PlantUML Generation fails if both edges point to "Ende": NotExactlyTwoOutgoingEdgesError

[hf-kklein]

Affects:

• E_0459
• E_0506
• E_0408
• E_0409
• E_0410
• E_0411
• E_0415
• E_0555
• E_0556
• E_0412
• E_0416
• E_0453
• E_0518
• E_0522
• E_0026
• E_0042
• E_0043
• E_0211
• E_0243
• E_0260
• E_0261
• E_0267
• E_1010

E.g. E_0459 in FV2310:

This leads to a
https://github.com/Hochfrequenz/ebdtable2graph/blob/c8915eafae24777c2885995af5f06fab1a5450ab/src/ebdtable2graph/plantuml.py#L89

Either this is prevents crashes downstream in PlantUML (then we should add a comment why we raise the error) or the assertion is not as precise as it needs to be (then we should fix it).

[lord-haffi]

Imo this error is absolutely reasonable. I'd place it somewhere else though. I'd like to have only string conversion logic in the string convertion function. You could place it e.g. when investigating the single nodes.
However, if you want to support multiple edges pointing from and to the same nodes, you'll have to use MultiDiGraph instead of DiGraph. This change maybe breaks the code somewhere else, I don't know.

[hf-kklein]

tldr: this is a feature on our side to prevent creation of puml code that might lead to wrong SVGs when used in plantuml. @lord-haffi will explain in the code.

[lord-haffi]

tldr: this is a feature on our side to prevent creation of puml code that might lead to wrong SVGs when used in plantuml. @lord-haffi will explain in the code.

No, not this. This is a bug :) Or to be more precise: Currently, unsupported. As I mentioned:

if you want to support multiple edges pointing from and to the same nodes, you'll have to use MultiDiGraph instead of DiGraph.

What you are talking about is "Graph too complex" (see #100) but has nothing to do with this issue.