feat(transaction-pay-controller): Add shared EIP-7702 quote gas estimation

[pedronfigueiredo]

Explanation

Add a shared quote gas estimator that switches between per-transaction and EIP-7702 batch estimation, reuses Across’s ordered submission transaction list at quote time, and falls back to the single-transaction path when batch estimation is unsupported or fails.

References

https://github.com/MetaMask/MetaMask-planning/issues/7098

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Medium Risk
Refactors gas estimation and submission logic for both Relay and Across quotes, including new EIP-7702 batch-handling paths; incorrect limits could impact fee calculation or batch execution behavior.

Overview
Adds a shared estimateQuoteGasLimits utility that centralizes quote-time gas estimation across strategies, using estimateGasBatch for multi-transaction quotes (including EIP-7702 combined single-limit batches) and falling back to per-transaction estimation when appropriate.

Updates Across and Relay quoting to use this shared estimator, introduces a consistent is7702 flag in quote metadata, and reshapes gas limit data (Across now returns an ordered list instead of { approval, swap }). Submission paths are updated to honor is7702 by omitting per-tx gas when using gasLimit7702, with stricter erroring when required limits/fields are missing.

Adds getAcrossOrderedTransactions to reuse the same approval+swap ordering for estimation and submit, and expands test coverage for batch estimation, missing fields, and 7702-specific behaviors.

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[cryptotavares]

Reviewing as @cryptotavares's AI assistant

Overall this is a clean refactor — the shared estimator logic is well-structured, fallbacks are correctly wired, and the batch/individual split in estimateQuoteGasLimits is sound. A few things worth addressing before merge:

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Bug: Missing chainId fallback in getAcrossOrderedTransactions

File: src/strategy/across/transactions.ts + src/strategy/across/across-quotes.ts

getAcrossOrderedTransactions spreads approval transactions directly from the Across API response:

const approvalTransactions = (quote.approvalTxns ?? []).map((approval) => ({
  ...approval,
  kind: 'approval' as const,
  type: TransactionType.tokenMethodApprove,
}));

If the Across API omits chainId on an approval transaction (which the old code explicitly guarded against with quote.approvalTxns?.[index]?.chainId ?? swapTx.chainId), then transaction.chainId will be undefined at runtime despite the type saying number. The gas estimation call in calculateSourceNetworkCost then does:

chainId: toHex(transaction.chainId),  // toHex(undefined) → likely '0x0'

This would target the wrong chain for gas estimation. The cost calculation later in calculateSourceNetworkCost still has the correct fallback (quote.approvalTxns?.[index]?.chainId ?? swapTx.chainId), but that doesn't help if estimation ran against chain 0x0.

The old fallback was intentional. Either:

• Add the fallback inside getAcrossOrderedTransactions (pass swapTx.chainId and use approval.chainId ?? swapChainId), or
• Add it at the call site in calculateSourceNetworkCost when building the transactions array

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Logic concern: useBuffer skips buffer when batch API echoes provided gas

File: src/utils/quote-gas.ts (~L105)

const useBuffer =
  gasLimits.length === 1 || paramGasLimits[index] !== gasLimit;

When estimateGasBatch returns per-transaction results (gasLimits.length === transactions.length), useBuffer is false if the batch API returns exactly the value that was passed in via transaction.gas. The intent seems to be "if the chain just echoed back our provided value, don't add a buffer on top." That's a reasonable interpretation, but paramGasLimits[index] is the parsed input gas; if the batch API happens to estimate the same number that was provided (not just echo it), buffer would also be skipped. Is that intentional? Worth adding a comment to clarify.

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Minor: combinePostQuoteGas EIP-7702 detection heuristic

File: src/strategy/relay/relay-quotes.ts (~L480)

// TODO: Test EIP-7702 support on the chain as well before assuming single gas limit.
const isEIP7702 = gasLimits.length === 1;

A single-step Relay quote (one transaction, individual estimation) also produces gasLimits.length === 1, so this misidentifies it as a 7702 batch and combines the original tx gas into a single limit. I see this has a TODO already — just flagging it as something that becomes more load-bearing now that the shared estimator is in use for both strategies.

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One merge blocker (the chainId fallback regression), one question (buffer logic intent), one pre-existing TODO that's worth tracking. Happy to look at a follow-up once the chainId question is resolved.

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[matthewwalsh0]

Minor, I meant let it throw naturally rather than explicitly checking each field.

[matthewwalsh0]

Minor, is this possible since earlier gas estimation would of thrown?

[pedronfigueiredo]

good point, removed

[matthewwalsh0]

Minor, is this duplication since we already have is7702 set?

Could we enforce in the type that is7702 guarantees one entry?