[BotnEyedJoe]

Oh, hah! The one piece of information I left out, that this is on an 8-slot cRIO, turns out to be the key. And this issue turns out to be caused not at all by RobotPy, but by the cRIO image v43, for cRIOFRC (the 8-slot version).

There are two versions of nivision.out delivered as part the v43 cRIO image, one for the 4-slot and another for the 8-slot cRIO. It turns out that they do not both have the same symbol table.

All of the "undefined" symbols I quoted in the prior message are defined in the cRIOFRC2 (4-slot) version of nivision.out, but *not* in the cRIOFRC (8-slot) version.

So I worked around this by commenting out these symbols from the Packages/nivision/sip/nivisionmod.sip file and rebuilding RobotPy. And so the code fragment I showed before now works fine.