pay fails with 0.9.0-rc2

[rustyrussell]

Issue and Steps to Reproduce

Spark payment of 25,000 sat.

2020-07-19T02:04:43.987Z DEBUG plugin-manager: started(2100) /home/rusty/lightning/lightningd/../plugins/pay
2020-07-19T02:04:44.943Z DEBUG plugin-manager: started(2106) /home/rusty/.lightning/plugins/listpayments.py
2020-07-19T02:59:27.600Z INFO plugin-pay: Split into 3 sub-payments due to initial size (25000000msat > 10000000msat)
2020-07-19T03:09:10.168Z INFO plugin-pay: Split into 3 sub-payments due to initial size (25000000msat > 10000000msat)
2020-07-19T03:09:10.314Z INFO plugin-pay: Split into 3 sub-payments due to initial size (25000000msat > 10000000msat)
2020-07-19T03:09:10.365Z INFO plugin-pay: Split into 3 sub-payments due to initial size (25000000msat > 10000000msat)
2020-07-19T03:09:10.479Z INFO plugin-pay: Split into 3 sub-payments due to initial size (25000000msat > 10000000msat)
2020-07-19T03:16:47.397Z UNUSUAL plugin-pay: Unable to parse `waitsendpay` result: {\"code\":209,\"message\":\"Payment failure reason unknown\"}
2020-07-19T03:16:47.403Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/2
2020-07-19T03:25:20.604Z UNUSUAL plugin-pay: Unable to parse `waitsendpay` result: {\"code\":209,\"message\":\"Payment failure reason unknown\"}
2020-07-19T03:25:20.609Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/1
2020-07-19T03:25:20.610Z UNUSUAL plugin-pay: Unable to parse `waitsendpay` result: {\"code\":209,\"message\":\"Payment failure reason unknown\"}
2020-07-19T03:25:20.615Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/3
2020-07-19T03:25:23.897Z INFO plugin-pay: failed: WIRE_TEMPORARY_CHANNEL_FAILURE (reply from remote)
2020-07-19T03:25:23.898Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/2
2020-07-19T03:25:23.940Z INFO plugin-pay: failed: WIRE_TEMPORARY_CHANNEL_FAILURE (reply from remote)
2020-07-19T03:25:23.942Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/2
2020-07-19T03:25:23.955Z UNUSUAL plugin-pay: Unable to parse `waitsendpay` result: {\"code\":209,\"message\":\"Payment failure reason unknown\"}
2020-07-19T03:25:23.969Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/2
2020-07-19T03:25:24.035Z UNUSUAL plugin-pay: Unable to parse `waitsendpay` result: {\"code\":209,\"message\":\"Payment failure reason unknown\"}
2020-07-19T03:25:24.060Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/2
2020-07-19T03:25:29.874Z INFO plugin-pay: failed: WIRE_TEMPORARY_CHANNEL_FAILURE (reply from remote)
2020-07-19T03:25:29.961Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/3
2020-07-19T03:25:29.962Z INFO plugin-pay: failed: WIRE_TEMPORARY_CHANNEL_FAILURE (reply from remote)
2020-07-19T03:25:29.964Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/3
2020-07-19T03:25:29.971Z INFO plugin-pay: failed: WIRE_TEMPORARY_CHANNEL_FAILURE (reply from remote)
2020-07-19T03:25:29.972Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/3
2020-07-19T03:25:29.973Z INFO plugin-pay: failed: WIRE_TEMPORARY_CHANNEL_FAILURE (reply from remote)
2020-07-19T03:25:29.974Z INFO plugin-pay: Payment deadline expired, not retrying (partial-)payment 0937cf5eb3ddce160b9b3f3325b15df096938f4dab68022059fe5bc5acee0d76/3
2020-07-19T03:25:46.070Z INFO plugin-pay: Killing plugin: Plugin exited before completing handshake.

Valgrind errors (just first two)

==2100== Conditional jump or move depends on uninitialised value(s)
==2100==    at 0x11BD4F: payment_finished (libplugin-pay.c:1105)
==2100==    by 0x11B884: payment_child_finished (libplugin-pay.c:1006)
==2100==    by 0x11C0B2: payment_finished (libplugin-pay.c:1183)
==2100==    by 0x11C20C: payment_continue (libplugin-pay.c:1230)
==2100==    by 0x11EE5F: adaptive_splitter_cb (libplugin-pay.c:2252)
==2100==    by 0x11C197: payment_continue (libplugin-pay.c:1210)
==2100==    by 0x11C6BF: retry_step_cb (libplugin-pay.c:1369)
==2100==    by 0x11C197: payment_continue (libplugin-pay.c:1210)
==2100==    by 0x11E69B: waitblockheight_cb (libplugin-pay.c:2031)
==2100==    by 0x11C197: payment_continue (libplugin-pay.c:1210)
==2100==    by 0x11D7C3: routehint_step_cb (libplugin-pay.c:1658)
==2100==    by 0x11C197: payment_continue (libplugin-pay.c:1210)
==2100== 
==2100== Conditional jump or move depends on uninitialised value(s)
==2100==    at 0x544E96A: vfprintf (vfprintf.c:1642)
==2100==    by 0x547A97F: vsnprintf (vsnprintf.c:114)
==2100==    by 0x155C99: do_vfmt (str.c:66)
==2100==    by 0x155D7F: tal_vfmt_ (str.c:92)
==2100==    by 0x155BE8: tal_fmt_ (str.c:44)
==2100==    by 0x11BD84: payment_finished (libplugin-pay.c:1105)
==2100==    by 0x11B884: payment_child_finished (libplugin-pay.c:1006)
==2100==    by 0x11C0B2: payment_finished (libplugin-pay.c:1183)
==2100==    by 0x11C20C: payment_continue (libplugin-pay.c:1230)
==2100==    by 0x11EE5F: adaptive_splitter_cb (libplugin-pay.c:2252)
==2100==    by 0x11C197: payment_continue (libplugin-pay.c:1210)
==2100==    by 0x11C6BF: retry_step_cb (libplugin-pay.c:1369)

Crash:

pay: plugins/libplugin-pay.c:702: payment_waitsendpay_finished: Assertion `*p->result->erring_index < tal_count(p->route)' failed.
pay: FATAL SIGNAL 6 (version v0.9.0rc2)
0x12e0cf send_backtrace
	common/daemon.c:38
0x12e175 crashdump
	common/daemon.c:51
0x5430fcf ???
	???:0
0x5430f47 ???
	???:0
0x54328b0 ???
	???:0
0x5422429 ???
	???:0
0x54224a1 ???
	???:0
0x11a970 payment_waitsendpay_finished
	plugins/libplugin-pay.c:702
0x114b2b handle_rpc_reply
	plugins/libplugin.c:539
0x115236 rpc_read_response_one
	plugins/libplugin.c:662
0x115327 rpc_conn_read_response
	plugins/libplugin.c:681
0x146a63 next_plan
	ccan/ccan/io/io.c:59
0x1475e0 do_plan
	ccan/ccan/io/io.c:407
0x14761e io_ready
	ccan/ccan/io/io.c:417
0x1497e4 io_loop
	ccan/ccan/io/poll.c:445
0x1174bb plugin_main
	plugins/libplugin.c:1284
0x113777 main
	plugins/pay.c:2010
0x5413b96 ???
	???:0
0x10cc69 ???
	???:0
0xffffffffffffffff ???
	???:0

getinfo output

{
   "id": "024b9a1fa8e006f1e3937f65f66c408e6da8e1ca728ea43222a7381df1cc449605",
   "alias": "BLUEIRON-v0.9.0rc2",
   "color": "024b9a",
   "num_peers": 31,
   "num_pending_channels": 0,
   "num_active_channels": 31,
   "num_inactive_channels": 0,
   "address": [
      {
         "type": "ipv4",
         "address": "128.199.202.168",
         "port": 9735
      },
      {
         "type": "ipv6",
         "address": "2400:6180:0:d0::5cd2:a001",
         "port": 9735
      },
      {
         "type": "torv3",
         "address": "ki5uack5xb4gicfnpfavzdibojfu3qvwtlg3ca7eyjxik7tgwfxummqd.onion",
         "port": 9735
      },
      {
         "type": "torv3",
         "address": "3kwzm4b4qgzafj4fkicsdjpptkgtohojdby2tyybmlf44t5xug7kqrqd.onion",
         "port": 9735
      }
   ],
   "binding": [
      {
         "type": "ipv6",
         "address": "::",
         "port": 9735
      },
      {
         "type": "ipv4",
         "address": "0.0.0.0",
         "port": 9735
      }
   ],
   "version": "v0.9.0rc2",
   "blockheight": 639834,
   "network": "bitcoin",
   "msatoshi_fees_collected": 304561,
   "fees_collected_msat": "304561msat",
   "lightning-dir": "/home/rusty/.lightning/bitcoin"