failed call mmr_generateProof on rococo testnet

[DaviRain-Su]

I use this command can get data.

echo '{"id":1,"jsonrpc":"2.0","method":"mmr_generateProof","params":[[4007966,4007967,4007968]]}' |  websocat -n1 -B 99999999 wss://rococo-rpc.polkadot.io | jq
{
  "jsonrpc": "2.0",
  "result": {
    "blockHash": "0x0da92932a52bd659ca02d601d77b184e65158f6689291a07a228a9eb8195d56a",
    "leaves": "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",
    "proof": "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"
  },
  "id": 1
}

but I used subxt, I cannot get successful response. here, is example call code.

 // test mmr_generateProof
    let method = "mmr_generateProof";
    // let block_numner: Vec<BlockNumber> = vec![0u32.into(),1u32.into(), 2u32.into()];
    let block_numner: Vec<BlockNumber> = vec![4007966u32.into(),4007967u32.into(),4007968u32.into()];
    // let block_numner: Vec<BlockNumber> = vec![30u64.into()];
    let best_known_block_number = Option::<BlockNumber>::None;
    let at = Option::<sp_core::H256>::None;
    let params = rpc_params![block_numner, best_known_block_number, at];
    let result: LeavesProof<sp_core::H256> = api.rpc().request(method, params).await?;
    println!("mmr_generateProof is {:?}", result);

and example git repo: https://github.com/DaviRain-Su/example-subxt

rococo should report this error:

panicked at 'Bad input data provided to generate_proof: Codec error', /Users/lisagunn/polkadot/runtime/rococo/src/lib.rs:963:1
2023-02-18 16:46:08 💤 Idle (1 peers), best: #419 (0xab71…a534), finalized #416 (0xad19…b62a), ⬇ 0.5kiB/s ⬆ 0.3kiB/s

[niklasad1]

Hey,

Can you run the example with RUST_LOG="jsonrpsee=trace"?
Also to have identical JSON-RPC omit best_known_block_number and at from RPC call i.e,

let params = rpc_params![block_numner];

but yeah not sure what's happening here

[DaviRain-Su]

Hey,

Can you run the example with RUST_LOG="jsonrpsee=trace"? Also to have identical JSON-RPC omit best_known_block_number and at from RPC call i.e,

let params = rpc_params![block_numner];

but yeah not sure what's happening here

have been try, also have problem.

2023-02-18T15:45:37.246320Z TRACE method_call{method="mmr_generateProof"}: jsonrpsee_core::tracing: send="{\"jsonrpc\":\"2.0\",\"id\":10,\"method\":\"mmr_generateProof\",\"params\":[[0,1,2]]}"
2023-02-18T15:45:37.246363Z TRACE jsonrpsee_client_transport::ws: send: {"jsonrpc":"2.0","id":10,"method":"mmr_generateProof","params":[[0,1,2]]}
2023-02-18T15:45:37.248076Z DEBUG jsonrpsee_core::client::async_client: [backend]: Client dropped
Error: Rpc(ClientError(Call(Custom(ErrorObject { code: ServerError(8000), message: "Runtime trapped", data: Some(RawValue("Application(Execution(AbortedDueToTrap(MessageWithBacktrace { message: \"wasm trap: wasm `unreachable` instruction executed\", backtrace: Some(Backtrace { backtrace_string: \"\\n    0: 0x3297a0 - <unknown>!rust_begin_unwind\\n    1: 0x5659 - <unknown>!core::panicking::panic_fmt::hd6942e22a1490f82\\n    2: 0x1f3c08 - <unknown>!MmrApi_generate_proof\\n\" }) })))")) }))))

on rococo test occur this

2023-02-18 23:45:37 Accepting new connection 1/100
2023-02-18 23:45:37 panicked at 'Bad input data provided to generate_proof: Codec error', /Users/lisagunn/polkadot/runtime/rococo/src/lib.rs:963:1
2023-02-18 23:45:37 💤 Idle (1 peers), best: #15 (0xe748…9584), finalized #12 (0xb835…68c5), ⬇ 0.6kiB/s ⬆ 0.3kiB/s

[niklasad1]

This is really just an incorrect use of the runtime API/MMR RPC in substrate and not a subxt issue.

Sorry if I lead down a incorrect path. It looks like you are using it wrong, for historical state you have to provide a best block according to https://github.com/paritytech/substrate/blob/master/primitives/merkle-mountain-range/src/lib.rs#L432-#L438.

Try this instead:

let block_nums: Vec<BlockNumber> = vec![0u32.into(),1u32.into(), 2u32.into()];
let best_block = Some(3);
let params = rpc_params![block_nums, best_block];

If ☝️ doesn't work then I would regard it as substrate/rococo issue and please move/open a new issue in substrate.

[DaviRain-Su]

If ☝️ doesn't work then I would regard it as substrate/rococo issue and please move/open a new issue in substrate.

Yet, It also don't work.

[jsdw]

Offhand this sounds like a Substrate issue/thing then and not a Subxt one, so any objections if I close this?

[niklasad1]

Let's close this, apparently it has been around for a while paritytech/substrate#12864