Bug 447824 - Cannot create two aggregations between the same two classes
Summary: Cannot create two aggregations between the same two classes
Status: CONFIRMED
Alias: None
Product: umbrello
Classification: Applications
Component: general (show other bugs)
Version: Git
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Umbrello Development Group
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-01-02 12:25 UTC by Robert Hairgrove
Modified: 2022-01-03 06:06 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:


Attachments
Model of a simple graph structure (7.67 KB, image/png)
2022-01-02 12:25 UTC, Robert Hairgrove
Details
Reproduction using "Add Point" before adding the second association (13.61 KB, application/x-uml)
2022-01-02 14:04 UTC, Oliver Kellogg
Details

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Description Robert Hairgrove 2022-01-02 12:25:15 UTC
Created attachment 145048 [details]
Model of a simple graph structure

SUMMARY
Cannot create two aggregations between the same two classes. This is necessary if modeling a graph structure, for example (see attached picture of what I am trying to achieve).

STEPS TO REPRODUCE
1. Open a new class diagram, or use the default diagram;
2. Add two classes : Node and Edge;
3. Draw an aggregation from Edge to Node. Give it the role "source", multiplicity 1..1
4. Try to draw another aggregation similar to the above with role "target"

OBSERVED RESULT
The second aggregation is not created.

EXPECTED RESULT
Multiple aggregations should be possible.

SOFTWARE/OS VERSIONS
Linux: Ubuntu 18.04.x
(available in About System)
Qt Version: 5

ADDITIONAL INFORMATION
There is an interesting comment in the method body of "AssociationWidget::create()" which probably applies here. ;)
Comment 1 Oliver Kellogg 2022-01-02 14:04:12 UTC
Created attachment 145055 [details]
Reproduction using "Add Point" before adding the second association

In the attachment bug447824-mutual-aggreg.xmi I followed your steps but after creating the first association I right-clicked on the "source" association and selected "Add Point" and then moved the waypoint so that the association is not a straight line.
I could then add the second association.
The problem is that if the "Add Point" is left away then the second association line exactly overlaps the first.
I just tried this scenario and confirm in that case it is hard to distinguish the two, or add waypoints after the fact.