feat(wasm-utxo): expose transparent inputs of Zcash v6 finalized tx

packages/wasm-utxo/js/fixedScriptWallet/ZcashV6Transaction.ts

@@ -1,4 +1,5 @@
 import { ZcashV6Transaction as WasmZcashV6Transaction } from "../wasm/wasm_utxo.js";
+import type { TxInputData } from "../wasm/wasm_utxo.js";
 
 /**
  * A parsed Zcash v6 (Ironwood / NU6.3) transaction — for inspection and txid.
@@ -91,6 +92,15 @@ export class ZcashV6Transaction {
     );
   }
 
+  /**
+   * The transparent inputs of this transaction, in input order — e.g. each input's
+   * `previousOutput` (display-order txid + vout) for looking up the spent UTXOs of a broadcast
+   * shielding transaction. Empty for a fully shielded transaction.
+   */
+  getInputs(): TxInputData[] {
+    return this._wasm.getInputs();
+  }
+
   /** @internal */
   get wasm(): WasmZcashV6Transaction {
     return this._wasm;

packages/wasm-utxo/src/wasm/zcash.rs

@@ -5,6 +5,7 @@
 //! generic fixed-script-wallet bindings.
 
 use crate::error::WasmUtxoError;
+use crate::wasm::try_into_js_value::TryIntoJsValue;
 use wasm_bindgen::prelude::*;
 
 /// Return the Zcash consensus branch ID active at `height` on `network`.
@@ -436,4 +437,12 @@ impl ZcashV6Transaction {
         .map(|h| h.to_vec())
         .map_err(|e| WasmUtxoError::new(&e.to_string()))
     }
+
+    /// The transparent inputs of this transaction, in input order — each input's
+    /// `previousOutput` (display-order txid + vout), sequence, scriptSig, and witness, carried
+    /// verbatim from the wire. Empty for a fully shielded transaction.
+    #[wasm_bindgen(js_name = getInputs, unchecked_return_type = "TxInputData[]")]
+    pub fn get_inputs(&self) -> Result<JsValue, WasmUtxoError> {
+        super::transaction::tx_inputs_from(&self.inner.transparent).try_to_js_value()
+    }
 }

packages/wasm-utxo/test/fixedScript/zcashV6Transaction.ts

@@ -43,6 +43,34 @@ describe("ZcashV6Transaction", function () {
     assert.strictEqual(typeof tx.ironwoodValueBalance, "bigint");
   });
 
+  it("exposes the transparent inputs' prevouts of the reference shield tx", function () {
+    const tx = ZcashV6Transaction.fromBytes(Buffer.from(readFixture("v6_shield_rawtx.hex"), "hex"));
+    assert.deepStrictEqual(
+      tx.getInputs().map((input) => input.previousOutput),
+      [
+        { txid: "bb9a0ed8e980f02273fae80adfb462594ace1c620780c39e5e86b3900d1eebbe", vout: 0 },
+        { txid: "ac0e368c750f878ea1c4b07986e21d28472716367fd9aa8027fdf623801a5843", vout: 0 },
+      ],
+    );
+  });
+
+  it("exposes the transparent input's prevout of the multisig shield tx", function () {
+    const tx = ZcashV6Transaction.fromBytes(
+      Buffer.from(readFixture("v6_shield_multisig_rawtx.hex"), "hex"),
+    );
+    assert.deepStrictEqual(
+      tx.getInputs().map((input) => input.previousOutput),
+      [{ txid: "1ebd1da314f021d7c7b2ced6c0340067ebf3ce422bf8c53daa626d72cbd9fe73", vout: 1 }],
+    );
+  });
+
+  it("has no transparent inputs for the fully shielded self-send", function () {
+    const tx = ZcashV6Transaction.fromBytes(
+      Buffer.from(readFixture("v6_selfsend_rawtx.hex"), "hex"),
+    );
+    assert.deepStrictEqual(tx.getInputs(), []);
+  });
+
   it("throws on non-v6 bytes", function () {
     assert.throws(() => ZcashV6Transaction.fromBytes(Buffer.from("00010203", "hex")));
   });