Local Node Validation

Validates that contracts working in MockChain also work against a real Miden node. This catches known MockChain/live-node behavior gaps before they become harder to debug in production or the frontend.

Why This Matters

MockChain simplifies execution in ways that hide real-world failures:

1. No automatic block production -- MockChain requires explicit prove_next_block(). A live node produces blocks on its own schedule.
2. No network transport -- MockChain does not simulate the network transaction builder that handles network notes.
3. No RPC latency or timeouts -- MockChain executes locally and instantly. Live nodes have gRPC round-trips with configurable timeouts.
4. No version/genesis validation -- MockChain skips the Accept header version check that live nodes enforce.
5. Account update block numbers not tracked -- MockChain returns chain tip instead of actual update block number.
6. No mempool or batching -- MockChain does not simulate transaction queuing, batch formation, or block inclusion delays.
7. Genesis hash is cached in the client store -- after the first sync, the client persists the network's genesis commitment in its SQLite store (default path store.sqlite3 per integration/src/helpers.rs; local-store.sqlite3 for the local-validation variant introduced in Step 2) and ships it on every Accept header. Switching networks (local node to testnet, or vice versa) without wiping the active store fails with accept header validation failed.
8. NoteTag(0) notes are not delivered by default subscriptions -- live nodes filter SyncNotes responses by the tag list each client has subscribed to. NoteTag::new(0) has all-zero routing bits, so the default account-derived subscription that add_account registers (NoteTagRecord::with_account_source(NoteTag::with_account_target(id), id)) does not match it. Such notes still exist on-chain and remain queryable, but a client only receives them during sync if it explicitly tracks tag 0 via Client::add_note_tag(...). MockChain bypasses sync filtering and surfaces these notes anyway, hiding the gap until live validation. Prefer NoteTag::with_account_target(account_id), a use-case tag constructor, or an explicit add_note_tag subscription when notes must reach the recipient via sync.

Prerequisites

• MockChain integration tests pass: cargo test -p integration --release
• miden-node installed and version-matched with the client. Check the miden-client version in integration/Cargo.toml; the node binary must be on the same minor release. cargo install miden-node --locked may pin an older published crate; if so, install from source: cargo install miden-node --locked --git https://github.com/0xMiden/miden-node --tag v<version>. midenup manages matched toolchains.
• Working integration binary exists in integration/src/bin/

Step 1: Clean State and Start Local Node

Every node session must start from clean state. Stale store files and keystore directories cause conflicts, deserialization errors, and misleading test results. Always wipe before starting.

# 1. Wipe all state from previous runs
rm -rf local-node-data/ local-keystore/ local-store.sqlite3

# 2. Bootstrap fresh node
mkdir -p local-node-data
miden-node bundled bootstrap \
  --data-directory local-node-data \
  --accounts-directory .

# 3. Start node (keep running in separate terminal)
miden-node bundled start \
  --data-directory local-node-data \
  --rpc.url http://0.0.0.0:57291

This clean-start sequence is mandatory every time. Do not attempt to reuse state from a previous session.

Step 2: Adapt helpers.rs for Localhost

In integration/src/helpers.rs, add a setup_local_client() alongside the existing setup_client():

pub async fn setup_local_client() -> Result<ClientSetup> {
    let endpoint = Endpoint::new("http".into(), "localhost".into(), Some(57291));
    let timeout_ms = 10_000;
    let rpc_client = Arc::new(GrpcClient::new(&endpoint, timeout_ms));

    let keystore_path = std::path::PathBuf::from("../local-keystore");
    let keystore = Arc::new(FilesystemKeyStore::new(keystore_path)
        .context("Failed to initialize local keystore")?);

    let store_path = std::path::PathBuf::from("../local-store.sqlite3");

    let client = ClientBuilder::new()
        .rpc(rpc_client)
        .sqlite_store(store_path)
        .authenticator(keystore.clone())
        .in_debug_mode(true.into())
        .build()
        .await
        .context("Failed to build local Miden client")?;

    Ok(ClientSetup { client, keystore })
}

Use separate paths (local-keystore/, local-store.sqlite3) to avoid contaminating testnet state.

Step 3: Create Local Validation Binary

Create integration/src/bin/validate_local.rs mirroring the existing testnet binary (increment_count.rs) but using setup_local_client().

The binary must:

1. Call setup_local_client() instead of setup_client()
2. Sync state: client.sync_state().await?
3. Build contracts (same as existing binary)
4. Create accounts, create notes, submit transactions
5. Sync again after each transaction submission
6. Wait for transaction inclusion (poll sync_state until account state updates)
7. Verify final state matches MockChain test expectations
8. Print clear pass/fail for each verification step

Key differences from testnet binary:

• Localhost endpoint (port 57291)
• Separate keystore and store paths
• Must handle block production timing (sync + wait between submissions)

Account deployment: Client::add_account() only writes the account to the local client store; it does not register the account on-chain. To make a public or network account discoverable by other clients, submit a transaction involving the account (typically the account's first transaction). Until that transaction is included in a block, get_account_details(id) from any other client returns "not found".

Step 4: Run and Verify

Ensure clean client state before running (the node should already be clean from Step 1):

rm -rf local-keystore/ local-store.sqlite3
cargo run --bin validate_local --release

Verification Checklist

• sync_state() succeeds (node reachable, no version mismatch)
• Account creation succeeds (account appears after sync)
• Note publication succeeds (transaction accepted by node)
• Note consumption succeeds (state transitions as expected)
• Final state matches MockChain test expectations
• No RPC timeout errors
• Node logs show no errors

Step 5: Inspect Node Logs

Run the node with verbose logging:

RUST_LOG=info miden-node bundled start \
  --data-directory local-node-data \
  --rpc.url http://0.0.0.0:57291

Look for:

• Transaction acceptance/rejection messages
• Block production confirmations
• Error or warning lines

Troubleshooting

Symptom	Cause	Fix
Unavailable RPC error	Node not running or wrong port	Start node, verify port 57291
accept header validation failed after switching networks	Client store cached the genesis commitment from a different network	Delete the active client store (store.sqlite3 by default; local-store.sqlite3 for local validation) and re-sync
Version mismatch error	Node binary lags client crate (cargo install miden-node may pin an older published crate)	Reinstall to match miden-client from integration/Cargo.toml: cargo install miden-node --locked --git https://github.com/0xMiden/miden-node --tag v<version>, or use midenup
Vite or proxy returns 404 on RPC calls from frontend	Proxy targets the wrong path prefix	gRPC paths are /rpc.Api/<method> (e.g. /rpc.Api/Status, /rpc.Api/SyncNotes, /rpc.Api/GetAccount); forward the /rpc.Api prefix in the proxy config
Transaction rejected	Invalid proof or state	Check contract code, reset node data, try again
Account not found after add_account()	add_account() is local-only; it does not register the account on-chain	Submit a transaction involving the account to deploy it on-chain, then sync_state()
Store errors or deserialization failures	Stale state from a previous session, or cached genesis from a different network	Wipe everything: rm -rf local-node-data/ local-keystore/ local-store.sqlite3 and re-bootstrap
Block not produced	Node produces blocks when transactions arrive	Submit a transaction; check --block-producer.block-interval setting

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Source: 0xMiden/compiler — distributed by TomeVault.