qt preferences: always show cb for LN/"Create recoverable channels"

This makes it explicit that the option cannot be enabled if so (instead of hiding the checkbox).

electrum/gui/kivy/uix/dialogs/settings.py

@@ -136,7 +136,7 @@ def update(self):
         self.wallet = self.app.wallet
         self.use_encryption = self.wallet.has_password() if self.wallet else False
         self.has_pin_code = self.app.has_pin_code()
-        self.enable_toggle_use_recoverable_channels = bool(self.wallet.lnworker and self.wallet.lnworker.has_deterministic_node_id())
+        self.enable_toggle_use_recoverable_channels = bool(self.wallet.lnworker and self.wallet.lnworker.can_have_recoverable_channels())
 
     def get_language_name(self) -> str:
         lang = self.config.get('language') or ''

electrum/gui/qt/settings_dialog.py

@@ -129,16 +129,16 @@ def on_batch_rbf(x):
         # lightning
         lightning_widgets = []
 
-        if self.wallet.lnworker and self.wallet.lnworker.has_deterministic_node_id():
-            help_recov = _(messages.MSG_RECOVERABLE_CHANNELS)
-            recov_cb = QCheckBox(_("Create recoverable channels"))
-            recov_cb.setToolTip(messages.to_rtf(help_recov))
-            recov_cb.setChecked(bool(self.config.get('use_recoverable_channels', True)))
-            def on_recov_checked(x):
-                self.config.set_key('use_recoverable_channels', bool(x))
-            recov_cb.stateChanged.connect(on_recov_checked)
-            recov_cb.setEnabled(not bool(self.config.get('lightning_listen')))
-            lightning_widgets.append((recov_cb, None))
+        help_recov = _(messages.MSG_RECOVERABLE_CHANNELS)
+        recov_cb = QCheckBox(_("Create recoverable channels"))
+        enable_toggle_use_recoverable_channels = bool(self.wallet.lnworker and self.wallet.lnworker.can_have_recoverable_channels())
+        recov_cb.setEnabled(enable_toggle_use_recoverable_channels)
+        recov_cb.setToolTip(messages.to_rtf(help_recov))
+        recov_cb.setChecked(bool(self.config.get('use_recoverable_channels', True)) and enable_toggle_use_recoverable_channels)
+        def on_recov_checked(x):
+            self.config.set_key('use_recoverable_channels', bool(x))
+        recov_cb.stateChanged.connect(on_recov_checked)
+        lightning_widgets.append((recov_cb, None))
 
         help_trampoline = _(messages.MSG_HELP_TRAMPOLINE)
         trampoline_cb = QCheckBox(_("Use trampoline routing (disable gossip)"))

electrum/lnworker.py

@@ -650,14 +650,19 @@ def __init__(self, wallet: 'Abstract_Wallet', xprv):
         # map forwarded htlcs (fw_info=(scid_hex, htlc_id)) to originating peer pubkeys
         self.downstream_htlc_to_upstream_peer_map = {}  # type: Dict[Tuple[str, int], bytes]
 
-    def has_deterministic_node_id(self):
+    def has_deterministic_node_id(self) -> bool:
         return bool(self.db.get('lightning_xprv'))
 
-    def has_recoverable_channels(self):
-        # TODO: expose use_recoverable_channels in preferences
-        return self.has_deterministic_node_id() \
-            and self.config.get('use_recoverable_channels', True) \
-            and not (self.config.get('lightning_listen'))
+    def can_have_recoverable_channels(self) -> bool:
+        return (self.has_deterministic_node_id()
+                and not (self.config.get('lightning_listen')))
+
+    def has_recoverable_channels(self) -> bool:
+        """Whether *future* channels opened by this wallet would be recoverable
+        from seed (via putting OP_RETURN outputs into funding txs).
+        """
+        return (self.can_have_recoverable_channels()
+                and self.config.get('use_recoverable_channels', True))
 
     @property
     def channels(self) -> Mapping[bytes, Channel]: