lnwallet.pay_to_node: log r_tags from invoice

diff --git a/electrum/gui/qt/main_window.py b/electrum/gui/qt/main_window.py
index fe4e7fb..83b3e5c 100644
--- a/electrum/gui/qt/main_window.py
+++ b/electrum/gui/qt/main_window.py
@@ -73,7 +73,7 @@ from electrum.exchange_rate import FxThread
 from electrum.simple_config import SimpleConfig
 from electrum.logging import Logger
 from electrum.lntransport import extract_nodeid, ConnStringFormatError
-from electrum.lnaddr import lndecode
+from electrum.lnaddr import lndecode, LnAddr
 from electrum.submarine_swaps import SwapServerTransport, NostrTransport
 from electrum.fee_policy import FeePolicy
 
@@ -1746,7 +1746,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger, QtEventListener):
         grid.addWidget(QLabel(_('Text') + ':'), 8, 0)
         grid.addWidget(invoice_e, 8, 1)
         r_tags = lnaddr.get_routing_info('r')
-        r_tags = '\n'.join(repr([(x[0].hex(), format_short_id(x[1]), x[2], x[3]) for x in r]) for r in r_tags)
+        r_tags = '\n'.join(repr(r) for r in LnAddr.format_bolt11_routing_info_as_human_readable(r_tags))
         routing_e = QTextEdit(str(r_tags))
         routing_e.setReadOnly(True)
         grid.addWidget(QLabel(_("Routing Hints") + ':'), 9, 0)
diff --git a/electrum/lnaddr.py b/electrum/lnaddr.py
index a5c42c7..0316768 100644
--- a/electrum/lnaddr.py
+++ b/electrum/lnaddr.py
@@ -302,6 +302,24 @@ class LnAddr(object):
         random.shuffle(r_tags)
         return r_tags
 
+    @staticmethod
+    def format_bolt11_routing_info_as_human_readable(r_tags, *, has_explicit_r_tagtype: bool = False):
+        """Converts the node-id bytes->hex, and the SCID bytes->"AAAxBBBxCC", e.g. for logging."""
+        from .util import format_short_id
+        r_tags2 = []
+        for r_tag in r_tags:
+            if has_explicit_r_tagtype:
+                (tagtype, path) = r_tag
+                assert tagtype == "r", f"found unexpected {tagtype=}"
+            else:
+                path = r_tag
+            path2 = [
+                (edge[0].hex(), format_short_id(edge[1]), edge[2], edge[3], edge[4])
+                for edge in path]
+            r_tag2 = (tagtype, path2) if has_explicit_r_tagtype else path2
+            r_tags2.append(r_tag2)
+        return r_tags2
+
     def get_amount_msat(self) -> Optional[int]:
         if self.amount is None:
             return None
@@ -374,8 +392,7 @@ class LnAddr(object):
             'unknown_tags': self.unknown_tags,
         }
         if ln_routing_info := self.get_routing_info('r'):
-            # show the last hop of routing hints. (our invoices only have one hop)
-            d['r_tags'] = [str((a.hex(),b.hex(),c,d,e)) for a,b,c,d,e in ln_routing_info[-1]]
+            d['r_tags'] = self.format_bolt11_routing_info_as_human_readable(ln_routing_info)
         return d
 
 
diff --git a/electrum/lnworker.py b/electrum/lnworker.py
index c884659..89319f7 100644
--- a/electrum/lnworker.py
+++ b/electrum/lnworker.py
@@ -1926,6 +1926,7 @@ class LNWallet(Logger):
             f"pay_to_node starting session for RHASH={payment_hash.hex()}. "
             f"using_trampoline={self.uses_trampoline()}. "
             f"invoice_features={paysession.invoice_features.get_names()}. "
+            f"r_tags={LnAddr.format_bolt11_routing_info_as_human_readable(r_tags)}. "
             f"{amount_to_pay=} msat. {budget=}")
         if not self.uses_trampoline():
             self.logger.info(
@@ -2568,7 +2569,8 @@ class LNWallet(Logger):
         assert amount_msat is None or amount_msat > 0
         timestamp = int(time.time())
         routing_hints = self.calc_routing_hints_for_invoice(amount_msat, channels=channels)
-        self.logger.info(f"creating bolt11 invoice with routing_hints: {routing_hints}, sat: {(amount_msat or 0) // 1000}")
+        formatted_r_hints = LnAddr.format_bolt11_routing_info_as_human_readable(routing_hints, has_explicit_r_tagtype=True)
+        self.logger.info(f"creating bolt11 invoice with routing_hints: {formatted_r_hints}, sat: {(amount_msat or 0) // 1000}")
         payment_secret = self.get_payment_secret(payment_info.payment_hash)
         amount_btc = amount_msat/Decimal(COIN*1000) if amount_msat else None
         min_final_cltv_delta = payment_info.min_final_cltv_delta + MIN_FINAL_CLTV_DELTA_BUFFER_INVOICE
@@ -3914,7 +3916,7 @@ class LNWallet(Logger):
                 invoice_features = payload["invoice_features"]["invoice_features"]
                 invoice_routing_info = payload["invoice_routing_info"]["invoice_routing_info"]
                 r_tags = decode_routing_info(invoice_routing_info)
-                self.logger.info(f'r_tags {r_tags}')
+                self.logger.info(f'r_tags {LnAddr.format_bolt11_routing_info_as_human_readable(r_tags)}')
                 # TODO legacy mpp payment, use total_msat from trampoline onion
             else:
                 self.logger.info('forward_trampoline: end-to-end')
diff --git a/tests/test_bolt11.py b/tests/test_bolt11.py
index fd1884f..a900545 100644
--- a/tests/test_bolt11.py
+++ b/tests/test_bolt11.py
@@ -9,6 +9,7 @@ from electrum.segwit_addr import bech32_encode, bech32_decode
 from electrum import segwit_addr
 from electrum.lnutil import UnknownEvenFeatureBits, LnFeatures, IncompatibleLightningFeatures
 from electrum import constants
+from electrum.util import bfh, ShortID
 
 from . import ElectrumTestCase
 
@@ -169,3 +170,43 @@ class TestBolt11(ElectrumTestCase):
         lnaddr.validate_and_compare_features(LnFeatures((1 << 8) + (1 << 14) + (1 << 15)))
         with self.assertRaises(IncompatibleLightningFeatures):
             lnaddr.validate_and_compare_features(LnFeatures((1 << 8) + (1 << 14) + (1 << 16)))
+
+    def test_format_bolt11_routing_info_as_human_readable(self):
+        r_tags_expl = [
+            ['r', [(bfh('029e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255'), bfh('0102030405060708'), 1, 20, 3),
+                   (bfh('039e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255'), bfh('030405060708090a'), 2, 30, 4)]],
+            ['r', [(bfh('038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9'), bfh('f4240000000002cd'), 0, 1, 40)]],
+        ]
+        self.assertEqual(
+            [
+                ('r', [('029e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255',
+                        '66051x263430x1800', 1, 20, 3),
+                       ('039e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255',
+                        '197637x395016x2314', 2, 30, 4)]
+                 ),
+                ('r', [('038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9',
+                        '16000000x0x717', 0, 1, 40),]
+                 ),
+            ],
+            LnAddr.format_bolt11_routing_info_as_human_readable(r_tags_expl, has_explicit_r_tagtype=True))
+
+        r_tags_impl = [
+            [(bfh('029e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255'), bfh('0102030405060708'), 1, 20, 3),
+                   (bfh('039e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255'), bfh('030405060708090a'), 2, 30, 4)],
+            [(bfh('038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9'), bfh('f4240000000002cd'), 0, 1, 40)],
+        ]
+        self.assertEqual(
+            [
+                [('029e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255',
+                  '66051x263430x1800', 1, 20, 3),
+                 ('039e03a901b85534ff1e92c43c74431f7ce72046060fcf7a95c37e148f78c77255',
+                  '197637x395016x2314', 2, 30, 4)],
+                [('038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9',
+                  '16000000x0x717', 0, 1, 40),],
+            ],
+            LnAddr.format_bolt11_routing_info_as_human_readable(r_tags_impl, has_explicit_r_tagtype=False))
+
+        for has_explicit_r_tagtype in (False, True):
+            self.assertEqual(
+                [],
+                LnAddr.format_bolt11_routing_info_as_human_readable([], has_explicit_r_tagtype=has_explicit_r_tagtype))