Certain Nodes Blocks Edit Source Node of Selection (Alt + E) in viewer | SceneAlgo.history bug

[LinasBeres]

Version: Gaffer 1.2.x-linux
Third-party tools: None
Third-party modules: None

Description

Certain nodes block seeing the "correct" edit source node of selection (Alt + e).

The ones that cause this issue (so far) are MeshType and OSLObject, but freezeTransform is "seen through" by the hotkey.

It is not completely certain what should be the correct functionality of the hotkey.

Steps to reproduce

1. Link a plane to meshType
2. Select plane in viewer
3. Hit Alt+e in the viewer
4. meshType opens up instead of plane

Example File

import Gaffer
import GafferImage
import GafferOSL
import GafferScene
import IECore

__children = {}

__children["Plane"] = GafferScene.Plane( "Plane" )
parent.addChild( __children["Plane"] )
__children["MeshType"] = GafferScene.MeshType( "MeshType" )
parent.addChild( __children["MeshType"] )
__children["PathFilter"] = GafferScene.PathFilter( "PathFilter" )
parent.addChild( __children["PathFilter"] )

__children["MeshType"]["in"].setInput( __children["Plane"]["out"] )
__children["MeshType"]["filter"].setInput( __children["PathFilter"]["out"] )
__children["PathFilter"]["paths"].setValue( IECore.StringVectorData( [ '/plane' ] ) )


del __children

@danieldresser also used this following script to indicate that the scene history is not going any further than the MeshType for the above scene.

hist = GafferScene.SceneAlgo.history( root['MeshType']['out']['object'], "/plane" )

def printPredecessors( h, depth ):
    for i in h.predecessors:
        print( "\t" * depth + i.scene.fullName() )
        printPredecessors( i, depth + 1 )    

printPredecessors( hist, 0 )

[johnhaddon]

Duplicate of #3875.

I believe this is the offending code : https://github.com/GafferHQ/gaffer/blob/main/src/GafferScene/SceneAlgo.cpp#L415-L427. It ignores the private internal plug that we use for computing the processed object, truncating the history as demonstrated in Daniel's script.