In planning: Improve call sequence shrinking

[anishnaik]

It seems like echidna has a different heuristic for call sequence shrinking that might be more optimal than medusa's. There should be research into the differences b/w the two strategies and whether medusa can benefit from employing echidna's strategy more closely.

[0xalpharush]

I'm not sure why this isn't 100% given we want to try to shrink the value every single time

medusa/fuzzing/fuzzer.go

Line 473 in e471c52

ShrinkValueProbability: 0.1,

Echidna will consistently shrink to roughly setStruct((10, 87489408786382356735958, "\NUL", (80, false))) but medusa will not (run ./medusa fuzz --target fuzzing/testdata/contracts/value_generation/match_structs_xy.sol in the root of the repo). Perhaps the string shrinking should have a mutation that returns an empty string "".

[aviggiano]

Interestingly, on a very simple test & microbenchmark, it seems like Medusa wins:

foundry-rs/foundry#6683

Maybe this needs a real benchmark

[0xalpharush]

One consideration is that the stateless example in this PR should be able to shrunk to 1 call consistently
#363

[0xalpharush]

Remove reverts when shrinking crytic/echidna#1250