Add mpy version number to lib folder name
kattni opened this issue · comments
It's an historical accident that the mpy version (2,3) coincides with the 2.x and 3.x releases.
ok im not 100% sure what we're solving anymore. lets chat monday!
What is the context for this?
The point of this is that when the .mpy version changes, the old lib directory becomes unusable. I've seen a number of support cases where it took some time for someone upgrading from CircuitPython 2.x to 3.x to realize they had to update lib. Sometimes their main.py crashed hard enough that the board was unusable and they had to reinstall 2.x temporarily.
If the lib directories included the mpy version (lib2, lib3), and only that directory was on sys.path, then a mismatched lib directory wouldn't be accessed at all. There'd still be an error, but it might be less confusing. This is vaguely similar to how there are separate library directories for CPython 2.x and 3.x on host OS's.
One issue is that we're not going to see an mpy version bump in CPy 4.0, so the mpy version will no longer (accidentally) line up with the CPy version. The digit in lib2 and lib3 could refer to the mpy version or the CPy version. Since there's no mpy version bump from CPy 3.x to 4.x (probably), maybe the lib directory should be called lib34. On the other hand, there may be other differences between libraries between 3.x and 4.x (e.g. changing UART timeout from msecs to seconds), and maybe we want to think about library versions in the long run.
I floated this more as an idea to spur thinking about library version management -- I'm not sure if this particular idea is the best, but it solves a particular support problem.
Just my 2 cents.
I'm not convinced it is necessary or desirable to change the name of the folder.
Is this just to deal with the .mpy format change? If so, do we expect that to happen frequently, if ever again?
The actual libraries are not different for CP2 vs CP3 except for a few places where I think they internally detect and deal with the difference so I don't think we really have to complicate things for this.
After discussion we've decided the best route to go is to add a specific flash code into the CircuitPython error flash codes. We're going to add pulsing blue to be specific to the Incompatible mpy error to resolve this.
Closing in favor of: adafruit/circuitpython#1369