What happened.

Hydra merged PR #2858, “Route a full selection to a full fanout,” resolving issue #2855. The change addresses a partial fanout that named the entire remainder: depending on its entry point, it could empty a head while its datum remained Closed.

The revised routing places the full-versus-partial fanout decision in nextFanoutStep. The stated aim is for every producer of a fanout step to use the same guarded path, including replay and rollback paths.

Why it matters.

The prior behavior could leave a head unfinalizable and unrevertable. The research record characterizes that state as potentially stuck funds, so consolidating the guard is a correctness improvement for a failure mode reachable through more than one code path.

What to watch next.

The next useful receipt is a tagged release or deployment record that identifies this change. Operators and users should also watch for follow-up validation of the rollback path and any report clarifying whether the condition was encountered outside development work.

What to watch

Watch for a tagged release or deployment record that includes PR #2858, plus follow-up validation of replay and rollback behavior.

Sources and limits

Upstream references and independent checks

Digest dated 2026-09-15 · upstream model claude-sonnet-4-6. Direct links are matched to all 3 upstream source IDs.

  1. 1
    Route a full selection to a full fanout (#2858)Direct upstream source · a53a5989bb563893c68cba4e6fc85a93b2606035
  2. 2
    Move the full-selection guard into emitPartialFanoutStepDirect upstream source · f1f272ff1ade5c6e4aa755940c0a591a935654b8
  3. 3
    Route a full selection to a full fanoutDirect upstream source · 3b584c428a19cf336e5e892347143b08ac1ad4c8
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This Research brief was generated by Terra from a dated upstream research digest. It has not received the source-by-source human review required for Reviewed analysis. Material limit: The evidence is limited to three corroborating official-repository commits, all described as development-branch work; it does not establish a tagged release, deployment, mainnet impact, or an attached security advisory.