Merge #19136: wallet: add parent_desc to getaddressinfo

de6b389d5db7b8426313c5be6fbd290f992c5aa8 tests: Test getaddressinfo parent_desc (Andrew Chow)
e4ac869a0a0083e2e3af3b56301bd5c8e0cf650b rpc: Add parent descriptor to getaddressinfo output (Andrew Chow)
bbe4a36152fb8d9c8c3682ca2380f1c88cca61cb wallet: Add GetDescriptorString to DescriptorScriptPubKeyMan (Andrew Chow)
9be1437c49f986e8ed964d5f863b4bbcec340751 descriptors: Add ToNormalizedString and tests (Andrew Chow)

Pull request description:

  Adds `parent_desc` field to the `getaddressinfo` RPC to export a public descriptor. Using the given address, `getaddressinfo` will look up which `DescriptorScriptPubKeyMan` can be used to produce that address. It will then return the descriptor for that `DescriptorScriptPubKeyMan` in the `parent_desc` field. The descriptor will be in a normalized form where the xpub at the last hardened step is derived so that the descriptor can be imported to other wallets. Tests are added to check that the correct descriptor is being returned for the wallet's addresses and that these descriptors can be imported and used in other wallets.

  As part of this PR, a `ToNormalizedString` function is added to the descriptor classes. This really only has an effect on `BIP32PubkeyProvider`s that have hardened derivation steps. Tests are added to check that normalized descriptors are returned.

ACKs for top commit:
  Sjors:
    utACK de6b389d5db7b8426313c5be6fbd290f992c5aa8
  S3RK:
    Tested ACK de6b389
  jonatack:
    Tested ACK de6b389d5db7b8426313c5be6fbd290f992c5aa8 modulo a few minor comments
  fjahr:
    Code review ACK de6b389d5db7b8426313c5be6fbd290f992c5aa8
  meshcollider:
    Tested ACK de6b389d5db7b8426313c5be6fbd290f992c5aa8

Tree-SHA512: a633e4a39f2abbd95afd7488484cfa66fdd2651dac59fe59f2b80a0940a2a4a13acf889c534a6948903d701484a2ba1218e3081feafe0b9a720dccfa9e43ca2b

3 files changed, 24 insertions, 0 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 46de273d63..a8f45fa896 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3787,6 +3787,7 @@ RPCHelpMan getaddressinfo()
                         {RPCResult::Type::BOOL, "iswatchonly", "If the address is watchonly."},
                         {RPCResult::Type::BOOL, "solvable", "If we know how to spend coins sent to this address, ignoring the possible lack of private keys."},
                         {RPCResult::Type::STR, "desc", /* optional */ true, "A descriptor for spending coins sent to this address (only when solvable)."},
+                        {RPCResult::Type::STR, "parent_desc", /* optional */ true, "The descriptor used to derive this address if this is a descriptor wallet"},
                         {RPCResult::Type::BOOL, "isscript", "If the key is a script."},
                         {RPCResult::Type::BOOL, "ischange", "If the address was used for change output."},
                         {RPCResult::Type::BOOL, "iswitness", "If the address is a witness address."},
@@ -3862,6 +3863,14 @@ RPCHelpMan getaddressinfo()
        ret.pushKV("desc", InferDescriptor(scriptPubKey, *provider)->ToString());
     }
 
+    DescriptorScriptPubKeyMan* desc_spk_man = dynamic_cast<DescriptorScriptPubKeyMan*>(pwallet->GetScriptPubKeyMan(scriptPubKey));
+    if (desc_spk_man) {
+        std::string desc_str;
+        if (desc_spk_man->GetDescriptorString(desc_str, false)) {
+            ret.pushKV("parent_desc", desc_str);
+        }
+    }
+
     ret.pushKV("iswatchonly", bool(mine & ISMINE_WATCH_ONLY));
 
     UniValue detail = DescribeWalletAddress(pwallet, dest);
diff --git a/src/wallet/scriptpubkeyman.cpp b/src/wallet/scriptpubkeyman.cpp
index 55110f30d9..4630603f8e 100644
--- a/src/wallet/scriptpubkeyman.cpp
+++ b/src/wallet/scriptpubkeyman.cpp
@@ -2264,3 +2264,16 @@ const std::vector<CScript> DescriptorScriptPubKeyMan::GetScriptPubKeys() const
     }
     return script_pub_keys;
 }
+
+bool DescriptorScriptPubKeyMan::GetDescriptorString(std::string& out, bool priv) const
+{
+    LOCK(cs_desc_man);
+    if (m_storage.IsLocked()) {
+        return false;
+    }
+
+    FlatSigningProvider provider;
+    provider.keys = GetKeys();
+
+    return m_wallet_descriptor.descriptor->ToNormalizedString(provider, out, priv);
+}
diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
index 8f6b69bc78..51283e791d 100644
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -616,6 +616,8 @@ public:
 
     const WalletDescriptor GetWalletDescriptor() const EXCLUSIVE_LOCKS_REQUIRED(cs_desc_man);
     const std::vector<CScript> GetScriptPubKeys() const;
+
+    bool GetDescriptorString(std::string& out, bool priv) const;
 };
 
 #endif // BITCOIN_WALLET_SCRIPTPUBKEYMAN_H