OnboardCellularInterface used incorrectly

[kjbracey]

This example invokes methods on OnboardCellularInterface that are not part of the CellularBase abstract class. This means it may not work if OnboardCellularInterface is not a PPPCellularInterface.

OnboardCellularInterface is documented as potentially being any class derived from CellularBase, depending on platform, so portable code should use only CellularBase methods.

ARMmbed/mbed-os#6082 has worked around this by adding the same extensions to its EasyCellularInterface, but that should not have been necessary.

This can probably be fixed for mbed OS 5.9 as part of shifting from OnboardCellularInterface to CellularBase::get_default_instance() or CellularDevice::get_default_instance() - see ARMmbed/mbed-os#6108

[ciarmcom]

ARM Internal Ref: IOTCELL-651

[AriParkkila]

Example app uses only methods from CellularBase as there is no need to call iface.modem_debug_on anymore. That was changed to compile time definition cellular.debug-at in https://github.com/ARMmbed/mbed-os-example-cellular/blob/mbed-os-5.9.0-oob/mbed_app.json

[AriParkkila]

@kjbracey-arm does the fix look like we could close this issue?

[kjbracey]

I still see the modem_debug_on in master.

If you just deleted that, it probably clears the issue for now, but it could easily recur as long as you're directly instantiating and using the object. It would be nice enforce the abstraction by using CellularBase::get_default_instance() (now in 5.9) and just a CellularBase pointer.

5.9.0 doesn't have a CellularBase-to-CellularDevice (or whatever) mapping API to check for advanced facilities. That's something else to look at at some point.

[AriParkkila]

Ok, I see there are two problems to fix:

• Only use CellularBase methods (remove modem_debug_on)
• Instantiate CellularBase::get_default_instance() instead of OnboardCellularInterface

[kjbracey]

Yep. Doing the second ensures you've done the first.

[AriParkkila]

@kjbracey-arm please check PR #83

[AriParkkila]

Fix is now merged in the mbed-os-5.9.0-oob branch.

This issue can be closed when mbed-os-5.9.0-oob is merged to master.

[AriParkkila]

@kjbracey-arm can we close this issue?

[AriParkkila]

As there has been no further requests, I'm closing this issue now.