New ways to fuzz Python via code generation

[devdanzin]

Currently fusil generates random function and method calls, also calling them from threads, as a way to fuzz Python.

Some ideas to improve on that include adding async execution, object mangling and exercising the JIT.

This discussion aims to gather more ways of adding options to fuzzing Python, so that more issues can be found. What do you think would be a good fuzzing vector to be added?

[devdanzin]

Object mangling and async execution have been added, with little benefit.

Weird subclasses of builtin types with many common methods added (to allow them getting used further into code that expects different types) have been added. This found some success: 3 new crashers and rediscovery of another one.

[devdanzin]

We now have a varied array of code generation and mutation strategies in fusil.

We now also have a sister project, lafleur which fuzzes the CPython JIT via feedback driven mutations.