enforce deployment limits on beacon blocks

[mohammadfawaz]

Motivation

Devnode beacon blocks skip proof verification, but they must enforce deployment limits. snarkVM 4.9.0 does not apply the block-wide spend and synthesis limits to beacon blocks. This can let an invalid deployment enter a development ledger.

This change keeps the released snarkVM 4.9.0 dependency. The devnode calculates and applies the beacon limits before it advances a block. Placeholder proofs and the existing dev_skip_checks behavior stay active.

Changes

• Apply the beacon spend limit from consensus V16.
• Apply the beacon synthesis limit from consensus V18.
• Preserve transaction order when a limit or snarkVM aborts a candidate.
• Return an error and do not create a block after an automatic-mode abort.
• In manual mode, remove aborted transactions and keep valid transactions for a retry.

Test Plan

• Run cargo fmt --all -- --check.
• Run cargo test --locked.
• Confirm that all 6 unit tests and all 6 integration tests pass.
• Confirm that a real deployment cost from snarkVM crosses the beacon spend ceiling and aborts the excess candidate.
• Confirm that raw snarkVM 4.9.0 accepts deployments that exceed the block synthesis limit.
• Confirm that the devnode rejects the over-limit deployments.
• Confirm that a later valid deployment with the same public fee payer stays valid.
• Confirm that an oversized automatic deployment returns 422 on /v2 and does not change the ledger height.
• Confirm that manual block creation returns 422, removes the aborted deployment, keeps valid deployments, and permits a successful retry.

Related PRs

• Enforce block spend and synthesis limits for beacon blocks snarkVM#3350

[Copilot]

Pull request overview

This PR updates the devnode’s REST block-minting path to proactively enforce beacon-block deployment limits (spend from consensus V16 and synthesis from consensus V18) that snarkVM 4.9.0 does not apply to beacon blocks, while preserving the existing dev_skip_checks behavior.

Changes:

• Adds limit calculation + transaction filtering for beacon-block preparation, and wires it into both auto and manual block creation flows.
• Ensures transaction order is preserved across aborts, and changes behavior so aborted candidates return an error and do not produce a block (with manual mode retaining non-aborted buffered transactions for retry).
• Expands unit tests and REST API docs to cover the new behavior and error semantics.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/start.rs	Adds a guard test asserting the latest TEST_CONSENSUS_VERSION_HEIGHTS entry aligns with V18 expectations.
src/rest/routes.rs	Implements beacon spend/synthesis limit enforcement during block preparation and updates auto/manual block creation behavior; adds extensive tests.
docs/rest-api.md	Documents new 422 behavior and limit enforcement semantics for /transaction/broadcast and /block/create.

Suppressed comments (1)

src/rest/routes.rs:1124

• This test mirrors the same min_certificates computation as beacon_block_limits, but it currently uses ceil(max_certificates/3) * 2, which overestimates a 2/3 quorum for some max_certificates values. Update it to match the corrected ceil(2*max_certificates/3) formula so the expected limits stay aligned with the implementation.

        let min_certificates = max_certificates.saturating_add(2).saturating_div(3).saturating_mul(2);

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