cpython actually makes sure the newly chained exception doesn't create
a cycle (even indirectly); see _PyErr_SetObject use of "Floyd's cycle
detection algo". We'll go for the simpler solution of just checking
one level deep until it's clear we need to do more.
Closes: #7414
This may help address #7409 if the underlying cause is the deterministic
volume ID. However, not all boards have working urandom (samd21
at least does not) so a couple of fallbacks are attempted when it fails.
I verified that on a pico_w, each `storage.erase_filesystem()` gives
a distinct 32-bit volume ID (pico_w's urandom can never fail)
The conversion of characters like _space_ in qstrs is a bit
ad-hoc. Because "_not_" stands for the logical negation character ¬
the recently added message was displayed incorrectly:
```
>>> socket.getaddrinfo('does.not.exist', 0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
gaierror: (-2, 'Name or service_space¬space_known')
```
I had noticed this, but evidently failed to include the fix in
the problem in #7269.
MP_REGISTER_MODULE would use identifiers like
"MODULE_DEF_MP_QSTR___FUTURE__" which would in turn cause
a QSTR to be generated for it. This wasn't desirable, because the
qstr would never be used.
This clears out quite a bit of flash storage on the proxlight trinkey.
This adds the __cause__, __context__ and __suppress_context__
members to exception objects and makes e.g., `raise exc from cause`
set them in the same way as standard Python.
.. a fast helper for animations. It is similar to and inspired by the
PixelMap helper in Adafruit LED Animation library, but with an extremely
fast 'paste' method for setting a series of pixels. This is a common
operation for many animations, and can give a substantial speed improvement.
It's named `adafruit_pixelmap` so that we can package a compatible version
in pure Python for systems that can't fit it in C in flash, or for
Blinka.
This is a proof of concept and can make a very fast comet animation:
```python
import time
import adafruit_pixelbuf
import adafruti_pixelmap
import board
import neopixel
from supervisor import ticks_ms
from adafruit_led_animation.animation.solid import Solid
from adafruit_led_animation import color
pixel_pin = board.GP0
pixel_num = 96
pixels = neopixel.NeoPixel(pixel_pin, pixel_num, brightness=1, auto_write=False, pixel_order="RGB")
evens = adafruit_pixelmap.PixelMap(pixels, tuple(range(0, pixel_num, 2)))
odd_indices = tuple((i, i+2) for i in range(1, pixel_num, 4))
print(odd_indices)
odds = adafruit_pixelbuf.PixelMap(pixels, odd_indices)
assert len(odds) == len(odd_indices)
comet_length = 16
comet1 = [color.calculate_intensity(color.GREEN, ((1+i) / comet_length) ** 2.4)
for i in range(comet_length)]
comet2 = [color.calculate_intensity(color.PURPLE, ((1+i) / comet_length) ** 2.4)
for i in range(comet_length)]
pos1 = 0
pos2 = 96//4
while True:
evens.paste(comet1, pos1, wrap=True, reverse=False, others=0)
pos1 = (pos1 + 1) % len(evens)
odds.paste(comet2, pos2, wrap=True, reverse=True, others=0)
pos2 = (pos2 - 1) % len(odds)
pixels.show()
m = ticks_ms()
if m % 2000 > 1000:
time.sleep(.02)
```
