Merge bitcoin/bitcoin#31452: wallet: Migrate non-HD keys to combo() descriptor

62b2d23 wallet: Migrate non-HD keys to combo() descriptor (Ava Chow)

Pull request description:

  Non-HD keys do not have an HD seed ID associated with them, so if this value is the null value (all 0s), then we should not perform any seed ID comparison that would result in excluding the keys from combo() migration.

  This changes the migration of non-HD wallets (or blank wallets with imported private keys) to make a single combo() descriptors for the non-HD/imported keys, rather than pk(), pkh(), sh(wpkh()), and wpkh() descriptors for the keys.

  Implements bitcoin/bitcoin#31374 (comment)

ACKs for top commit:
  laanwj:
    Concept and code review ACK 62b2d23
  brunoerg:
    code review ACK 62b2d23
  furszy:
    Nice catch. ACK 62b2d23
  theStack:
    ACK 62b2d23
  rkrux:
    tACK 62b2d23

Tree-SHA512: 86a80b7dcc1598ab18068a2572ff4b4920b233178b760f7b76c5b21a9e6608005ac872f90e082a8f99b51daab0b049e73e4bee5b8e0b537d56ed0d34122a1f49

Author: fanquake

src/wallet/scriptpubkeyman.cpp

@@ -1799,7 +1799,7 @@ std::optional<MigrationData> LegacyDataSPKM::MigrateToDescriptor()
                 keyid_it++;
                 continue;
             }
-            if (m_hd_chain.seed_id == meta.hd_seed_id || m_inactive_hd_chains.count(meta.hd_seed_id) > 0) {
+            if (!meta.hd_seed_id.IsNull() && (m_hd_chain.seed_id == meta.hd_seed_id || m_inactive_hd_chains.count(meta.hd_seed_id) > 0)) {
                 keyid_it = keyids.erase(keyid_it);
                 continue;
             }

test/functional/wallet_migration.py

@@ -1032,15 +1032,11 @@ def test_manual_keys_import(self):
         # There should be descriptors containing the imported key for: pk(), pkh(), sh(wpkh()), wpkh()
         key_origin = hash160(pubkey)[:4].hex()
         pubkey_hex = pubkey.hex()
-        pk_desc = descsum_create(f'pk([{key_origin}]{pubkey_hex})')
-        pkh_desc = descsum_create(f'pkh([{key_origin}]{pubkey_hex})')
-        sh_wpkh_desc = descsum_create(f'sh(wpkh([{key_origin}]{pubkey_hex}))')
-        wpkh_desc = descsum_create(f'wpkh([{key_origin}]{pubkey_hex})')
-        expected_descs = [pk_desc, pkh_desc, sh_wpkh_desc, wpkh_desc]
+        combo_desc = descsum_create(f"combo([{key_origin}]{pubkey_hex})")
 
         # Verify all expected descriptors were migrated
         migrated_desc = [item['desc'] for item in wallet.listdescriptors()['descriptors'] if pubkey.hex() in item['desc']]
-        assert_equal(expected_descs, migrated_desc)
+        assert_equal([combo_desc], migrated_desc)
         wallet.unloadwallet()
 
         ######################################################