Merge bitcoin/bitcoin#19651: wallet: importdescriptors update existing

3efaf83c75 wallet: deactivate descriptor (S3RK)
6737d9655b test: wallet importdescriptors update existing (S3RK)
586f1d53d6 wallet: maintain SPK consistency on internal flag change (S3RK)
f1b7db1474 wallet: don't mute exceptions in importdescriptors (S3RK)
bf68ebc1cd wallet: allow to import same descriptor twice (S3RK)

Pull request description:

  Rationale: allow updating existing descriptors with `importdescriptors` command.

  Currently if you run same `importdescriptors` command twice with a descriptor containing private key you will get very confusing error — `Missing required fields`. What happens is that Wallet tries to write imported private key to the disk, but it exists already so we get `DB_KEYEXIST (-30995)` from BerkelyDB. Please note, that we set `DB_NOOVERWRITE` (I guess not to lose some keys accidentally). The exception is caught in `catch (...)` in rpcdump.cpp with a generic error.

  With this PR if a descriptor is already present than we will update its activeness, internalness, label, range and next_index.
  For the range only expansion is allowed (range start can only decrease, range end increase).

ACKs for top commit:
  achow101:
    re-ACK 3efaf83c75
  meshcollider:
    Code review ACK 3efaf83c75
  jonatack:
    Light ACK 3efaf83c75 per `git range-diff a000cb0 5d96704 3efaf83` and as a sanity check, re-debug-built on debian with gcc 10.2.1 and clang 11, ran wallet_importdescriptors.py

Tree-SHA512: 122c4b621d64ec8a3b625f3aed9f01a2b5cbaf2029ad0325b5ff38d67fff5cd35324335fabe2dd5169548b01b267c81be6ae0f5c834342f3d5f6eeed515c4843

src/wallet/scriptpubkeyman.cpp

@@ -1851,6 +1851,12 @@ bool DescriptorScriptPubKeyMan::AddDescriptorKeyWithDB(WalletBatch& batch, const
     AssertLockHeld(cs_desc_man);
     assert(!m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS));
 
+    // Check if provided key already exists
+    if (m_map_keys.find(pubkey.GetID()) != m_map_keys.end() ||
+        m_map_crypted_keys.find(pubkey.GetID()) != m_map_crypted_keys.end()) {
+        return true;
+    }
+
     if (m_storage.HasEncryptionKeys()) {
         if (m_storage.IsLocked()) {
             return false;
@@ -2304,3 +2310,37 @@ void DescriptorScriptPubKeyMan::UpgradeDescriptorCache()
         throw std::runtime_error(std::string(__func__) + ": writing cache items failed");
     }
 }
+
+void DescriptorScriptPubKeyMan::UpdateWalletDescriptor(WalletDescriptor& descriptor)
+{
+    LOCK(cs_desc_man);
+    std::string error;
+    if (!CanUpdateToWalletDescriptor(descriptor, error)) {
+        throw std::runtime_error(std::string(__func__) + ": " + error);
+    }
+
+    m_map_pubkeys.clear();
+    m_map_script_pub_keys.clear();
+    m_max_cached_index = -1;
+    m_wallet_descriptor = descriptor;
+}
+
+bool DescriptorScriptPubKeyMan::CanUpdateToWalletDescriptor(const WalletDescriptor& descriptor, std::string& error)
+{
+    LOCK(cs_desc_man);
+    if (!HasWalletDescriptor(descriptor)) {
+        error = "can only update matching descriptor";
+        return false;
+    }
+
+    if (descriptor.range_start > m_wallet_descriptor.range_start ||
+        descriptor.range_end < m_wallet_descriptor.range_end) {
+        // Use inclusive range for error
+        error = strprintf("new range must include current range = [%d,%d]",
+                          m_wallet_descriptor.range_start,
+                          m_wallet_descriptor.range_end - 1);
+        return false;
+    }
+
+    return true;
+}