Object Model Reporting issues with CAN connected Expansion boards - "unsupported type code 24"

[T3P3]

Only checked in SBC mode thus far.
Impacts 3.6.beta1 and 3.6.beta2 (other versions not checked)
Various OM keys within boards[] do not report correctly for expansion boards. e.g:

boards[1].firmwareDate
boards[1].firmwareFileName
boards[1].firmwareVersion
boards[1].name
boards[1].shortName

In all cases these report:
unsupported type code 24

Other keys do report correctly, e.g.:

boards[1].drivers[0].status
boards[1].uniqueId
boards[1].state

Work around:
Appending an empty string to the query/use of the result works:

e.g.

echo (boards[1].firmwareVersion^"")
global firmwareVersionTB = (boards[1].firmwareVersion^"")

[dc42]

Works OK for me in standalone mode:

echo boards[1].firmwareVersion
3.6.0-beta.2
echo boards[1].firmwareFileName
Duet3Firmware_EXP3HC.bin
echo boards[3].firmwareVersion
3.6.0-beta.1+1
echo boards[4].firmwareFileName
Duet3Firmware_SZP.bin

The "unsupported type code" message comes from file DataTransfer.cpp so it SBC-specific. The full list of expression type codes is defined in file ObjectMode/TypeCode.h. TypeCode::CanExpansionBoardDetails is code 24. I think the code in DataTransfer just needs to call ExpressionValue::ExtractRequestedPart to handle this case.

[chrishamm]

That's right, TypeCode::CanExpansionBoardDetails wasn't supported in DataTransfer.cpp. My fix looks a bit different but it works as well - the underlying code calls ExtractRequestedPart, too. Please merge it into 3.5-dev and 3.6-dev.