Merge bitcoin#32344: Wallet: Fix Non-Ranged Descriptors with Range [0,0] Trigger Unexpected Wallet Errors in AddWalletDescriptor

97d383a Test updating non-ranged descriptor with [0,0] range succeeds (Novo)
2ae1788 Skip range verification for non-ranged desc (Novo)

Pull request description:

  Closes bitcoin#31728

  This PR updates the `DescriptorScriptPubKeyMan` to skip range checks for non-ranged descriptors, which previously caused errors when updating a non-ranged descriptor with the range [0,0]

  #### Testing
  A unit test was added to test the new behaviour

ACKs for top commit:
  achow101:
    ACK 97d383a
  rkrux:
    ACK 97d383a

Tree-SHA512: 6dbd058376d9e57d26477d9d6d89646e80a32e3ffcc9f4e30eeda273575d12583ce520cc0032cc67c12ea0b3ad344fbd3945d9fc5e389b6a6bce1ea7ad5d6e59

Author: achow101

src/wallet/scriptpubkeyman.cpp

@@ -1598,6 +1598,11 @@ bool DescriptorScriptPubKeyMan::CanUpdateToWalletDescriptor(const WalletDescript
         return false;
     }
 
+    if (!descriptor.descriptor->IsRange()) {
+        // Skip range check for non-range descriptors
+        return true;
+    }
+
     if (descriptor.range_start > m_wallet_descriptor.range_start ||
         descriptor.range_end < m_wallet_descriptor.range_end) {
         // Use inclusive range for error

src/wallet/test/wallet_tests.cpp

@@ -70,6 +70,25 @@ static void AddKey(CWallet& wallet, const CKey& key)
     assert(spk_manager);
 }
 
+BOOST_FIXTURE_TEST_CASE(update_non_range_descriptor, TestingSetup)
+{
+    CWallet wallet(m_node.chain.get(), "", CreateMockableWalletDatabase());
+    {
+        LOCK(wallet.cs_wallet);
+        wallet.SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
+        auto key{GenerateRandomKey()};
+        auto desc_str{"combo(" + EncodeSecret(key) + ")"};
+        FlatSigningProvider provider;
+        std::string error;
+        auto descs{Parse(desc_str, provider, error, /* require_checksum=*/ false)};
+        auto& desc{descs.at(0)};
+        WalletDescriptor w_desc{std::move(desc), 0, 0, 0, 0};
+        BOOST_CHECK(wallet.AddWalletDescriptor(w_desc, provider, "", false));
+        // Wallet should update the non-range descriptor successfully
+        BOOST_CHECK(wallet.AddWalletDescriptor(w_desc, provider, "", false));
+    }
+}
+
 BOOST_FIXTURE_TEST_CASE(scan_for_wallet_transactions, TestChain100Setup)
 {
     // Cap last block file size, and mine new block in a new block file.