As discussed in the initial fuzzing integration PR¹,fuzz_tree.py's implementation was not ideal in terms of coverage and its reading/writing to hard-coded paths inside/tmp was problematic as (among other concerns), it causes intermittent crashes on ClusterFuzz² when multiple workers execute the test at the same time on the same machine.

The changes here replacefuzz_tree.py completely with a completely newfuzz_repo.py fuzz target which:

• Usestempfile.TemporaryDirectory() to safely manage tmpdir creation and tear down, including during multi-worker execution runs.
• Retains the same feature coverage asfuzz_tree.py, but it also adds considerably more from much smaller data inputs and with less memory consumed (and it doesn't even have a seed corpus or target specific dictionary yet.)
• Can likely be improved further in the future by exercising additional features ofRepo to the harness.

Here are some very rough stats to give a very rough idea of the difference:

Note on License

Becausefuzz_tree.py was removed andfuzz_repo.py was not derived from it, the Apache License call outs in the docs were also updated as they only apply to the singefuzz_config.py file now.