Cannot deploy PPLs which contain JSONtext to LV RT

[Brant Bergdoll]

Starting with package version 1.5.4.98, any vi which contains JSONtext and is built into a PPL cannot be deployed to LabVIEW RT. This issue does not occur when building an application into an RT exe or if the PPL is built for the host or Windows. NI support has been able to duplicate the issue across different bitness of LV and in LV versions 2021, 2022, and 2023 Q1.

[James Powell]

Does it work for the version before 1.5.4? And does NI support have any useful insight into what is causing the problem?

[Brant Bergdoll]

Yes, versions before 1.5.4 are able to deployed to LV within a PPL. NI support has been pointing to the Pretty Print.vi function without any additional information. I’ve asked support for additional details on how a developer would know what exactly is the cause of the failure to deploy.

[James Powell]

I suggest you try removing the “Pretty Print” and “Minify” functions and see if PPLs work then, just to be sure they are the problem.

[Ed Sekel]

I was able to work around this issue. It seems the problem is using a malleable VI (VIM) that has a class input (LVClass Serializer). If you right-click on the malleable VIMs after you wire them on your block diagram and convert them to a standard VI you should have success deploying the PPL to the real-time target. No issues were found with the “pretty print” or “minify” functions. Hope this helps!

[Andres Gomez]

I ran into this issue ~3 years ago with 1.5.4, and had to go back indeed to 1.4.5.91 to make it work.
I just spent almost one day fighting this again with the latest version, just only to realize it was the same issue I had seen at that point in the past.
My work-around moving forward will be changing all my source to use the Variant API (i.e. JSON text to Variant.vi) and avoid using the malleable VIs (at least for RT). This might be more of a LV issue than a JSONtext issue, could be interesting to get a simplified reproducing case and report it to NI support.

[Ed Sekel]

This issue has been reported to NI and resulted in a CAR.