How to deserialize a Magic Link's versioned transaction?

Question

Getting the following error when trying to send a signed transaction with Magic Link.

WalletSignTransactionError: Versioned messages must be deserialized with VersionedMessage.deserialize()

Magic's signTransaction method

  async signTransaction<
    T extends TransactionOrVersionedTransaction<
      this['supportedTransactionVersions']
    >,
  >(transaction: T): Promise<T> {
    try {
      if (!this._user) throw new WalletNotConnectedError();
      try {
        const config = { requireAllSignatures: false, verifySignatures: true };
        const signedTransaction = await this._magic?.solana.signTransaction(
          transaction,
          config,
        );

        const msg = Buffer.from(
          signedTransaction?.rawTransaction as string,
          'base64',
        );
        return Transaction.from(msg) as T;
      } catch (error: any) {
        throw new WalletSignTransactionError(error?.message, error);
      }
    } catch (error: any) {
      this.emit('error', error);
      throw error;
    }
  }

Doc reference: https://magic.link/docs/blockchains/featured-chains/solana#sign-and-send-transaction

Solution: Update @magic-ext/solana to latest version and handle for versioned txn

  async signTransaction<
    T extends TransactionOrVersionedTransaction<
      this['supportedTransactionVersions']
    >,
  >(transaction: T): Promise<T> {
    try {
      if (!this._user) throw new WalletNotConnectedError();
      try {
        const config = { requireAllSignatures: false, verifySignatures: true };
        const signedTransaction = await this._magic?.solana.signTransaction(
          transaction,
          config,
        );

        let msg: Uint8Array;
        let rawTx: unknown = signedTransaction?.rawTransaction;

        if (rawTx instanceof Uint8Array) {
          msg = rawTx;
        } else if (typeof rawTx === 'string') {
          msg = base64.serialize(rawTx);
        } else {
          throw new Error(`Raw transaction is not a buffer or string`);
        }

        try {
          return Transaction.from(msg) as T;
        } catch {
          return VersionedTransaction.deserialize(msg) as T;
        }
      } catch (error: any) {
        throw new WalletSignTransactionError(error?.message, error);
      }
    } catch (error: any) {
      this.emit('error', error);
      throw error;
    }
  }

Answer 1

That error is probably coming from web3js: https://github.com/solana-labs/solana-web3.js/blob/f025b33f8f463b640807772e5f3b5e21f54deae9/packages/library-legacy/src/message/legacy.ts#L277

Specifically it's thrown by the Message.from function when you pass it a versioned transaction. That is called by Transaction.from: https://github.com/solana-labs/solana-web3.js/blob/f025b33f8f463b640807772e5f3b5e21f54deae9/packages/library-legacy/src/transaction/legacy.ts#L912

It's also possible that something in this._magic?.solana.signTransaction is calling it, so you might want to verify that. An easy way would be to put a log statement after signedTransaction, if that log prints then you know that line is not responsible for the error. If that holds, then this._magic?.solana.signTransaction is returning a versioned transaction. You can read more about versioned transactions in the docs: https://solana.com/docs/core/transactions/versions

If that's the case then you'll need to switch to using VersionedTransaction.deserialize: https://solana-labs.github.io/solana-web3.js/classes/VersionedTransaction.html#deserialize. This supports both legacy (not versioned) and versioned transactions and will avoid the error.

Note that you'll need to convert your base64 string to a Uint8Array to use VersionedTransaction.deserialize. There are a number of ways to do this, but our recommendation in the new web3js will be to use @solana/codecs-strings. You can install this alongside the existing web3js, but currently need the experimental tag. npm install @solana/codecs-strings@experimental

Then you can do this:

// import { getBase64Encoder } from '@solana/codecs-strings; 

// convert base64 string to Uint8Array
const msg = getBase64Encoder().encode(signedTransaction?.rawTransaction as string);
return VersionedTransaction.deserialize(msg);

Example sandbox showing this: https://stackblitz.com/edit/stackblitz-starters-mpd3gj?file=index.mjs