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Fix "ParserError: Multiple SPDX license identifiers found in source file"

See original GitHub issue

When you have two contracts, one depending form another, since solc v0.6.8, all of them should contain the SPDX license.

When I try truffle run verify it would yield the error

General exception occured when attempting to insert record 
Failed to verify 1 contract(s): <name of your contact>

If I do manually npx truffle-flattener and upload it for etherscan I get the more detailed error:

Error! Unable to generate Contract ByteCode and ABI (General Exception, unable to get compiled [bytecode])
...
myc: ParserError: Multiple SPDX license identifiers found in source file. Use "AND" or "OR" to combine multiple licenses. Please see https://spdx.org for more information.

when I remove the duplicates of // SPDX-License-Identifier from contact before upload to etherscan this error disappears. So I assume that corresponding fix is needed.

Issue Analytics

State:
Created 3 years ago
Comments:13 (6 by maintainers)

Top GitHub Comments

1reaction

rkaliscommented, Feb 16, 2021

Hmm interesting, thanks for looking into it @Enigmatic331!

I’m guessing that the “double escape” is due to an error on my side when trying to output the Input JSON manually, since for API usage, the JSON content does gets stringified (as expected).

So then manual verification for this contract did work, but the API returns “General exception occured when attempting to insert record”. Do you have any indication for what this API response means on the Etherscan side?

1reaction

Enigmatic331commented, Feb 15, 2021

Hey Rosco! Thanks for pinging.

Hmm. I popped open one of the files and had a quick look. Seems like they’re JSON escaped twice? I unescaped them once and cleaned the formatting it a little (just so it’s easier on my eyes), then reattempted verification through Etherscan: https://rinkeby.etherscan.io/address/0x71694eE1B3D95885FF94202f631B942462fD6B08#code

The file I used as attached (rename the file as .json): 2.txt

The “double escape” is causing issues with solc compilation when I tried directly with solc.exe (hint: if Etherscan shows no compiled bytecode during verification, it means solc could not compile it at all) - So removing one layer of escape should be all it was needed.

@lebed2045 - I see you Alex of StableUnit 😄