[Kshot3000]

Summary

MockChain.execute() distributed a transaction's outputs to the parties by splicing the transaction's own outputs array:

const { inputs, outputs } = txObject;
for (const party of this.#parties) {
  for (let i = outputs.length - 1; i >= 0; i--) {
    if (party.ergoTree === outputs[i].ergoTree) {
      party.utxos.add(outputs[i]);
      outputs.splice(i, 1);
    }
  }
}

That is invisible when the transaction is passed as an ErgoUnsignedTransaction (a fresh EIP-12 object is built internally), but execute() also accepts a plain EIP12UnsignedTransaction — and then txObject is the caller's object. After execution, the caller's transaction had lost every output that matched a party — typically all of them — so inspecting the transaction afterwards, asserting on its outputs, or reusing the object operated on a truncated transaction.

Reproduced with a payment + change transaction passed via .toEIP12Object(): tx.outputs.length went from 3 before execute() to 1 after it (only the fee output, which matched no party in that setup, survived).

Fix

Distribute over a copy (const outputs = [...txObject.outputs]). Delivery semantics are unchanged: same parties, same order, each output still goes to at most one party.

Tests

• New spec in mockChain.spec.ts: executes an EIP-12 transaction and asserts the caller's outputs (length, contents, and element identity) and inputs are unchanged, while the payment and change balances are still delivered correctly. It fails on master with exactly the mutation above (expected length 3, got 1) and passes with the fix.
• Full monorepo suite: 1133/1133 tests pass (66 files; master baseline 1132 + the 1 new test).
• Biome check clean on the changed files.

Includes a patch changeset for @fleet-sdk/mock-chain.

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Built by Kyle Cox (@Kshot9000) — https://x.com/kshot9000
Tips (ERG): 9fcM5RWnAjmP4vx5bnW6yohB6H9bLq8sJbaPLHtwZLtQPB32Pvy

[changeset-bot]

🦋 Changeset detected

Latest commit: e77bd0c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@fleet-sdk/mock-chain	Patch

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