From cad0d90afb6a5c1959f6dcb3a26c41f4ccae53e7 Mon Sep 17 00:00:00 2001
From: Vladimir Fomene <vladimirfomene@gmail.com>
Date: Mon, 23 Oct 2023 20:47:11 +0300
Subject: [PATCH 1/2] feat: get keychain that derived a script

---
 crates/bdk/src/wallet/mod.rs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/crates/bdk/src/wallet/mod.rs b/crates/bdk/src/wallet/mod.rs
index 659da90a2..1c95d826f 100644
--- a/crates/bdk/src/wallet/mod.rs
+++ b/crates/bdk/src/wallet/mod.rs
@@ -1986,6 +1986,14 @@ impl<D> Wallet<D> {
     pub fn local_chain(&self) -> &LocalChain {
         &self.chain
     }
+
+    /// Get the [`KeychainKind`] and derivation index for a given [`Script`].
+    ///
+    /// This will return `None` if the script is not in the wallet.
+    // TODO: Generalize this implementation once we make the wallet generic over K
+    pub fn which_keychain_derived(&self, spk: &Script) -> Option<&(KeychainKind, u32)> {
+        self.indexed_graph.index.index_of_spk(spk)
+    }
 }
 
 impl<D> AsRef<bdk_chain::tx_graph::TxGraph<ConfirmationTimeAnchor>> for Wallet<D> {

From e2ec6ff56fe9461f4ac93a2d5c0e7beabec98c85 Mon Sep 17 00:00:00 2001
From: Vladimir Fomene <vladimirfomene@gmail.com>
Date: Thu, 9 Nov 2023 10:19:59 +0300
Subject: [PATCH 2/2] test: test getting keychain for a script

---
 crates/bdk/tests/wallet.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/crates/bdk/tests/wallet.rs b/crates/bdk/tests/wallet.rs
index aad8c2db2..8990b21ea 100644
--- a/crates/bdk/tests/wallet.rs
+++ b/crates/bdk/tests/wallet.rs
@@ -60,6 +60,21 @@ fn receive_output_in_latest_block(wallet: &mut Wallet, value: u64) -> OutPoint {
 // OP_PUSH.
 const P2WPKH_FAKE_WITNESS_SIZE: usize = 106;
 
+#[test]
+fn test_which_keychain_derived_script() {
+    let (mut segwit_wallet, _) = get_funded_wallet(get_test_wpkh());
+    let addr = segwit_wallet.get_address(New);
+    let script = addr.script_pubkey();
+    let keychain = segwit_wallet.which_keychain_derived(&script).unwrap();
+    assert_eq!(keychain.0, KeychainKind::External);
+
+    let (mut taproot_wallet, _) = get_funded_wallet(get_test_tr_single_sig());
+    let addr = taproot_wallet.get_address(New);
+    let script = addr.script_pubkey();
+    let keychain = segwit_wallet.which_keychain_derived(&script);
+    assert!(keychain.is_none());
+}
+
 #[test]
 fn test_descriptor_checksum() {
     let (wallet, _) = get_funded_wallet(get_test_wpkh());