The fuzz generates new inputs but changes the data structure

[Bubble-mt]

When I use the tool to test a function which has complex input parameters, such as list, dictionary or etc, the afl fuzz would generate new inputs, but the input data structure would be changed to be different with what I want, so when I run py fuzz, I get crashes that I don't want.
Is this an issue? Or how I should using python afl to test these functions?

[koltiradw]

Hi! You probably need to use structure aware mutators for this. Look this https://github.com/google/libprotobuf-mutator.

[jwilk]

AFL gives you a sequence of arbitrary bytes.
It's up to you to convert that into a data structure you want without raising exceptions.