From f1b329f680b9bd446ec8240ecc3a331babcb0bec Mon Sep 17 00:00:00 2001
From: Wilmer Paulino <wilmer.paulino@gmail.com>
Date: Wed, 10 Mar 2021 18:11:16 -0800
Subject: [PATCH] waddrmgr: add TODO to determine proper address type of
 imported key

For key scopes which have an address schema where the external and
internal branches differ, we always assume that imported keys use the
external address type defined in the scope's address schema. This may
not always be the case however, and should be handled correctly.
Ideally, we generate two addresses per imported key (only if the
external and internal address types differ) and scan for both in the
chain.
---
 waddrmgr/scoped_manager.go | 65 ++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 37 deletions(-)

diff --git a/waddrmgr/scoped_manager.go b/waddrmgr/scoped_manager.go
index 0a6c6cb..b91ccef 100644
--- a/waddrmgr/scoped_manager.go
+++ b/waddrmgr/scoped_manager.go
@@ -177,6 +177,13 @@ var (
 		ExternalAddrType: NestedWitnessPubKey,
 		InternalAddrType: NestedWitnessPubKey,
 	}
+
+	// ImportedDerivationPath is the derivation path for an imported
+	// address. The Account, Branch, and Index members are not known, so
+	// they are left blank.
+	ImportedDerivationPath = DerivationPath{
+		InternalAccount: ImportedAddrAccount,
+	}
 )
 
 // ScopedKeyManager is a sub key manager under the main root key manager. The
@@ -665,15 +672,10 @@ func (s *ScopedKeyManager) importedAddressRowToManaged(row *dbImportedAddressRow
 		return nil, managerError(ErrCrypto, str, err)
 	}
 
-	// Since this is an imported address, we won't populate the full
-	// derivation path, as we don't have enough information to do so.
-	derivationPath := DerivationPath{
-		InternalAccount: row.account,
-	}
-
+	// TODO: Handle imported key being part of internal branch.
 	compressed := len(pubBytes) == btcec.PubKeyBytesLenCompressed
 	ma, err := newManagedAddressWithoutPrivKey(
-		s, derivationPath, pubKey, compressed,
+		s, ImportedDerivationPath, pubKey, compressed,
 		s.addrSchema.ExternalAddrType,
 	)
 	if err != nil {
@@ -1753,22 +1755,12 @@ func (s *ScopedKeyManager) ImportPrivateKey(ns walletdb.ReadWriteBucket,
 		return nil, err
 	}
 
-	// The full derivation path for an imported key is incomplete as we
-	// don't know exactly how it was derived.
-	importedDerivationPath := DerivationPath{
-		InternalAccount: ImportedAddrAccount,
-	}
-
 	// Create a new managed address based on the imported address.
 	if !s.rootManager.WatchOnly() {
-		return s.toPrivateManagedAddress(
-			wif, true, importedDerivationPath,
-		)
+		return s.toImportedPrivateManagedAddress(wif)
 	}
 	pubKey := (*btcec.PublicKey)(&wif.PrivKey.PublicKey)
-	return s.toPublicManagedAddress(
-		pubKey, wif.CompressPubKey, true, importedDerivationPath,
-	)
+	return s.toImportedPublicManagedAddress(pubKey, wif.CompressPubKey)
 }
 
 // ImportPublicKey imports a public key into the address manager.
@@ -1789,14 +1781,7 @@ func (s *ScopedKeyManager) ImportPublicKey(ns walletdb.ReadWriteBucket,
 		return nil, err
 	}
 
-	// The full derivation path for an imported key is incomplete as we
-	// don't know exactly how it was derived.
-	importedDerivationPath := DerivationPath{
-		InternalAccount: ImportedAddrAccount,
-	}
-	return s.toPublicManagedAddress(
-		pubKey, true, true, importedDerivationPath,
-	)
+	return s.toImportedPublicManagedAddress(pubKey, true)
 }
 
 // importPublicKey imports a public key into the address manager and updates the
@@ -1883,19 +1868,22 @@ func (s *ScopedKeyManager) importPublicKey(ns walletdb.ReadWriteBucket,
 	return nil
 }
 
-// toPrivateManagedAddress converts a private key to a managed address.
-func (s *ScopedKeyManager) toPrivateManagedAddress(wif *btcutil.WIF,
-	imported bool, derivationPath DerivationPath) (*managedAddress, error) {
+// toImportedPrivateManagedAddress converts an imported private key to an
+// imported managed address.
+func (s *ScopedKeyManager) toImportedPrivateManagedAddress(
+	wif *btcutil.WIF) (*managedAddress, error) {
 
 	// Create a new managed address based on the imported address.
+	//
+	// TODO: Handle imported key being part of internal branch.
 	managedAddr, err := newManagedAddress(
-		s, derivationPath, wif.PrivKey, wif.CompressPubKey,
+		s, ImportedDerivationPath, wif.PrivKey, wif.CompressPubKey,
 		s.addrSchema.ExternalAddrType,
 	)
 	if err != nil {
 		return nil, err
 	}
-	managedAddr.imported = imported
+	managedAddr.imported = true
 
 	// Add the new managed address to the cache of recent addresses and
 	// return it.
@@ -1903,19 +1891,22 @@ func (s *ScopedKeyManager) toPrivateManagedAddress(wif *btcutil.WIF,
 	return managedAddr, nil
 }
 
-// toPublicManagedAddress converts a public key to a managed address.
-func (s *ScopedKeyManager) toPublicManagedAddress(pubKey *btcec.PublicKey,
-	compressed, imported bool, derivationPath DerivationPath) (*managedAddress, error) {
+// toPublicManagedAddress converts an imported public key to an imported managed
+// address.
+func (s *ScopedKeyManager) toImportedPublicManagedAddress(
+	pubKey *btcec.PublicKey, compressed bool) (*managedAddress, error) {
 
 	// Create a new managed address based on the imported address.
+	//
+	// TODO: Handle imported key being part of internal branch.
 	managedAddr, err := newManagedAddressWithoutPrivKey(
-		s, derivationPath, pubKey, compressed,
+		s, ImportedDerivationPath, pubKey, compressed,
 		s.addrSchema.ExternalAddrType,
 	)
 	if err != nil {
 		return nil, err
 	}
-	managedAddr.imported = imported
+	managedAddr.imported = true
 
 	// Add the new managed address to the cache of recent addresses and
 	// return it.