OpenSimulationInterface
Problems with dynamic linking
Describe the feature
The OSI library must offer the possibility that within a C++ program (one process) two or more different OSI versions can be used simultaneously as dynamic libraries (shared libraries). This is not possible due to the "Custom Options" [1] in the current OSI version 3.X.X with the used FileOption (see [2]). and leads to the following runtime error:
[libprotobuf FATAL external/com_google_protobuf/src/google/protobuf/extension_set.cc:93] Multiple extension registrations for type "google.protobuf.FileOptions", field number 81000.
unknown file: Failure
C++ exception with description "Multiple extension registrations for type "google.protobuf.FileOptions", field number 81000." thrown in the test body.
[1] https://developers.google.com/protocol-buffers/docs/proto#customoptions [2] https://github.com/OpenSimulationInterface/open-simulation-interface/blob/6ae62d627fc10f40b6cb567989b94caab6502751/osi_version.proto.in#L54
Important note: As discussed a reminder for the v4.0 release (not backward compatible). This issue is uploaded by me on behalf of BMW.
@pmai @ThomasNaderBMW FYI
We at openPASS are also interested in having this problem solved :-)
Is there a fix planned for v4.0.0 or is it still in discussion?
I did some tests and found the "Multiple extension registrations" error to disappear, if I just don't access the extension. So if I don't use this code (or use it only once in the process), the usage of multiple libraries seems to be fine.
Feedback from my colleague Markus Schönbeck (sry it is German):
- Wenn man nicht den Sourcecode aller Komponenten unter Kontrolle hat, kann es dennoch zu diesem Problem kommen, wir haben keine Garantie, dass dies nicht benutzt wird.
- Letztendlich sollte dieser Fehler vollständig ausgeschlossen werden (wie von OpenPath anscheinend ja auch gewünscht).
- Etwas, was vorhanden ist, nicht zu benutzen, weil es sonst zu Problemen kommt, ist ein Design-Fehler ((selbst wenn der Workaround bei OpenPath zu funktionieren scheint).
Related: https://github.com/protocolbuffers/protobuf/issues/6029