Remove CPFP (child pays for parent)

This feature is going away from BCH very soon with the May 15th 2021
network upgrade.  As such, we remove it now.  It hardly was used anyway
on BCH so nobody will miss it if it's simply gone right away without a
transition period.

Miners running BCHN 23.0.0 don't have CPFP code anymore anyway when
generating blocks so.. it's a good idea to remove this ASAP as well.

electroncash/wallet.py

@@ -2221,27 +2221,6 @@ def address_is_old(self, address, age_limit=2):
                 break # ok, it's old. not need to keep looping
         return age > age_limit
 
-    def cpfp(self, tx, fee, sign_schnorr=None):
-        ''' sign_schnorr is a bool or None for auto '''
-        sign_schnorr = self.is_schnorr_enabled() if sign_schnorr is None else bool(sign_schnorr)
-        txid = tx.txid()
-        for i, o in enumerate(tx.outputs()):
-            otype, address, value = o
-            if otype == TYPE_ADDRESS and self.is_mine(address):
-                break
-        else:
-            return
-        coins = self.get_addr_utxo(address)
-        item = coins.get(txid+':%d'%i)
-        if not item:
-            return
-        self.add_input_info(item)
-        inputs = [item]
-        outputs = [(TYPE_ADDRESS, address, value - fee)]
-        locktime = self.get_local_height()
-        # note: no need to call tx.BIP_LI01_sort() here - single input/output
-        return Transaction.from_io(inputs, outputs, locktime=locktime, sign_schnorr=sign_schnorr)
-
     def add_input_info(self, txin):
         address = txin['address']
         if self.is_mine(address):

electroncash_gui/qt/history_list.py

@@ -263,10 +263,6 @@ def create_menu(self, position):
                 lambda: self.currentItem() and self.editItem(self.currentItem(), column))
         label = self.wallet.get_label(tx_hash) or None
         menu.addAction(_("&Details"), lambda: self.parent.show_transaction(tx, label))
-        if is_unconfirmed and tx:
-            child_tx = self.wallet.cpfp(tx, 0)
-            if child_tx:
-                menu.addAction(_("Child pays for parent"), lambda: self.parent.cpfp(tx, child_tx))
         if pr_key:
             menu.addAction(self.invoiceIcon, _("View invoice"), lambda: self.parent.show_invoice(pr_key))
         if tx_URL:

electroncash_gui/qt/main_window.py

@@ -4913,62 +4913,6 @@ def hardware_wallet_support(self):
         d.exec_()
         self.hardwarewalletdialog = None # allow python to GC
 
-    def cpfp(self, parent_tx, new_tx):
-        total_size = parent_tx.estimated_size() + new_tx.estimated_size()
-        d = WindowModalDialog(self.top_level_window(), _('Child Pays for Parent'))
-        vbox = QVBoxLayout(d)
-        msg = (
-            "A CPFP is a transaction that sends an unconfirmed output back to "
-            "yourself, with a high fee. The goal is to have miners confirm "
-            "the parent transaction in order to get the fee attached to the "
-            "child transaction.")
-        vbox.addWidget(WWLabel(_(msg)))
-        msg2 = ("The proposed fee is computed using your "
-            "fee/kB settings, applied to the total size of both child and "
-            "parent transactions. After you broadcast a CPFP transaction, "
-            "it is normal to see a new unconfirmed transaction in your history.")
-        vbox.addWidget(WWLabel(_(msg2)))
-        grid = QGridLayout()
-        grid.addWidget(QLabel(_('Total size') + ':'), 0, 0)
-        grid.addWidget(QLabel(_('{total_size} bytes').format(total_size=total_size)), 0, 1)
-        max_fee = new_tx.output_value()
-        grid.addWidget(QLabel(_('Input amount') + ':'), 1, 0)
-        grid.addWidget(QLabel(self.format_amount(max_fee) + ' ' + self.base_unit()), 1, 1)
-        output_amount = QLabel('')
-        grid.addWidget(QLabel(_('Output amount') + ':'), 2, 0)
-        grid.addWidget(output_amount, 2, 1)
-        fee_e = BTCAmountEdit(self.get_decimal_point)
-        def f(x):
-            a = max_fee - fee_e.get_amount()
-            output_amount.setText((self.format_amount(a) + ' ' + self.base_unit()) if a else '')
-        fee_e.textChanged.connect(f)
-        fee = self.config.fee_per_kb() * total_size / 1000
-        fee_e.setAmount(fee)
-        grid.addWidget(QLabel(_('Fee' + ':')), 3, 0)
-        grid.addWidget(fee_e, 3, 1)
-        def on_rate(dyn, pos, fee_rate):
-            fee = fee_rate * total_size / 1000
-            fee = min(max_fee, fee)
-            fee_e.setAmount(fee)
-        fee_slider = FeeSlider(self, self.config, on_rate)
-        fee_slider.update()
-        grid.addWidget(fee_slider, 4, 1)
-        vbox.addLayout(grid)
-        vbox.addLayout(Buttons(CancelButton(d), OkButton(d)))
-        result = d.exec_()
-        d.setParent(None) # So Python can GC
-        if not result:
-            return
-        fee = fee_e.get_amount()
-        if fee > max_fee:
-            self.show_error(_('Max fee exceeded'))
-            return
-        new_tx = self.wallet.cpfp(parent_tx, fee)
-        if new_tx is None:
-            self.show_error(_('CPFP no longer valid'))
-            return
-        self.show_transaction(new_tx)
-
     def rebuild_history(self):
         if self.gui_object.warn_if_no_network(self):
             # Don't allow if offline mode.