linera-io/linera-protocol · error · anyhow::Error

There should be at least one initial validator

Error message

There should be at least one initial validator

What it means

LocalNet, the Rust integration-test harness for a local Linera network, computes its shard topology in instantiate() and requires at least one initial validator; with num_initial_validators == 0 there is no committee to generate, so the harness aborts immediately after make_client().

Source

Thrown at linera-service/src/cli_wrappers/local_net.rs:438

    async fn instantiate(self) -> Result<(Self::Net, ClientWrapper)> {
        let storage_config = self.storage_config_builder.build(self.database).await?;
        let mut net = LocalNet::new(
            self.network,
            self.testing_prng_seed,
            self.namespace,
            self.num_initial_validators,
            self.num_proxies,
            self.num_shards,
            storage_config,
            self.cross_chain_config,
            self.path_provider,
            self.block_exporters,
            self.binary_dir,
            self.export_blocks_to_committee,
            self.block_export_transport,
        );
        let client = net.make_client().await;
        ensure!(
            self.num_initial_validators > 0,
            "There should be at least one initial validator"
        );
        let total_number_shards = self.num_initial_validators * self.num_shards;
        ensure!(
            total_number_shards <= MAX_NUMBER_SHARDS,
            "Total number of shards ({}) exceeds maximum allowed ({})",
            self.num_shards,
            MAX_NUMBER_SHARDS
        );
        net.generate_initial_validator_config().await?;
        client
            .create_genesis_config(
                self.num_other_initial_chains,
                self.initial_amount,
                self.policy_config,
                self.http_request_allow_list
                    .clone()

View on GitHub (pinned to 6c226ddcb3)

Solutions

1. Set at least one initial validator, e.g. `.with_num_initial_validators(4)`, matching your test's committee needs
2. Skip the test when the configured size is 0 instead of instantiating
3. Make the test read the count from the same source as the rest of its configuration to avoid divergent defaults

Example fix

// before
let net = builder.with_num_initial_validators(0).build().instantiate().await?; // ensure fails

// after
let net = builder.with_num_initial_validators(4).build().instantiate().await?;

assert!(
    net_builder.num_initial_validators > 0,
    "LocalNet requires at least one initial validator"
);

When it happens

Trigger: Building a LocalNet whose num_initial_validators is 0 (e.g. `.with_num_initial_validators(0)` or a builder whose field defaults/inputs resolve to 0) and calling instantiate().

Common situations: Parameterized test matrices that iterate committee sizes including zero; refactors that read the validator count from an env var or config defaulting to 0.

Related errors

• Total number of shards ({}) exceeds maximum allowed ({})
• Found issues while querying validators
• Found faulty validators
• Found one or several issue(s) while querying validator {}
• Failed to start node service

AI-assisted analysis of linera-io/linera-protocol@6c226ddcb3 (2026-08-22). Data as JSON: /api/errors/8b811dbdc55b13ca. Report an issue: GitHub.