tests: test reproduce #8847

[enaples]

Important

26.04 FREEZE March 11th: Non-bugfix PRs not ready by this date will wait for 26.06.

RC1 is scheduled on March 23rd

The final release is scheduled for April 15th.

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• The changelog has been updated in the relevant commit(s) according to the guidelines.
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Additional info

Test to reproduce #8847

uv run python -m pytest -vvvv tests/test_opening.py::test_opening_dualfund_with_unknown_feerates

Unfortunately I cannot continue the test after BROKEN message. I was able to reproduce the issue on signet and I can can confirm that the error message after crash are the same pointed out in the issue.

I report logs for completeness:

lightningd: common/fee_states.c:175: marginal_feerate: Assertion `current_feerate >= minfeerate' failed.

lightningd: FATAL SIGNAL 6 (version v25.12)

0xaaaad9c1a477 send_backtrace
	common/daemon.c:38

0xaaaad9c1a523 crashdump

	common/daemon.c:83

0xffff9dbed7cf ???

	???:0

0xffff9d717608 __pthread_kill_implementation

	./nptl/pthread_kill.c:44

0xffff9d6ccb3b __GI_raise

	../sysdeps/posix/raise.c:26

0xffff9d6b7dff __GI_abort

	./stdlib/abort.c:79

0xffff9d6c5cbf __assert_fail_base

	./assert/assert.c:96

0xffff9d6c5d2f __assert_fail

	./assert/assert.c:105

0xaaaad9c1c8a7 marginal_feerate

	common/fee_states.c:175

0xaaaad9ba149b commit_txfee

	lightningd/peer_control.c:747

0xaaaad9ba5d9b channel_amount_spendable

	lightningd/peer_control.c:814

0xaaaad9ba6997 json_add_channel

	lightningd/peer_control.c:1222

0xaaaad9ba6fe3 json_add_peerchannels

	lightningd/peer_control.c:2621

0xaaaad9ba71bf json_listpeerchannels

	lightningd/peer_control.c:2662

0xaaaad9b802d3 command_exec

	lightningd/jsonrpc.c:769
0xaaaac3972517 rpc_command_hook_final

	lightningd/jsonrpc.c:910

0xaaaac39a7b7b hook_done

	lightningd/plugin_hook.c:243

0xaaaac39a7caf plugin_hook_call_next

	lightningd/plugin_hook.c:343

0xaaaac39a8983 plugin_hook_call_

	lightningd/plugin_hook.c:395

0xaaaac3972c4b plugin_hook_call_rpc_command

	lightningd/jsonrpc.c:998

0xaaaac3972c4b parse_request

	lightningd/jsonrpc.c:1122

0xaaaac3972fcb read_json

	lightningd/jsonrpc.c:1216

0xaaaac3a51d47 next_plan

	ccan/ccan/io/io.c:60

0xaaaac3a5231b do_plan

	ccan/ccan/io/io.c:422

0xaaaac3a523f3 io_ready

	ccan/ccan/io/io.c:439

0xaaaac3a543bf io_loop

	ccan/ccan/io/poll.c:470

0xaaaac39701d3 io_loop_with_timers

	lightningd/io_loop_with_timers.c:22

0xaaaac39a5837 plugins_config

	lightningd/plugin.c:2237

0xaaaac3975e6f main

	lightningd/lightningd.c:1396

0xffff7fea84c3 __libc_start_call_main

	../sysdeps/nptl/libc_start_call_main.h:58

0xffff7fea8597 __libc_start_main_impl

	../csu/libc-start.c:360

0xaaaac39431ef ???

	_start+0x2f:0

0xffffffffffffffff ???

	???:0

Lost connection to the RPC socket.Reading sync lightningd: Connection reset by peerReading sync lightningd: Connection reset by peer

From crash.log I get:

+8983.404577377 lightningdDEBUG: Unable to estimate any fees
+9012.664302501 jsonrpc#50IO_IN: 7b226a736f6e727063223a22322e30222c226964223a2274696d65722f7265636f7665723a6c697374706565726368616e6e656c73233237222c226d6574686f64223a226c697374706565726368616e6e656c73222c22706172616d73223a7b7d7d0a0a
+9012.664657543 jsonrpc#50IO_IN: "timer/recover:listpeerchannels#27"
+9012.781892001 lightningdBROKEN: FATAL SIGNAL 6 (version v25.12)
+9012.782006793 lightningdBROKEN: backtrace: common/daemon.c:46 (send_backtrace) 0xaaaacc08a4c3
+9012.782011335 lightningdBROKEN: backtrace: common/daemon.c:83 (crashdump) 0xaaaacc08a523
+9012.782013460 lightningdBROKEN: backtrace: (null):0 ((null)) 0xffff8a8177cf
+9012.782015626 lightningdBROKEN: backtrace: ./nptl/pthread_kill.c:44 (__pthread_kill_implementation) 0xffff8a347608
+9012.782017335 lightningdBROKEN: backtrace: ../sysdeps/posix/raise.c:26 (__GI_raise) 0xffff8a2fcb3b
+9012.782018876 lightningdBROKEN: backtrace: ./stdlib/abort.c:79 (__GI_abort) 0xffff8a2e7dff
+9012.782020585 lightningdBROKEN: backtrace: ./assert/assert.c:96 (__assert_fail_base) 0xffff8a2f5cbf
+9012.782021918 lightningdBROKEN: backtrace: ./assert/assert.c:105 (__assert_fail) 0xffff8a2f5d2f
+9012.782023501 lightningdBROKEN: backtrace: common/fee_states.c:175 (marginal_feerate) 0xaaaacc08c8a7
+9012.782025293 lightningdBROKEN: backtrace: lightningd/peer_control.c:747 (commit_txfee) 0xaaaacc01149b
+9012.782027501 lightningdBROKEN: backtrace: lightningd/peer_control.c:814 (channel_amount_spendable) 0xaaaacc015d9b
+9012.782029918 lightningdBROKEN: backtrace: lightningd/peer_control.c:1222 (json_add_channel) 0xaaaacc016997
+9012.782031168 lightningdBROKEN: backtrace: lightningd/peer_control.c:2621 (json_add_peerchannels) 0xaaaacc016fe3
+9012.782047793 lightningdBROKEN: backtrace: lightningd/peer_control.c:2662 (json_listpeerchannels) 0xaaaacc0171bf
+9012.782050168 lightningdBROKEN: backtrace: lightningd/jsonrpc.c:769 (command_exec) 0xaaaacbff02d3
+9012.782051918 lightningdBROKEN: backtrace: lightningd/jsonrpc.c:910 (rpc_command_hook_final) 0xaaaacbff2517
+9012.782053293 lightningdBROKEN: backtrace: lightningd/plugin_hook.c:243 (hook_done) 0xaaaacc027b7b
+9012.782054376 lightningdBROKEN: backtrace: lightningd/plugin_hook.c:343 (plugin_hook_call_next) 0xaaaacc027caf
+9012.782055501 lightningdBROKEN: backtrace: lightningd/plugin_hook.c:395 (plugin_hook_call_) 0xaaaacc028983
+9012.782057168 lightningdBROKEN: backtrace: lightningd/jsonrpc.c:998 (plugin_hook_call_rpc_command) 0xaaaacbff2c4b
+9012.782058001 lightningdBROKEN: backtrace: lightningd/jsonrpc.c:1122 (parse_request) 0xaaaacbff2c4b
+9012.782059418 lightningdBROKEN: backtrace: lightningd/jsonrpc.c:1216 (read_json) 0xaaaacbff2fcb
+9012.782060668 lightningdBROKEN: backtrace: ccan/ccan/io/io.c:60 (next_plan) 0xaaaacc0d1d47
+9012.782061751 lightningdBROKEN: backtrace: ccan/ccan/io/io.c:422 (do_plan) 0xaaaacc0d231b
+9012.782064460 lightningdBROKEN: backtrace: ccan/ccan/io/io.c:439 (io_ready) 0xaaaacc0d23f3
+9012.782067585 lightningdBROKEN: backtrace: ccan/ccan/io/poll.c:470 (io_loop) 0xaaaacc0d43bf
+9012.782068751 lightningdBROKEN: backtrace: lightningd/io_loop_with_timers.c:22 (io_loop_with_timers) 0xaaaacbff01d3
+9012.782070043 lightningdBROKEN: backtrace: lightningd/lightningd.c:1492 (main) 0xaaaacbff6217
+9012.782071210 lightningdBROKEN: backtrace: ../sysdeps/nptl/libc_start_call_main.h:58 (__libc_start_call_main) 0xffff8a2e84c3
+9012.782072418 lightningdBROKEN: backtrace: ../csu/libc-start.c:360 (__libc_start_main_impl) 0xffff8a2e8597
+9012.782073460 lightningdBROKEN: backtrace: (null):0 ((null)) 0xaaaacbfc31ef
+9012.782074460 lightningdBROKEN: backtrace: (null):0 ((null)) 0xffffffffffffffff