sagas/mpy: Use main module name instead of __main__.

[laurensvalk]

This is separate from Python's __main__ mechanism, so we shouldn't be manually renaming things to __main__ here.

This also makes file names show correctly on EV3.

See pybricks/support#2364

[dlech]

Is there any version of the firmware that checks for the name __main__.mpy? Or do all versions of the firmware just use the first file as the entry point?

[laurensvalk]

Thanks. Hmm, because we do show the update warning, my brain was at this one:

We can work around this by making a file literally named __main__.py if we ever need to do a git bisect and run a program on the hub.

Originally posted by @dlech in #2364

But that was about the intermediate versions, and we probably still do need the following:

@dlech indicated we can just have Pybricks Code check the protocol version to use __main__ for older firmware. I'm all for it 👍

Originally posted by @laurensvalk in #2364

But we don't have access to the currently active version in that module, so needs some more work.

[dlech]

Should do the trick:

    const fwVersion = yield* select((s: RootState) => s.hub.deviceFirmwareVersion);

If it is empty string (because not connected to a hub), then use the "new" way since we are just doing compile check and not downloading.

[dlech]

Or if we want to be fancy, we could add a new state flag like useLegacyStartUserProgram that is useLegacyDunderMain.

[laurensvalk]

Should do the trick:

Heh, I started that way but thought you'd call me out on that 😄

Or if we want to be fancy, we could add a new state flag like useLegacyStartUserProgram that is useLegacyDunderMain.

So that is indeed what I tried. I'm always a little puzzled doing this, as there seem to be so many placed to add a single boolean condition.

[dlech]

as there seem to be so many places to add a single boolean condition.

I think it would be fine to do:

const useLegacyMainModule = yield* select((s: RootState) => s.hub.useLegacyMainModule);

In the mpy saga so that we don't have to add it as a parameter to the action.