SIMD-0192: Relax Transaction Constraints - Account Resolution

proposals/0192-transaction_account_resolution.md

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+---
+simd: '0192'
+title: Relax Transaction Account Resolution
+authors:
+  - Andrew Fitzgerald (Anza)
+category: Standard
+type: Core
+status: Review
+created: 2024-11-06
+feature:
+supersedes:
+superseded-by:
+extends:
+---
+
+## Summary
+
+This proposal aims to relax certain transaction errors related to the account
+keys used in  a transaction, from protocol violations to runtime errors.
+
+## Motivation
+
+The current transaction constraints are overly restrictive and add complexity
+to the protocol. Specifically these constraints require that account-state
+in order to validate a block due to lookup tables. This account-state
+dependence makes both block-production and block-validation more complex than
+necessary.
+
+## New Terminology
+
+These terms are used elsewhere, but are defined here for clarity:
+
+- Protocol Violating Transaction Error: A transaction error that violates the
+  protocol. This class of errors must result in the entire block being rejected
+  by the network.
+- Runtime Transaction Error: A transaction error that results in a failed
+  transaction, and may be included in the block. These transactions still
+  incur transaction fees, and nonce advancements.
+
+## Detailed Design
+
+The current protocol requires that the the account keys used in a transaction:
+
+1. Contain no duplicate account keys,
+2. Have no more than 64 account keys,
+    - The limit is subject to change to 128 with the activation of
+      `9LZdXeKGeBV6hRLdxS1rHbHoEUsKqesCC2ZAPTPKJAbK`.
+3. All address lookup tables must be resolvable:
+    - The address lookup table account must exist.
+    - The address lookup table account must be owned by the address lookup
+      table program: `AddressLookupTab1e1111111111111111111111111`
+    - The address lookup table account data must be deserializable into
+      `AddressLookupTable` as defined in `solana-sdk`.
+    - All account table indices specified in the transaction must be less than
+      the number of active addresses in the address lookup table.
+
+This proposal seeks to relax these constraints from protocol violation errors
+to runtime errors.
+This means that transactions that break any of these constraints may be
+included in a block, if they are otherwise valid.
+Such transactions do not need to attempt any further loading or execution; they
+need only to pay fees and advance the nonce.
+Such transactions should have transaction costs for block-limits applied only
+to the fee-payer and nonce accounts, since exucution will not even be
+attempted.
+
+## Alternatives Considered
+
+- Do nothing
+  - This is the simplest option, as we could leave the protocol as is.
+  However, this leaves the protocol more complex than it needs to be.
+- Relax additional constraints:
+  - SIMD-0082 sought to relax additional constraints, but has not been
+    accepted. This proposal is a subset of SIMD-0082, intended to make the
+    review process simpler and faster. Therefore, we have decided to keep
+    this proposal focused specifically on certain loading failures.
+
+## Impact
+
+- Transactions that would previously have been dropped with a protocol
+  violation error can now be included and will be charged fees.
+  - Users must be more careful when constructing transactions to ensure the
+    account keys requested are valid.
+
+## Security Considerations
+
+None
+
+## Drawbacks
+
+- Users must be more careful about what they sign, as they will be charged fees
+  for transactions that are included in a block, even if they are not executed.
+- This will likely break a lot of tooling, such as explorers, which may expect
+  all transactions to attempt execution.
+
+## Backwards Compatibility
+
+This proposal is backwards compatible with the current protocol, since it only
+relaxes constraints, and does not add any new constraints. All previously valid
+blocks would still be valid. However, new blocks may not be valid under the old
+protocol.