fix: use Wrap/Unwrap underlying amounts for Balancer V3 buffer swaps

[gustavobftorres]

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Description:

Join Vault_evt_Wrap/Unwrap with evt_index tie-break to avoid duplicate rows; COALESCE to Swap amounts when no buffer match.

Fix for #9472

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• README.md
• spellbook docs
• CONTRIBUTING.md

[tomfutago]

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[tomfutago]

hey @gustavobftorres - this might be false red flag, but can you address this finding plz:

High: Balancer V3 buffer-event matching assumes a fixed event order that does not hold on-chain

The new logic in dbt_subprojects/dex/macros/models/_project/balancer_compatible_trades.sql only matches:

• Wrap rows with w.evt_index < s.evt_index
• Unwrap rows with u.evt_index > s.evt_index

That means it assumes Balancer V3 always emits Wrap -> Swap -> Unwrap.

Live Ethereum data shows this assumption is false. Using the same join keys as the PR (evt_tx_hash, share amount, wrapped token), I found since 2025-01-01:

• 12,774 swaps with only a matching Wrap after the Swap
• 1,720 swaps with only a matching Unwrap before the Swap

Concrete counterexamples:

• 0x62763c7010d03949f8af934fedc9077edc150bce25db3df333412ac25636654c

  • Swap at evt_index = 59
  • Unwrap at evt_index = 60
  • Wrap at evt_index = 63

• 0x79707734bca5c8fb7e5ca49dd3b742941e9d18d65fc4455a6d02cb286eb6457a

  • Unwrap at evt_index = 124
  • Swap at evt_index = 125
  • Wrap at evt_index = 128

Because the PR falls back to swap.amountIn / swap.amountOut via coalesce(...), these transactions would still keep share-denominated values on one or both sides instead of underlying token amounts.

So the fix is incomplete: it resolves the happy-path ordering covered by the updated seeds, but it still leaves incorrect Balancer V3 trade amounts for real reverse-ordered buffer swaps.