wallet, rpc: Implements set key label functionality #36126

 567 |  },
 568 |      };
 569 |  }
 570 |  
 571 | +// Parse an 8-hex-character (4-byte) master key fingerprint from an RPC string.
 572 | +static KeyFingerprint DecodeKeyFingerprint(const std::string& hex)

---

 585 | +RPCMethod setkeylabel()
 586 | +{
 587 | +    return RPCMethod{
 588 | +        "setkeylabel",
 589 | +        "Sets the label associated with a master key fingerprint.\n"
 590 | +                "Every address corresponding to a key derived from that master key inherits the label.\n"

---

2562 | +    const auto it = m_key_labels.find(fingerprint);
2563 | +    if (it == m_key_labels.end()) return std::nullopt;
2564 | +    return it->second;
2565 | +}
2566 | +
2567 | +std::optional<std::string> CWallet::GetKeyLabelForDest(const CTxDestination& dest) const

---

 485 | @@ -486,6 +486,22 @@ class WalletImpl : public Wallet
 486 |          auto spk_man = m_wallet->GetScriptPubKeyMan(OutputType::BECH32M, /*internal=*/false);
 487 |          return spk_man != nullptr;
 488 |      }
 489 | +    bool setKeyLabel(KeyFingerprint fingerprint, std::string label) override {

---

 555 |          labels.push_back(address_book_entry->GetLabel());
 556 |      }
 557 | +    // Per-key labels (keyed by master fingerprint) augment the per-address label
 558 | +    // above. A single address can therefore carry both its own address-book label
 559 | +    // and the label inherited from the corresponding master key.
 560 | +    const std::optional<std::string> key_label{pwallet->GetKeyLabelForDest(dest)};

---

  44 | +        change = wallet.getrawchangeaddress()
  45 | +        assert_equal(wallet.getaddressinfo(change)["labels"], ["my hardware wallet"])
  46 | +
  47 | +        # Augments, does not replace, per-address labels.
  48 | +        wallet.setlabel(addr, "receiving")
  49 | +        assert_equal(wallet.getaddressinfo(addr)["labels"], ["receiving", "my hardware wallet"])

---

2567 | +std::optional<std::string> CWallet::GetKeyLabelForDest(const CTxDestination& dest) const
2568 | +{
2569 | +    const CScript script_pub_key = GetScriptForDestination(dest);
2570 | +    const std::set<ScriptPubKeyMan*>& spk_mans = GetScriptPubKeyMans(script_pub_key);
2571 | +    if (spk_mans.empty()) return std::nullopt;
2572 | +    ScriptPubKeyMan* spk_man = *spk_mans.begin();

---

   0 | @@ -0,0 +1,9 @@
   1 | +RPC
   2 | +---
   3 | +- A new RPC, `setkeylabel` allows to set a label per master key fingerprint. This is usefull for example to identify participants of a multi signature setup, tag hardware wallets, etc. If an empty label is provided, the previous label is removed.
   4 | +
   5 | +- A new RPC, `getkeylabe` allows to get the the label associated to a master key by its fingerprint.

---

 563 | @@ -554,6 +564,148 @@ RPCMethod getaddressinfo()
 564 |      }
 565 |      ret.pushKV("labels", std::move(labels));
 566 |  
 567 | +    // Per-key labels keyed by master fingerprint for every key corresponding to this address.

---

---

 509 | +     *  across all descriptor types, which makes it a natural unit for labelling
 510 | +     * e.g. a hardware wallet or a multisig participant.
 511 | +     * These labels augment, do not replace, the per-address labels in m_address_book
 512 | +     * and never affect the change/receive heuristic in CAddressBookData::IsChange().
 513 | +     */
 514 | +    std::map<KeyFingerprint, std::string> m_key_labels GUARDED_BY(cs_wallet);

---

 503 | @@ -504,6 +504,15 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
 504 |      std::map<CTxDestination, CAddressBookData> m_address_book GUARDED_BY(cs_wallet);
 505 |      const CAddressBookData* FindAddressBookEntry(const CTxDestination&, bool allow_change = false) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 506 |  
 507 | +    /** Per-key labels keyed by the key's master fingerprint.
 508 | +     * A single fingerprint covers every key/address derived from the same root

---

 603 | +
 604 | +    if (label.empty()) {
 605 | +        if (!pwallet->DelKeyLabel(fingerprint)) {
 606 | +            throw JSONRPCError(RPC_WALLET_ERROR, "Error: failed to clear per-key label");
 607 | +        }
 608 | +    } else if (!pwallet->SetKeyLabel(fingerprint, label)) {

---