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merge-script fa267551c4 Merge bitcoin/bitcoin#34353 : refactor: Use std::bind_front over std::bind

faa18dceba refactor: Use std::bind_front over std::bind (MarcoFalke)

Pull request description:

  `std::bind` has many issues:

  * It is verbosely listing all placeholders, but in a meaningless way, because it doesn't name the args or their types.
  * It silently ignores args passed to it, when one arg is overridden. For example [1] compiles fine on current master.
  * Accidentally duplicated placeholders compile fine as well.
  * Usually the placeholders aren't even needed.
  * This makes it hard to review, understand, and maintain.

  Fix all issues by using `std::bind_front` from C++20, which allows to drop the brittle `_1, _2, ...` placeholders. The replacement should be correct, if the trailing placeholders are ordered.

  Introducing the same silent bug on top of this pull request [2] will now lead to a compile failure.

  ----

  [1]

  ```diff
  diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
  index 694fb535b5..7661dd361e 100644
  --- a/src/qt/walletmodel.cpp
  +++ b/src/qt/walletmodel.cpp
  @@ -412,3 +412,3 @@ void WalletModel::subscribeToCoreSignals()
       m_handler_status_changed = m_wallet->handleStatusChanged(std::bind(&NotifyKeyStoreStatusChanged, this));
  -    m_handler_address_book_changed = m_wallet->handleAddressBookChanged(std::bind(NotifyAddressBookChanged, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3, std::placeholders::_4, std::placeholders::_5));
  +    m_handler_address_book_changed = m_wallet->handleAddressBookChanged(std::bind(NotifyAddressBookChanged, this, CTxDestination{}, std::placeholders::_2, std::placeholders::_3, std::placeholders::_4, std::placeholders::_5));
       m_handler_transaction_changed = m_wallet->handleTransactionChanged(std::bind(NotifyTransactionChanged, this, std::placeholders::_1, std::placeholders::_2));
  ```

  [2]

  ```diff
  diff --git a/src/qt/walletmodel.cpp b/src/qt/walletmodel.cpp
  index 578713c0ab..84cced741c 100644
  --- a/src/qt/walletmodel.cpp
  +++ b/src/qt/walletmodel.cpp
  @@ -412,3 +412,3 @@ void WalletModel::subscribeToCoreSignals()
       m_handler_status_changed = m_wallet->handleStatusChanged(std::bind_front(&NotifyKeyStoreStatusChanged, this));
  -    m_handler_address_book_changed = m_wallet->handleAddressBookChanged(std::bind_front(NotifyAddressBookChanged, this));
  +    m_handler_address_book_changed = m_wallet->handleAddressBookChanged(std::bind_front(NotifyAddressBookChanged, this, CTxDestination{}));
       m_handler_transaction_changed = m_wallet->handleTransactionChanged(std::bind_front(NotifyTransactionChanged, this));

ACKs for top commit:
  janb84:
    cr ACK faa18dceba
  fjahr:
    Code review ACK faa18dceba
  hebasto:
    ACK faa18dceba, I have reviewed the code and it looks OK.

Tree-SHA512: 9dd13f49527e143a2beafbaae80b1358981f07a2ce20d25cffb1853089a32ff71639e6d718d1d193754522f9ac04e3e168ba017d5fc67a11a5918e79a92b3461

2026-01-21 14:59:31 +00:00