Fix explosion of already_processed

[amw]

already_processed was unnecessarily appended and extended during CSS tags generation.

It was repeatedly calling a.extend(a) causing memory explosion. With my app's assets it quickly went to 16 GB and caused my Django process to be OOM killed.

You can test this behavior:

>>> a = list(f'some-hashed-path-{i}' for i in range(100))
>>> for j in range(100):
...     print(f'Iteration {j}')
...     a.extend(a)
... 
Iteration 0
Iteration 1
Iteration 2
Iteration 3
Iteration 4
Iteration 5
Iteration 6
Iteration 7
Iteration 8
Iteration 9
Iteration 10
Iteration 11
Iteration 12
Iteration 13
Iteration 14
Iteration 15
Iteration 16
Iteration 17
Iteration 18
Iteration 19
Iteration 20
Iteration 21
Iteration 22
Iteration 23
Iteration 24
Killed

[rix1]

+1 Also happened to me! Looking forward to getting this merged 🎉

[MrBin99]

Thanks !

[knokit]

This also happened to me, had to downgrade to v2. Would be nice if this could be released. :)

[Niicck]

Hey ya'll. This has now been released in v3.0.2. Thanks so much for the fix!