Return type of Decoder.read changed between 2.8.0 to 3.0.0

[radon-at-beeper]

I noticed that tests for https://github.com/m1stadev/PyIMG4 were failing on Arch: https://aur.archlinux.org/packages/python-pyimg4. Upon investigating, I saw the reason was that python-asn1 was upgraded from 2.8.0 to 3.0.0 and PyIMG4 encounters an error with the new API.

However, on checking https://github.com/andrivet/python-asn1/releases/tag/v3.0.0 I see that this release was supposed to be backwards-compatible, so I figure the change in behavior might have been unintentional?

Here is a test file: https://github.com/m1stadev/PyIMG4/blob/master/tests/bin/IM4M

>>> data = open("IM4M", "rb").read()
>>> dec = asn1.Decoder()
>>> dec.start(data)

Then on version 3.x:

>>> type(dec.read()[1])
<class 'list'>

Whereas on version 2.x:

>>> type(dec.read()[1])
<class 'bytes'>

The change in return type results in an error because PyIMG4 expects a binary stream to be returned. Is this a bug or should PyIMG4 be updated to handle both cases?

[andrivet]

Since 3.0 is a major upgrade, there may be some subtle changes in the API depending on the input data. So I am not sure if it is a bug or not. I will look at this when I get some time.