Add txpool_contentFrom JSON-RPC method

[fab-10]

Summary

Implements the txpool_contentFrom JSON-RPC method as defined in the execution-apis spec.

Given a sender address, returns the pending (executable) and queued (non-executable) transactions for that address, split by nonce continuity from the account's current on-chain nonce.

Example response:

{
  "pending": {
    "0": { "nonce": "0x0", "from": "0x123...", ... },
    "1": { "nonce": "0x1", "from": "0x123...", ... }
  },
  "queued": {
    "3": { "nonce": "0x3", "from": "0x123...", ... }
  }
}

Changes

• Add TX_POOL_CONTENT_FROM to RpcMethod enum
• Add TxPoolContentFrom handler and TransactionPoolContentFromResult result type
• Register the method in TxPoolJsonRpcMethods
• Add getPendingTransactionsForSender(Address) and getCurrentNonceForSender(Address) to the PendingTransactions interface with implementations in LayeredPendingTransactions, AbstractPendingTransactionsSorter, and DisabledPendingTransactions

Test plan

• Unit tests in TxPoolContentFromTest cover:
  • Empty transaction pool for sender
  • All transactions executable (no nonce gap) → all pending
  • All transactions queued (gap at start)
  • Mixed pending + queued split
  • Account with no on-chain state (nonce defaults to 0)
  • Account with non-zero current nonce
  • Missing address parameter returns InvalidJsonRpcParameters

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Implements the txpool_contentFrom JSON-RPC method to return pending vs queued transactions for a given sender, split by nonce continuity from the sender’s on-chain nonce.

Changes:

• Added txpool_contentFrom to the JSON-RPC method registry and RpcMethod enum.
• Extended the transaction pool APIs to retrieve a sender’s transactions and current nonce.
• Added result/handler types plus a new unit test suite validating nonce-gap splitting behavior.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/sorter/PendingTransactionsForSender.java	Adds current-nonce accessor and adjusts synchronization while reading sender txs
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/sorter/AbstractPendingTransactionsSorter.java	Implements new per-sender pending tx and current nonce retrieval methods
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/layered/LayeredPendingTransactions.java	Plumbs per-sender pending tx and current nonce through layered pool implementation
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/TransactionPool.java	Exposes per-sender pending tx list and current nonce from the pool
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/PendingTransactions.java	Extends interface with per-sender tx retrieval and current-nonce lookup
ethereum/eth/src/main/java/org/hyperledger/besu/ethereum/eth/transactions/DisabledPendingTransactions.java	Provides empty implementations for new interface methods
ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/TxPoolContentFromTest.java	Adds unit tests for txpool_contentFrom behavior
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/methods/TxPoolJsonRpcMethods.java	Registers new TxPoolContentFrom RPC method
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/results/TransactionPoolContentFromResult.java	Adds JSON result type for pending/queued-by-nonce response
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/methods/TxPoolContentFrom.java	Implements txpool_contentFrom handler and nonce-gap splitting logic
ethereum/api/src/main/java/org/hyperledger/besu/ethereum/api/jsonrpc/RpcMethod.java	Adds TX_POOL_CONTENT_FROM enum entry

[macfarla]

couple of nits, otherwise LGTM