Fuzzer: Do not return 0 from upTo when input is finished#8653
Merged
kripken merged 2 commits intoWebAssembly:mainfrom Apr 28, 2026
Merged
Fuzzer: Do not return 0 from upTo when input is finished#8653kripken merged 2 commits intoWebAssembly:mainfrom
kripken merged 2 commits intoWebAssembly:mainfrom
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This was added to simplify our output when the random data is small - it
makes us pick simpler options, which helps a little there - but the downsides
are large, so revert this part.
Specifically, we consume all the random input to generate functions. We
then do a small amount of random usage at the end, things like export
mutation. To handle that, we keep returning random values even after
the random input is consumed (using some xor-ing to try to keep things
random). But if we just return 0 at that point, we are missing out on a lot of
variety.
This was added in #7832. All the rest of that PR makes sense - we can
check for the end of the random data and do simpler things - but we
should not do the simplest possible thing in the generic
upTomethodwhich would simplify everything, even things we don't want to.