ff.c has a lazy-mounting feature, where any filesystem call will mount
the volume if it can. This messes with predictability of the mounted
state, so all (except mount/unmount/mkfs) Python functions will first
check if the fs is mounted.
Instead of having possibly multiple FatFS objects, each with its own
`fs` struct, there is one global static fs_instance. This is to match
the mode of operation of ff.c, which assumes a global list of mounts,
and all functions operate on the global based on path.
Methods of FatFS were converted to functions on the fatfs module.
fatfs.unmount() does not call ff.c's unmount, but simply invalidates
fs_instance. This is basically what ff.c would do, except without
messing with ff.c's global list of mounts.
It is possible to call `ensure_sdcard` in a way that requires only SD
card be inserted, but not necessarily formatted.
This is useful for SD-protect and possibly other use-cases where the SD
card is read-only, and "not formatted" is identical to "not containing
the right files".
Click REALLY INSISTS you provide on/off switches for your options.
You can use is_flag, but then the presence of the option changes based
on the default value.
Which makes sense, really:
@option("-f", "foobar", is_flag=True, default=False)
you would expect `./cli -f` to have `foobar is True`
whereas with
@option("-f", "foobar", is_flag=True, default=True)
you would expect `./cli -f` to have `foobar is False`, otherwise it's a
no-op
this becomes fun with `default=os.environ.get("SOMETHING")`, because
then the effect of the option CHANGES with a value of environment
variable!
there's two ways around this:
a) don't use defaults, update the flag explicitly, like:
foobar = foobar or os.environ.get("FOOBAR") == "1"
b) forget about is_flag and specify an on/off switch, where the default
value works as intended
since the latter is also technically speaking more correct, i'm doing it
