How to resolve 'Collection Must Be a Unique Master Edition v2' error?

Question

I am trying to perform collection verification using Solana on-chain (Rust) code.

let verify_collection_ix = VerifyCollection {
    metadata: *metadata_account.key,
    collection_authority: *payer_account.key,
    payer: *payer_account.key,
    collection_mint: *collection_mint.key,
    collection: *collection_metadata.key,
    collection_master_edition_account: *collection_master_edition_account.key,
    collection_authority_record: None,
}.instruction();

invoke(
    &verify_collection_ix,
    &[
        metadata_account.clone(),
        payer_account.clone(),
        collection_mint.clone(),
        collection_metadata.clone(),
        collection_master_edition_account.clone(),
        system_program.clone(),
        rent_account.clone(),
        metadata_program.clone(),
    ],
)?;

However, when I try to verify the collection in this way, it fails with the error log below.

  logs: [
'Program 5QV2JKhmKshShindhxERAnpbJ7yKz4Hv7S89dhLHr7cf invoke [1]',
'Program log: Start Program : 5QV2JKhmKshShindhxERAnpbJ7yKz4Hv7S89dhLHr7cf',
'Program log: Verifying collection',
'Program metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s invoke [2]',
'Program log: IX: Verify Collection',
'Program log: Collection Must Be a Unique Master Edition v2',
'Program metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s consumed 26200 of 180043 compute units',
'Program metaqbxxUerdq28cj1RbAWkYQm3ybzjb6a8bt518x1s failed: custom program error: 0x52',

When I verify using the metaplex function on the client, the verification succeeds even in the same situation, but I have no idea what the problem is.

metaplex.nfts().verifyCollection({
mintAddress: nftAddress,
collectionMintAddress: collectionAddress,});

If anyone knows how to solve this problem in Rust code, please help. I'm spending too much time on this one issue.

Answer 1

Check the master_edition address you are passing in. That might be causing it.

To also simplify your work, Metaplex provides CPI IX builders so that you do not have to worry about account management.

VerifyCollectionCpiBuilder::new(&mpl_metadata_program)
            .metadata(&metadata_account)
            .collection_authority(&authority.to_account_info())
            .payer(&authority.clone())
            .collection_mint(&collection_mint)
            .collection(&collection)
            .system_program(&system_program)
            .sysvar_instructions(&sysvar_instructions)
            .invoke()?;

docs.rs reference https://docs.rs/mpl-token-metadata/latest/mpl_token_metadata/instructions/struct.VerifyCollectionV1CpiBuilder.html

Answer 2

It has been confirmed that if the max_supply value is not set to 0 when creating a collection NFT, the 'Collection Must Be a Unique Master Edition v2' error occurs when attempting verification with the collection.

These days, if you use the client function provided by Metaplex, problems like mine will not occur, but I am leaving a solution for those who want to try NFT minting using only Rust functions like me, or for me in the future.