0002902: PyObjectBase notification chain can lead to unexpected changes to document - FreeCAD Tracker

NOTICE: Migration to GitHub Issues

On Feb 7, 2022, the FreeCAD project migrated all issues from this site at tracker.freecad.org to our main GitHub repository. All new bugs must be submitted there.
This Mantis repository is in read-only mode and will be retained for reference as long as it is useful.

For details please see the announcement at the Forums: https://forum.freecadweb.org/viewtopic.php?p=555883#p555883

ID	Project	Category	View Status	Date Submitted	Last Update

0002902	FreeCAD	Bug	public	2017-02-12 18:20	2017-04-02 17:34

Reporter	DeepSOIC	Assigned To	wmayer
Priority	high	Severity	major	Reproducibility	always
Status	closed	Resolution	fixed
Product Version	0.17
Fixed in Version	0.17

Summary	0002902: PyObjectBase notification chain can lead to unexpected changes to document
Description	Changing an object behind PropertyLinkSub may cause the link to stick to that object. It's hard to describe, see steps to reproduce.
Steps To Reproduce	1. Open the attached file. It contains a Cube, a Cylinder, and a 3d offset applied to Cylinder. 2. Now, run this in Py console `App.ActiveDocument.Offset.Source # doesn't do anything, huh? But it makes Cylinder think its parent object is Offset!` 3. Now this: `App.ActiveDocument.Offset.Source = App.ActiveDocument.Box # move offset over to Box App.ActiveDocument.recompute()` Now, Offset is applied to Cube instead of cylinder. So far so good. 4. and now this: `App.ActiveDocument.getObject("Cylinder").Placement = App.Placement() App.ActiveDocument.recompute()` This shouldn't do anything at all. But, Offset is now applied to Cylinder instead of Box!
Additional Information	forum thread: https://forum.freecadweb.org/viewtopic.php?f=10&t=20597&p=159579#p159579 OS: Windows 10 Word size of OS: 64-bit Word size of FreeCAD: 64-bit Version: 0.17.9933 (Git) Build type: Release Branch: master Hash: 6c3b78e97bbb8653e1189038c99682becef71626 Python version: 2.7.8 Qt version: 4.8.7 Coin version: 4.0.0a OCC version: 7.0.0 Note that it's important to obtain Cylinder object not as an attribute. I used getObject() method here, but the reference may also come from getSelection().
Tags	No tags attached.

FreeCAD Information

FreeCAD: master b72aa9f3 2017-02-13 23:32:30 wmayer Details Diff	issue 0002902: PyObjectBase notification chain can lead to unexpected changes to document		Affected Issues 0002902
	mod - src/Base/PyObjectBase.cpp		Diff File
	mod - src/Base/PyObjectBase.h		Diff File
	mod - src/Mod/Test/Document.py		Diff File
FreeCAD: master 4f23b569 2017-02-14 12:09:09 wmayer Details Diff	issue 0002902: replace members of PyObjectBase with a PyDictObject		Affected Issues 0002902
	mod - src/Base/PyObjectBase.cpp		Diff File
	mod - src/Base/PyObjectBase.h		Diff File
FreeCAD: master 19111f1e 2017-02-14 15:38:38 wmayer Details Diff	issue 0002902: track attribute objects in parent structure to notify about changes		Affected Issues 0002902
	mod - src/Base/PyObjectBase.cpp		Diff File
	mod - src/Base/PyObjectBase.h		Diff File
FreeCAD: master f4d8945d 2017-02-14 15:41:14 wmayer Details Diff	issue 0002902: add unit test		Affected Issues 0002902
	mod - src/Mod/Test/Document.py		Diff File

Date Modified	Username	Field	Change
2017-02-12 18:20	DeepSOIC	New Issue
2017-02-12 18:20	DeepSOIC	File Added: link-change-example.FCStd
2017-02-12 18:22	DeepSOIC	Additional Information Updated
2017-02-13 23:32	wmayer	Changeset attached	=> FreeCAD Master master b72aa9f3
2017-02-13 23:33	wmayer	Status	new => closed
2017-02-13 23:33	wmayer	Assigned To	=> wmayer
2017-02-13 23:33	wmayer	Resolution	open => fixed
2017-02-13 23:33	wmayer	Fixed in Version	=> 0.17
2017-02-14 15:44	wmayer	Changeset attached	=> FreeCAD Master master 4f23b569
2017-02-14 15:44	wmayer	Changeset attached	=> FreeCAD Master master 19111f1e
2017-02-14 15:44	wmayer	Changeset attached	=> FreeCAD Master master f4d8945d
2017-04-02 17:34	DeepSOIC	Relationship added	related to 0002996