an Operator defined as ImportImageOperator which calls another operator TraceAlphaOperator but it does not trigger showing the Adjust Last Operation panel for the latter operator. But if I directly call TraceAlphaOperator then it shows the panel. But why not when it is invoked by another operator?

I tried calling bpy.ops.object.trace_alpha(param) from the ImportImageOperator and testing it with both parameters EXEC_DEFAULT and INVOKE_DEFAULT, but nothing works. Initially I had everything in one operator but that did not seem to work due to the import dialog that was in the way. So I decided to split the operation into those two aforementioned operators. This is the script:

import bpy

class TraceAlphaOperator(bpy.types.Operator):
    bl_idname = "object.trace_alpha"
    bl_label = "Trace alpha"
    bl_options = {'REGISTER', 'UNDO'} # 'INTERNAL'}

    threshold: bpy.props.FloatProperty(
        name="Threshold",
        default=1.0,
    )

    def execute(self, context):
        print("Execute TraceAlphaOperator")
        # do stuff like tracing the alpha
        return {'FINISHED'}

class ImportImageOperator(bpy.types.Operator):
    bl_idname = "object.import_image_and_trace"
    bl_label = "Import image and trace alpha"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        print("Execute ImportImageOperator")
        # do stuff like save loaded image and further processing ...
        result = bpy.ops.object.trace_alpha('INVOKE_DEFAULT')
        return result

    def invoke(self, context, event):
        context.window_manager.fileselect_add(self)
        return {'RUNNING_MODAL'}

def register():
    bpy.utils.register_class(ImportImageOperator)
    bpy.utils.register_class(TraceAlphaOperator)

def unregister():
    bpy.utils.unregister_class(ImportImageOperator)
    bpy.utils.unregister_class(TraceAlphaOperator)

if __name__ == "__main__":
    register()

The only workaround I know is to have two separate buttons for the two operators. First, I click one button to invoke ImportImageOperator to load the image, and then I click another button to invoke TraceAlphaOperator to perform the alpha tracing, which also displays the Adjust Last Operation panel. However, I would prefer pressing only one button to load and trace the alpha. Is this not possible?

Answer 1

Apparently the last adjust panel can't seem to be called from a script

import bpy

class SimpleOperator(bpy.types.Operator):
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"
    bl_options = {"REGISTER", "UNDO", "BLOCKING"}

    test_float: bpy.props.FloatProperty()

    def execute(self, context):
        return {'FINISHED'}


def register():
    bpy.utils.register_class(SimpleOperator)

#def unregister():

if __name__ == "__main__":
    register()

    # test call
    a = next(e for e in bpy.context.screen.areas if e.type == "VIEW_3D")
    r = next(e for e in a.regions if e.type == "WINDOW")
    with bpy.context.temp_override(area=a, region=r):
        bpy.ops.object.simple_operator("INVOKE_DEFAULT")
        # bpy.ops.object.simple_operator("INVOKE_REGION_WIN")
        # bpy.ops.object.simple_operator("INVOKE_REGION_CHANNELS")
        # bpy.ops.object.simple_operator("INVOKE_REGION_PREVIEW")
        # bpy.ops.object.simple_operator("INVOKE_AREA")
        # bpy.ops.object.simple_operator("INVOKE_SCREEN")
        # bpy.ops.object.simple_operator("EXEC_DEFAULT")
        # bpy.ops.object.simple_operator("EXEC_REGION_WIN")
        # bpy.ops.object.simple_operator("EXEC_REGION_CHANNELS")
        # bpy.ops.object.simple_operator("EXEC_REGION_PREVIEW")
        # bpy.ops.object.simple_operator("EXEC_AREA")
        # bpy.ops.object.simple_operator("EXEC_SCREEN")
        # I tested 12 of them already

But you can simulate that situation through keyboard shortcut

import bpy
from bpy.types import PointerProperty

class ShareProps(bpy.types.Operator):
    test_float: bpy.props.FloatProperty()

class SimpleOperator(ShareProps):
    bl_idname = "object.simple_operator"
    bl_label = "Simple Object Operator"
    bl_options = {"REGISTER", "UNDO", "BLOCKING"}

    def execute(self, context):
        print(self.test_float)
        return {'FINISHED'}

class Main(ShareProps):
    bl_idname = "object.main"
    bl_label = "Main Operator"
    bl_options = {"REGISTER", "UNDO", "BLOCKING"}

    def __init__(self):
        kwargs = {}
        self.kwargs = kwargs

        for identifier, e in self.properties.bl_rna.properties.items():
            if isinstance(e, PointerProperty):
                continue
            
            kwargs[identifier] = getattr(self, identifier)

    def execute(self, context):
        kwargs = self.kwargs
        for k in kwargs:
            kwargs[k] = getattr(self, k)

        bpy.ops.object.simple_operator(**kwargs)
        return {'FINISHED'}


def register():
    bpy.utils.register_class(SimpleOperator)
    bpy.utils.register_class(Main)

#def unregister():

if __name__ == "__main__":
    register()

Maybe little help, as it won't solve the core problem.