adding __contains__ stub to displayio.Group

[FoamyGuy]

resolves: #7948

I noticed that mypy raises this error while testing some of the suggested fixes discussed during the weeds section of the meeting inside of this PR: adafruit/Adafruit_CircuitPython_DisplayIO_Layout#85

This topic of the in operator didn't come up, but I noticed mypy outputting errors about it while working on that.

I tested the change successfully by building stubs and installing with pip install . and then running mypy on that PR branch again. Confirmed that it no longer outputs the error.

[tannewt]

Does it actually work? It isn't clear to me how it works.

[FoamyGuy]

Does it actually work? It isn't clear to me how it works.

It does work to eliminate that error from mypy. I'm not entirely sure of the 'how' beyond that mypy is looking at your installed libraries for known types when it runs to try to enforce it's rules. circuitpython-stubs seems to be where it's taking it's definition for displayio.Group.

I saw your message on the issue as well. Iter does feel more appropriate for this instance, although I think Group may support both. I'll double check whether it does support if something in group and if not I'll change the contains one to iter. If it supports both is it worth leaving contains and adding iter to the stubs? It may not make a difference for mypy since it does seem slightly confused about which one is used, but it will add more specific clarity in the docs pages.

[tannewt]

If it supports both is it worth leaving contains and adding iter to the stubs?

Yup. But I don't think it supports contains. :-) I was talking about how it was implemented in CP. mypy is just a knock on effect.

[FoamyGuy]

Latest commit adds __iter__stub.

As far as I can tell it supports both for _ in Group and if _ in Group. The following code executes successfully and outputs expected results:

import displayio
import board

bmp = displayio.Bitmap(100,100, 1)
palette = displayio.Palette(1)
palette[0] = 0x00ff00
tilegrid = displayio.TileGrid(bitmap=bmp, pixel_shader=palette)
bmp.fill(0)
main_group = displayio.Group()

main_group.append(tilegrid)
board.DISPLAY.show(main_group)

if tilegrid in main_group:
    print("tilegrid is in main_group")
else:
    print("Not in main group")

for _item in main_group:
    print(_item)
while True:
    pass

Output:

code.py output:
tilegrid is in main_group
<TileGrid>

Tested on:

Adafruit CircuitPython 8.1.0-beta.2 on 2023-04-26; Adafruit Feather ESP32-S2 TFT with ESP32S2
Board ID:adafruit_feather_esp32s2_tft

[tannewt]

Thanks!