Update smbus.py

[zapper1942]

I recently upgraded Pi OS to Trixie for my project and this plugin started failing with the error "TypeError: 'memoryview' object cannot be interpreted as an integer" with Python 3.13.
https://github.com/zapper1942/mechanical-pi-clock/blob/main/pi_clock.py
I had to make this change to get it working again

AI Explanation:

In Python 3.13, when Adafruit's I2C layer reads data blocks, it passes a memoryview object instead of a direct byte array. Without the change (cmd[0] = reg), is rejected as a TypeError

By switching to (cmd[0] = reg[0]), the code now extracts the integer out of the data wrapper regardless of whether that wrapper is an old-school bytes object (Python3.12) or a new (Python 3.13) memoryview

I have not tested it on python3.12 however

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[makermelissa-ai-assistant]

The proposed change fixes a one-byte memoryview, but introduces two correctness regressions:

• The standard read_i2c_block_data(addr, register_int, length) form now raises TypeError: 'int' object is not subscriptable at reg[0].
• Blinka passes the complete write-buffer slice here, so a memoryview can contain multiple command bytes. Wrapping it in a one-byte bytearray and using only reg[0] silently truncates that command.

With ioctl mocked, the base version sent 12 for an integer command; this PR raised TypeError. A two-byte memoryview containing 12 34 was accepted by this PR but only 12 was sent.

A minimal fix is to treat memoryview as an existing buffer and retain the original integer conversion:

if not isinstance(cmd, (bytes, bytearray, memoryview)):
    reg = cmd
    cmd = bytearray(1)
    cmd[0] = reg

I tested that version with integer, bytes, bytearray, and one- and two-byte memoryview commands; each preserved the expected command bytes.

[makermelissa]

Please see my AI assistant's comments, which reflected my concern anyways.

[makermelissa]

I updated the repo, so it should pass CI now.

[zapper1942]

Thanks for the feedback. I've implemented the suggestion and it is also working locally.

[makermelissa]

Thank you. Looks good.