[Draft] web3 versioned transaction support

[jstarry]

This draft PR will be broken up into smaller PRs but gives a look at what all the versioned transaction classes and APIs look like together

Classes

Naming suggestions welcomed

TransactionMessage

This class should be used to:
- construct new transactions (legacy or v0)
- display not-yet-processed transactions (in wallets)
- display already-processed transactions (in explorers)
- convert compiled messages (legacy or v0) into a more usable form

VersionedTransaction

This class should be used to:
- sign compiled (legacy or v0) messages (by wallets)
- serialize into a wire transaction buffer
- deserialize a wire transaction buffer

MessageV0

This class should be used to:
- serialize into a v0 message buffer for signing
- deserialize a v0 message buffer

MessageAccountKeys

This class won't be used directly by developers but is used internally to wrap static account keys and dynamic account keys loaded from lookup tables

CompiledKeys

This class won't be used directly by developers but is used internally to extract account keys that can be loaded from an address lookup table

[ckamm]

So using the new compilation to build this transaction would work like this?

const transaction = new VersionedTransaction(
    MessageV0.compile({
        payerKey: payer.publicKey,
        instructions: [transferIx],
        recentBlockhash: blockhash,
        addressLookupTableAccounts: [lookupTableAccount],
    })
);

Sounds good to me.

Maybe this test could send a second transaction that was compiled that way? Possibly add a handful of testcases where the MessageV0.compile() output is compared to an expected result?

[jstarry]

Here's a rough guide for how these new classes would be used:

1. App builds transaction for user

const txMessage = new TransactionMessage({
  instructions,
  recentBlockhash,
  payerKey,
});

// if desired, legacy transactions can still be used
const versionedTx = new VersionedTransaction(
  txMessage.compile({version: 'legacy'}),
);

// if lookup tables are needed, v0 is required
const versionedTx = new VersionedTransaction(
  txMessage.compile({
    version: 0,
    addressLookupTableAccounts,
  });
);

// send via wallet for signing
const wallet = WalletAdapter.useWallet();
wallet.sendTransaction(versionedTx, connection);

2. Transaction is received by wallet

const addressLookupTableAccounts = await Promise.all(
  versionedTx.message.addressTableLookups.map((lookup) => {
    return connection.getAddressLookupTable(lookup.tableKey);
  });
);

// Decompile the transaction message to display details to the user
const txMessage = TransactionMessage.decompile({
  message: versionedTx.message,
  addressLookupTableAccounts,
});

// Simulate the transaction (not yet implemented)
await connection.simulateTransaction(versionedTx);

// Sign the transaction
versionedTx.sign([walletKeypair]);

// Send the transaction
await connection.sendRawTransaction(versionedTx);

3. Transaction is fetched by explorer

// Fetch versioned transaction
const transactionResponse = await connection.getTransaction(signature, {
  maxSupportedTransactionVersion: 0,
});

// Decompile the transaction message to display details to the user
const txMessage = TransactionMessage.decompile({
  message: transactionResponse.transaction.message,
  loadedAddresses: transactionResponse.meta.loadedAddresses,
});

[codecov]

Codecov Report

Merging #27213 (5b326b0) into master (e779032) will decrease coverage by 4.1%.
The diff coverage is n/a.

❗ Current head 5b326b0 differs from pull request most recent head 72c6339. Consider uploading reports for the commit 72c6339 to get more accurate results

@@            Coverage Diff            @@
##           master   #27213     +/-   ##
=========================================
- Coverage    76.9%    72.8%   -4.2%     
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  Files          48       54      +6     
  Lines        2505     2835    +330     
  Branches      355      387     +32     
=========================================
+ Hits         1927     2064    +137     
- Misses        448      638    +190     
- Partials      130      133      +3     

[mergify]

⚠️ The sha of the head commit of this PR conflicts with #27526. Mergify cannot evaluate rules on this PR. ⚠️