Bug in parallel execution

[vedran-kasalica]

Sometimes the error occurs when the code figures are generated in parallel.
Parallel execution_error.txt

[vedran-kasalica]

Bug is in the pipeline, but the reason might be the graphviz-java library used to print the graphs in the process.

[eladrion]

@vedran-kasalica The text file is not accessible anymore. Can you provide more information what exactly the error is?

[vedran-kasalica]

Parallel.execution_error.txt

[eladrion]

Traced down on the basis of the backtrace to this line. Inspecting further

[eladrion]

More specifically, the NPE is thrown here, presumably

[eladrion]

Graphviz.fromGraph(graph).render(Format.PNG).toFile(file);

throws an error and fails (according to the backTrace) in the process of executing toFile. Looking into the GraphViz-Java API, the trace resolves to (in version 0.10.0) to the following line:

getEngine().execute(src, options, rasterizer);

This indicates that the call to execute fails due to the "Engine" being NULL. So the cause might be GraphViz, indeed.

@vedran-kasalica : I would tend to close this bug for now since I think, this could be a dependency issue. We are using GraphViz 0.17.0, currently. What do you think?

[vedran-kasalica]

This issue can be closed, but GraphViz Java lib is not being developed since 2021, so maybe there should be a new issue to switch to a more up-to-date library.