PixelArray raise error assigning sequence to pixel

[ankith26]

fixes #2740

• In the pixelarray module, any sequence (except tuple and pygame.Color) isn't considered a "color", but rather a pixel sequence
• The segfault happens because the code expects a pixelarray upon subscripting for assignment, but receives an "integer color"

I am open to suggestions on how to improve the error message, can't think of something descriptive enough ATM.

[oddbookworm]

I take it the segfault is reproducible? If so, I'd like to see a regression test

[ankith26]

Have added the regression test, thanks for pointing it out

[oddbookworm]

LGTM!

[narilee2006]

Why not convert the PyList to a PyTuple? No errors, no worries.

static int
_pxarray_ass_item(pgPixelArrayObject *array, Py_ssize_t index, PyObject *value)
{
    // Shortened code...

    if (PyList_Check(value))
        value = PyList_AsTuple(value);

[ankith26]

That is a behaviour change that deviates from the specification of the pixelarray module. According to the docs:

For assignment, a tuple can only be a color. Any other sequence type is a sequence of colors.

[MyreMylar]

LGTM 👍