fix: only assign aggregator role to node 1 in simtest#642
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anshalshukla merged 1 commit intomainfrom Mar 8, 2026
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When running `zig build simtest`, all three nodes were initialized with `.is_aggregator = beamcmd.@"is-aggregator"`, causing all of them to act as aggregators when the --is-aggregator flag is set. Per the spec, only one aggregator should exist per subnet. Fix: hardcode `is_aggregator = false` for nodes 2 and 3. Only node 1 (the primary node) inherits the CLI flag. Fixes #641
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GrapeBaBa
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Mar 8, 2026
anshalshukla
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Mar 8, 2026
zclawz
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Mar 9, 2026
The mock network's publish() and onGossip() were calling gossipHandler.onGossip(..., scheduleOnLoop=true), which defers gossip delivery via a 1ms event-loop timer. This caused a race condition in the simtest: with a single aggregator (node 1), attestations from nodes 2 and 3 were scheduled for async delivery but not yet in node 1's gossip_signatures when it aggregated at interval 2. Result: only 1/3 validator participation, enough for justification but not finalization. The scheduleOnLoop flag exists for the real libp2p network (where handlers can't be called synchronously from the network thread). In the mock, all nodes share the same event loop and gossip should be delivered synchronously to correctly simulate instant peer propagation. Fix: pass scheduleOnLoop=false in mock.zig's publish() and onGossip(). Fixes flaky simtest introduced after #642.
zclawz
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Mar 10, 2026
Root cause of finalization deadlock with 2 active validators: 1. Block processing calls onAttestation(is_from_block=true), which clears latestNew for every validator whose attestation is in the block. 2. updateSafeTargetUnlocked uses computeFCHeadUnlocked(from_known=false) which reads only latestNew. 3. After a block is processed at interval 0, the proposer skips gossip attestation at interval 1 — so only 1 validator fills latestNew. 4. At interval 3, cutoff=2 fails (only 1 validator in latestNew) and safeTarget resets back to genesis. 5. With safeTarget=0, getAttestationTarget always returns a slot ≤ latest_justified → attestation is skipped → finalization deadlocks. Fix: safeTarget is monotonically non-decreasing. Once 2/3 of validators confirmed a block, that signal is preserved even when latestNew is subsequently cleared by block inclusion. Fixes simtest finalization with single aggregator (post #642).
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Summary
Fixes #641
When running
zig build simtest, all three nodes were initialized with.is_aggregator = beamcmd.@"is-aggregator", causing all of them to act as aggregators when--is-aggregator trueis passed. Per spec, only one aggregator should exist per subnet.Fix
Hardcode
is_aggregator = falsefor nodes 2 and 3. Only node 1 (the primary node) inherits the--is-aggregatorCLI flag.Changes
pkgs/cli/src/main.zig:beam_node_2andbeam_node_3now always initialize withis_aggregator = false