NPE when making a JSON/RPC call too early that requires the transaction pool to be initialized

[matthew1001]

Description

I start a new Besu node and before it has synced I submit a new transaction. This requires the nonce for the sender to be determined, which hits the following NPE because the transaction pool hasn't been initialized yet:

java.lang.NullPointerException: Cannot invoke "org.hyperledger.besu.ethereum.eth.transactions.PendingTransactions.getNextNonceForSender(org.hyperledger.besu.datatypes.Address)" because "this.pendingTransactions" is null
        at org.hyperledger.besu.ethereum.eth.transactions.TransactionPool.getNextNonceForSender(TransactionPool.java:539)
        at org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.EthGetTransactionCount.pendingResult(EthGetTransactionCount.java:60)
        at org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.AbstractBlockParameterOrBlockHashMethod.handleParamTypes(AbstractBlockParameterOrBlockHashMethod.java:100)
        at org.hyperledger.besu.ethereum.api.jsonrpc.internal.methods.AbstractBlockParameterOrBlockHashMethod.response(AbstractBlockParameterOrBlockHashMethod.java:151)
        at org.hyperledger.besu.ethereum.api.jsonrpc.execution.BaseJsonRpcProcessor.process(BaseJsonRpcProcessor.java:44)
        at org.hyperledger.besu.ethereum.api.jsonrpc.execution.TracedJsonRpcProcessor.process(TracedJsonRpcProcessor.java:41)
        at org.hyperledger.besu.ethereum.api.jsonrpc.execution.TimedJsonRpcProcessor.process(TimedJsonRpcProcessor.java:45)
        at org.hyperledger.besu.ethereum.api.jsonrpc.execution.JsonRpcExecutor.execute(JsonRpcExecutor.java:92)
        at org.hyperledger.besu.ethereum.api.handlers.AbstractJsonRpcExecutor.executeRequest(AbstractJsonRpcExecutor.java:87)
        at org.hyperledger.besu.ethereum.api.handlers.JsonRpcObjectExecutor.execute(JsonRpcObjectExecutor.java:57)
        at org.hyperledger.besu.ethereum.api.handlers.JsonRpcExecutorHandler.lambda$handler$0(JsonRpcExecutorHandler.java:57)
        at java.base/java.util.Optional.ifPresentOrElse(Optional.java:196)
        at org.hyperledger.besu.ethereum.api.handlers.JsonRpcExecutorHandler.lambda$handler$2(JsonRpcExecutorHandler.java:54)
        at io.vertx.ext.web.impl.BlockingHandlerDecorator.lambda$handle$0(BlockingHandlerDecorator.java:48)
        at io.vertx.core.impl.ContextImpl.lambda$executeBlocking$1(ContextImpl.java:190)
        at io.vertx.core.impl.ContextInternal.dispatch(ContextInternal.java:276)
        at io.vertx.core.impl.ContextImpl.lambda$internalExecuteBlocking$2(ContextImpl.java:209)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.base/java.lang.Thread.run(Thread.java:833)
^C2024-04-02 16:40:43.003+01:00 | BesuCommand-Shutdown-Hook |

Steps to Reproduce (Bug)

1. Run besu --genesis-file=genesis.json --profile=enterprise --data-storage-format=FOREST --data-path=./data --rpc-http-enabled
2. Before the node has synced and started mining blocks, submit a new transaction

Expected behavior:
No NPE. I think the correct behaviour is either a) a suitable error code being returned to the JSON/RPC call or b) the transaction pool accepting the transaction and it being mined when the node has synced.

Actual behavior:
NPE shown above

Frequency:
Always

Versions (Add all that apply)

• Software version: besu/v24.4-develop-cf5e3dae98/osx-aarch_64/openjdk-java-17

[matthew1001]

I think this may be related to #6302 @fab-10 ?

[fab-10]

yes i think so, it should return an error response saying the txpool is disabled and not throwing an exception, so it is definitely a bug

[Gabriel-Trintinalia]

@fab-10 do you think initiating pendingTransactions with new DisabledPendingTransactions would be enough here?

[fab-10]

yes, it works, and while verifying you suggestion, I just made the fix and added some tests :)