fix: ensure witness size is power of two

[DeVikingMark]

Fixes #287

Added check to ensure witness size is power of two in CRR1CSProof::prove() function to prevent potential index out of bounds error when reading from empty vector.

Changes made:

• Added assertion to check if witness size is power of two
• Added descriptive error message for better debugging

This prevents the issue where reading index of zero from an empty vector could occur if the witness size is not a power of two.

[sjudson]

@DeVikingMark thanks for taking a pass at this. Looks like tests are failing at the moment, however.

[DeVikingMark]

@DeVikingMark thanks for taking a pass at this. Looks like tests are failing at the moment, however.

by chance, do these changes seem alright to you?

[sjudson]

Thanks for this, looks good to me.

[sjudson]

@DeVikingMark looks like it needs some formatting + clippy fixes.

[sjudson]

Withdrawing acceptance till pending tests are fixed, but overall design still looks good.

[sjudson]

@DeVikingMark what is the reason for removing an existing test?

Also, please run cargo fmt and cargo clippy --all-targets --all-features, since those lints keep failing.

[DeVikingMark]

Hey Samuel, I've made a change:

• Fixed the clippy warning in vm/src/eval.rs by replacing map_or with is_some_and

Note: The cargo clippy command shows errors related to the pprof library on Windows, but these are unrelated to my code changes.

[sjudson]

@DeVikingMark can you answer:

what is the reason for removing an existing test?

[DeVikingMark]

@DeVikingMark can you answer:

what is the reason for removing an existing test?

@sjudson I've deleted them by accident, and forgot to add it, sorry that's my fault

I've made some updates, probably now everything should be fine, I'll be waiting for tests to be completed

[sjudson]

Almost there, but there is still some inconsistent indentation.

[sjudson]

LGTM pending tests passing...

[sjudson]

@DeVikingMar clippy + fmt lints are still failing

[DeVikingMark]

@sjudson Could it be that these errors are not related to my changes and were here before my intervention?