[Dijkstra] MASTER ISSUE: Formalize CIP-0118 Nested Transactions

[williamdemeo]

Description

This is a "master" issue to track smaller (sub)issues related to Dijkstra. The scope of this issue is the "ledger rules mostly formalized" promise/end-of-year goal for work on the formal specification of the Dijkstra era. The only ledger rule in scope is UTXO (and UTXOS) as that seems to bear most of the impact of Dijkstra requirements.

Goal

Bring the Dijkstra era spec in line with CIP-0118 nested transactions + CIP-0112 guards (formerly "observers"), including:

• correct transaction-body shapes at both levels,
• correct guard/required-top-guard semantics,
• batch-wide phase-2 execution (mempool safety),
• batch-aware UTXOS transition (commit only on success).

References

• CIP-0118 Nested Transactions (guards + requiredTopLevelGuards + batch-wide phase-2) ¹
• CIP-0112 Observe (rename to Guard everywhere in spec; observers → guards)

Milestones / Subtasks

• Make guards credential-shaped at both levels (CIP-0112 alignment)
  [Dijkstra] replace TxBody field txRequiredGuards : ℙ KeyHash with txGuards : ℙ Credential #1000
• Redesign requiredTopLevelGuards container (CIP-0118 alignment)
  [Dijkstra] change type of txRequiredTopLevelGuards from Map to List #1001
• Phase-1 check: requiredTopLevelGuards ⊆ top-level guards
  [Dijkstra] phase-1 check: requiredTopLevelGuards in top-level guards #1002
• Fix ScriptPurpose/redeemer pointers for guards (index-based vs set-based decision)
  [Dijkstra] change types of ScriptPurpose.Guard and indexOfGuard to use lists of Credentials #1003
• Define TxInfoSubTxs plumbing: only top-level guard scripts see subTx infos
  [Dijkstra] implement TxInfo rules for guards #1004
• Resolve "reference inputs vs 'all inputs exist initially'" ambiguity
  [Dijkstra] CIP-0118 ambiguity: visibility of reference inputs/scripts inside a batch of subTxs #1005
• Define batch script collection + single evalP2Scripts at end
  [Dijkstra] batch-aware collectP2ScriptsWithContext + single evalP2Scripts at end #1006
• Update UTXOS for batch semantics (POV/fees/collateral/failure branch)
  [Dijkstra] UTXOS: implement batch-level validity (POV, fee rules, collateral-on-failure) #1007
• Adapt and add preconditions present in Conway to the UTXOW rule
  [Dijkstra] UTXOW: Implement languages and allowedLanguages #1024
• LEDGER: Implement globalData and globalScripts
  [Dijkstra] LEDGER: Implement globalData and globalScripts #1025

Definition of done

• Dijkstra modules type-check; guard semantics are consistent across Transaction + Script.Validation + UTXO/UTXOS.
• Batch commit semantics are explicit: tentative update computed, committed only after batch-wide phase-2 success.

Footnotes

1. See CIP 0118; once finalized and merged, CIP 0118 will appear in the main branch of the CIP repository; until then, it resides at https://github.com/polinavino/CIPs/tree/polina/CIP0118/CIP-0118. ↩