Remove swarm hash from bytecode before hashing it #105
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packages/cli/src/utils/contracts.js
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| } | ||
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| function removeSwarmHash(bytecode) { | ||
| return bytecode.replace(/a165627a7a72305820.*0029$/, '') |
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would you mind adding a comment to explain this chunk of bytecode?
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Looks good @jcarpanelli! Added a minor comment. Regarding the flag, let's not add optional parameters that we don't yet need: if we reach a point where we need to hash stuff without removing the swarm hash, then we can add it.
And last but not least: please add a unit test for this (even though I'm afraid there was none previously).
packages/cli/src/utils/contracts.js
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| // respects the following structure: 0xa1 0x65 'b' 'z' 'z' 'r' '0' 0x58 0x20 <32 bytes swarm hash> 0x00 0x29 | ||
| // (see https://solidity.readthedocs.io/en/v0.4.24/metadata.html#encoding-of-the-metadata-hash-in-the-bytecode) | ||
| function removeSwarmHash(bytecode) { | ||
| return bytecode.replace(/a165627a7a72305820.*0029$/, '') |
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Let's assert that the swarm hash is indeed 32 bytes. We can replace .* in the regex for [a-fA-F0-9]{64}.
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Also, it'd be interesting to fail if the replace operation does not match anything to replace, in case we stumble upon a contract with a different swarm hash format.
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@spalladino what do you mean by "fail"?
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already discussed it offline.
* Remove swarm hash from bytecode before hashing it * Add a comment explaining the removeSwarmHash fn * Rename removeSwarmHash function and add tests
* Remove swarm hash from bytecode before hashing it * Add a comment explaining the removeSwarmHash fn * Rename removeSwarmHash function and add tests
Fixes #38.
@spalladino should we add an option parameter to the
bytecodeDigestfunction, e.g.,{ removeSwarmHash: true/false }to decide whether to remove it or not?