[nkatha23]

Part of braidpool/braidpool#313. Architecture documented in the SV2 integration workflow.

This PR Adds two new crates to the pool-apps workspace:

braidpool-common defines BraidpoolTemplate, a shared type the Braidpool node sends to the SV2 pool. This keeps sv2-apps independent of node internals by providing a clean boundary between the two repositories.

braidpool-template-provider receives BraidpoolTemplate via a tokio::sync::mpsc channel and converts to SV2 TemplateDistribution messages (NewTemplate + SetNewPrevHash). Runs as a sibling task to ipc_template_consumer in the node.

[Copilot]

🟡 Changes recommended

There are confirmed protocol/behavior correctness issues (coinbase value/outputs semantics, header_timestamp=0, and incoming channel close handling) that can lead to invalid SV2 behavior or runaway loops.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds initial scaffolding for Braidpool SV2 integration by introducing a shared template boundary type (braidpool-common) and a template-provider crate that converts those templates into SV2 TemplateDistribution messages.

Changes:

• Extend pool-apps workspace to include braidpool-common and braidpool-template-provider.
• Add braidpool-common::BraidpoolTemplate and initial SV2 message builders / consumer loop.
• Update CI workflow to run on the sv2-integration-braidpool branch.

File summaries

File	Description
pool-apps/Cargo.toml	Adds the two new crates to the pool-apps workspace.
pool-apps/Cargo.lock	Locks new workspace crates and dependency graph changes (e.g. serde/rand features).
pool-apps/braidpool-template-provider/src/sv2_messages.rs	Builds NewTemplate / SetNewPrevHash from BraidpoolTemplate.
pool-apps/braidpool-template-provider/src/lib.rs	Async consumer loop bridging templates to SV2 TemplateDistribution messages.
pool-apps/braidpool-template-provider/src/error.rs	Defines error types used by the provider and message builders.
pool-apps/braidpool-template-provider/Cargo.toml	Declares the new provider crate and dependencies.
pool-apps/braidpool-common/src/template.rs	Defines the shared BraidpoolTemplate boundary type.
pool-apps/braidpool-common/src/lib.rs	Exposes the template module.
pool-apps/braidpool-common/Cargo.toml	Declares the new common crate.
.github/workflows/ci.yaml	Expands CI triggers to include sv2-integration-braidpool branch.

Review details

Suppressed comments (2)

pool-apps/braidpool-template-provider/src/sv2_messages.rs:59

• coinbase_tx_value_remaining is currently set to the sum of all coinbase outputs, while coinbase_tx_outputs serializes all outputs including non-zero payout outputs. In this workspace, SV2 consumers treat coinbase_tx_value_remaining as the value for the payout output they construct (e.g. pool-apps/pool/.../template_distribution_message_handler.rs:50 and miner-apps/jd-client/.../template_message_handler.rs:59), and the reference TP implementation serializes only the required zero-valued outputs (bitcoin-core-sv2/.../v30x/template_data.rs:333-363). Sending full-valued outputs here is likely to produce an invalid coinbase (double-paying) for those consumers.

    let coinbase_tx_value_remaining: u64 = coinbase_tx
        .output
        .iter()
        .map(|o| o.value.to_sat())
        .sum();

pool-apps/braidpool-template-provider/src/lib.rs:123

• The tokio::select! arm pattern-matches only Ok(message) = sv2_incoming_rx.recv(). If the incoming channel closes, recv() resolves to Err immediately and this arm will never match, which can lead to a hot loop and a stuck task. Also, RequestTransactionDataError is sent with let _ = ..., so a closed outgoing channel would silently drop the response.

            Ok(message) = sv2_incoming_rx.recv() => {
                match message {
                    TemplateDistributionOwned::SubmitSolution(_solution) => {
                        debug!("Received SubmitSolution — forwarding to node via bridge");
                        // TODO(sv2-integration): forward to node's block submission channel
                        // This will be wired in PR 4 when the node bridge is added

• Files reviewed: 9/10 changed files
• Comments generated: 4
• Review effort level: Lite

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[Sansh2356]

Code ACK c5b29a6 .

[Sansh2356]

Code ACK c5b29a6, following the flow as discussed .

[Sansh2356]

Resolving conflicts, and lgtm .