fix: normalize zero-tuple fee payer placeholder for Rust/alloy interop - #104
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brendanjryan wants to merge 2 commits into
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fix: normalize zero-tuple fee payer placeholder for Rust/alloy interop#104brendanjryan wants to merge 2 commits into
brendanjryan wants to merge 2 commits into
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Rust/alloy encodes the fee payer placeholder as Some(Signature::default()),
which RLP-serializes to [0x80, 0x80, 0x80]. ox's deserialize only recognizes
its own 0x00 sentinel and parses the zero-tuple as a real signature object
{ r: 0n, s: 0n }, causing getSignPayload to produce a different hash than
what the sender signed over. This breaks sender recovery and fee payer
co-signing for cross-client transactions.
Adds a shared cosignFeePayer helper that:
1. Deserializes via ox and normalizes zero-tuple → null
2. Recovers sender from the user's signature (all 4 sig types)
3. Computes fee payer sign payload with 0x78 magic byte
4. Re-serializes with the real fee payer signature
Replaces the previous viem signTransaction approach in Charge and Chain,
which re-serialized the transaction and could produce mismatched payloads.
commit: |
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Problem
When a Rust/alloy client sends a fee-payer-sponsored transaction, it encodes the placeholder as
Some(Signature::default())— an RLP list of zeros[0x80, 0x80, 0x80](c3 80 80 80). This is the spec-compliant encoding.However, ox's
TxEnvelopeTempo.deserializeonly recognises its own0x00sentinel and parses the zero-tuple as a real signature object{ r: 0n, s: 0n, yParity: 0 }. This causesgetSignPayloadto produce a 4-byte RLP list instead of the 1-byte0x00placeholder, breaking:insufficient fundsFix
Adds a shared
cosignFeePayerhelper (src/tempo/internal/cosignFeePayer.ts) that:r === 0n && s === 0n) →null0x78magic byteReplaces the previous
viem.signTransactionapproach inCharge.tsandChain.ts.Upstream
The root cause is in ox's
TxEnvelopeTempo.deserialize— it should recognise the zero-valued signature tuple as a placeholder. Will file upstream fix at wevm/ox.Spec Reference
Some(Signature::default())per Transaction Flow section