i would expect the same result but instead nothing happens and no face sets are created

https://docs.blender.org/api/current/bpy.ops.sculpt.html
Is that supported by the API ?

Also, since you asked it on support channel, I'm tempted to close it as support request.

https://docs.blender.org/api/2.83/bpy.ops.sculpt.html

Facesets should be supported in the 2.83 api. I'm guessing there is something stopping it for the time being.

@dan grauer (kromar) I think what you need to do is override context of operator. It is probably "confused" by instruction to select face masks in console https://docs.blender.org/api/current/bpy.ops.html#overriding-context

@Richard Antalik (ISS)
i was looking into the context and when i print the mode and the active obejct it gives me the correct context. i have not tried overriding it since it seems to be correct. might there be some other context that confuses the operator?

import bpy
print(bpy.context.active_object) > <bpy_struct, Object("FrontCasing")> (the correct active object)
print(bpy.context.mode) > SCULPT
bpy.ops.sculpt.face_sets_init(mode='LOOSE_PARTS')

In T76324#923996, @dan grauer (kromar) wrote:

@Richard Antalik (ISS)
i was looking into the context and when i print the mode and the active obejct it gives me the correct context. i have not tried overriding it since it seems to be correct. might there be some other context that confuses the operator?

import bpy
print(bpy.context.active_object) > <bpy_struct, Object("FrontCasing")> (the correct active object)
print(bpy.context.mode) > SCULPT
bpy.ops.sculpt.face_sets_init(mode='LOOSE_PARTS')

Yes, selected object and mode are "global". Problem is that editor from within you run operator is not.

The idea of overriding context is that you want to trick operator that it is executed from different editor

you nedd to do something like bpy.ops.transform.seq_slide({'area':editor_area}, value = (0,distance)) and you have to search for editor_area.

i tried to override the context as in the documentation ( https://docs.blender.org/api/current/bpy.ops.html#overriding-context ) and also the way you described but i can not get it to work.

import bpy
bpy.ops.object.mode_set(mode='SCULPT')  ## **is working**

for window in bpy.context.window_manager.windows:
    screen = window.screen

    for area in screen.areas:
        if area.type == 'VIEW_3D':
            override = {'window': window, 'screen': screen, 'area': area}
            #bpy.ops.screen.screen_full_area(override)         
            bpy.ops.sculpt.face_sets_create(override, mode='VISIBLE') ## **not working **

            #bpy.ops.paint.mask_flood_fill(mode='VALUE', value=1)    ## **is working**
            bpy.ops.sculpt.dirty_mask()                              ## **is working**
            break

In T76324#926389, @dan grauer (kromar) wrote:

i tried to override the context as in the documentation ( https://docs.blender.org/api/current/bpy.ops.html#overriding-context ) and also the way you described but i can not get it to work.

import bpy
bpy.ops.object.mode_set(mode='SCULPT')  ## **is working**

for window in bpy.context.window_manager.windows:
    screen = window.screen

    for area in screen.areas:
        if area.type == 'VIEW_3D':
            override = {'window': window, 'screen': screen, 'area': area}
            #bpy.ops.screen.screen_full_area(override)         
            bpy.ops.sculpt.face_sets_create(override, mode='VISIBLE') ## **not working **

            #bpy.ops.paint.mask_flood_fill(mode='VALUE', value=1)    ## **is working**
            bpy.ops.sculpt.dirty_mask()                              ## **is working**
            break

I thought there may be some issue, but after digging in code it seems, that there isn't.
Turns out, that you don't even need to override context, but rather execution context https://docs.blender.org/api/current/bpy.ops.html#execution-context

Pass 'INVOKE_DEFAULT' as first parameter.
bpy.ops.sculpt.face_sets_create('INVOKE_DEFAULT', mode='VISIBLE')

I have done this only 2 times really so I don't know much about this off top of my head. Sorry for misleading you.

Unfortunately unless you look at operator code, you don't really know if you want to call invoke() or exec() function and this is kinda low-level even for quite advanced users.
Sometimes you may need to override both contexts I guess.

There actually was a bug here, though the operator API is not strictly defined enough for it to be clear. By convention operators should always implement exec() for non-interactive execution, with only a few exceptions.

In T76324#926525, @Brecht Van Lommel (brecht) wrote:

There actually was a bug here, though the operator API is not strictly defined enough for it to be clear. By convention operators should always implement exec() for non-interactive execution, with only a few exceptions.

Thanks for clarification. I have seen quite a few operators without exec function, so I probably wouldn't consider this a bug (not working as designed)
Makes sense to consider this a bug though, so I will keep it in mind.