Simple OP_EQUAL script (Script evaluated without error but finished with a false/empty top stack element)

Question

I'm testing a P2TR script path spend.

The script tree contains a single script leaf with the following script:

hex: 5887
asm: OP_8 OP_EQUAL

The witness spending this output then consists of the following:

58 5887 <control block>

So the complete script should execute like this:

hex: 585887
asm: OP_8 OP_8 OP_EQUAL

However, when I try to send the transaction in to the network I get the following error:

error code: -26
error message:
mandatory-script-verify-flag-failed (Script evaluated without error but finished with a false/empty top stack element)

Is this to be expected? Or might there be something else wrong with my witness structure (or the original script)?

Answer 1

The witness only contains data pushes, unlike the scriptSig. Here the Script interpreter compares 0x58 and 8 and pushes 0 on the stack. Hence the error:

Script evaluated without error but finished with a false/empty top stack element