The `debug_assert` in `check_replace_previous_entry` is actually reachable

[tnull]

I hit this debug_assert when running LDK Server in debug mode:

rust-lightning/lightning/src/routing/utxo.rs

Lines 320 to 324 in eb3980d

	// This shouldn't actually be reachable. We set the
	// `channel_announce` field under the same lock as setting the
	// channel map entry. Still, we can just treat it as
	// non-matching and let the new request fly.
	debug_assert!(false);

[2026-02-24T08:05:10.569Z TRACE lightning::routing::gossip:2519] Updating channel 2040807930361675776 in direction 1 with timestamp 1771858779
[2026-02-24T08:05:10.569Z TRACE lightning::ln::peer_handler:2409] Received message ChannelAnnouncement(ChannelAnnouncement { node_signature_1: 304402202bdfe1db84518073f45d7c96c65138fc996911a5c107e77fd495d9b682e3ab8b02203f82b4f575acd86c0979ca1c757cff5251c18e6d8d7ae0dc8bbd424a77c8d8c7, node_signature_2: 304402201791c9202c4308e754e34c8b191ea24d122a11af194a681ad0297a5b0aec465d02206b33548a9345c819e768d15e9370ca5595c86ba652a2c603f3f791e22ae67e30, bitcoin_signature_1: 304402205e8dcc2202e7d99bc8d16d12685d30380192bf414555aa31ccfb2f3e8e0ba81b022025e69971501f12029523b462888226a24bf1a8131a1ade7fc52294774b13fce3, bitcoin_signature_2: 304402203f54bdcf1f968f0f208c968b2447fe276edafc83d704bbccd3a50b5ec85bf94b0220629d13f971a8ab49e104587fddb95c4c7418ebb0737077709e38373db8b4b210, contents: UnsignedChannelAnnouncement { features: [], chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 2197079318994157569, node_id_1: NodeId(0207655ff45578872b16bf2055720ad261ed894211ed3db82002a390e1125af20b), node_id_2: NodeId(032ae843e4d7d177f151d021ac8044b0636ec72b1ce3ffcde5c04748db2517ab03), bitcoin_key_1: NodeId(02fb433b235a82a55f33cb06163e7144f9ea1b7e48997634ecade632c44c927ecc), bitcoin_key_2: NodeId(0221253e4fa3e209312ee394938b73e5abd312cd7ae68dd02bc32d5422e8e086e1), excess_data: [] } }) (p:02465e)                                                                                                                                            
[2026-02-24T08:05:10.570Z TRACE lightning::ln::peer_handler:2050] Error handling gossip message from 02db27c3adaa8dfbd53b3bbe3ef79758e23e974e6a6a168f9726bc1722166dd04a; ignoring: Channel being checked async (p:02db27)                                                                             
[2026-02-24T08:05:10.571Z TRACE lightning::ln::peer_handler:2409] Received message ChannelAnnouncement(ChannelAnnouncement { node_signature_1: 3045022100d7acd2f16d310c7939f58065059b8348f344eb8f27eec3037227eba79916999002202b0041a9d2e30262d368c4c373c3add206594bcc81a84506871bb98b7f27aa5a, node_signature_2: 3044022016111948dbce52d5201f50371832aaab75c0d2738b891f672d6bb7178a1049ec0220081601bf070119336f2d1fc46c1895fb42c41f4ac202e6fe28f6492e93f4ac11, bitcoin_signature_1: 304502210095751de8ce463180ed881bb2680d9e65e55c023efaaf3b2fc94cd57e0ff155270220022829b5df4eef5530c6c6b88344c0c538a11cfd931399242b790130b83b1d92, bitcoin_signature_2: 304502210096ed5093cced8550a10f5a2a1b7991c57651aa44d78611444db34954404e40cf022026fe8f0835fe9679f6a9b2070c731ac8b8c3fe7e60eee915b7c85415cfa4e5e8, contents: UnsignedChannelAnnouncement { features: [], chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 1916714849027686400, node_id_1: NodeId(02465ed5be53d04fde66c9418ff14a5f2267723810176c9212b722e542dc1afb1b), node_id_2: NodeId(033e58b41411d6902e594c5a2080636007923b0971e28bc5d5071d5810d646ef51), bitcoin_key_1: NodeId(02738895faf62a4c47a4d271db644b1ad33e88b53fe895662d282595f361488e3b), bitcoin_key_2: NodeId(02c34440a7f2ca8f386504a9ae909f08a1635f91d86deeae9ac85506c390c270a2), excess_data: [] } }) (p:02db27)                                                                                                                                       
[2026-02-24T08:05:10.572Z TRACE lightning::ln::peer_handler:2050] Error handling gossip message from 02465ed5be53d04fde66c9418ff14a5f2267723810176c9212b722e542dc1afb1b; ignoring: Channel being checked async (p:02465e)                                                                           
[2026-02-24T08:05:10.573Z TRACE lightning::ln::peer_handler:2409] Received message ChannelUpdate(ChannelUpdate { signature: 3044022066a8ecf4b2b18f766f85214ace9c1cadcfd1f56ef344f0f36686e6c0902bf0190220751aa32e8ecc0ca426db7a447e6fe7e4429db46ce84cc36344b9f23c975ec6f8, contents: UnsignedChannelUpdate { chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 2197079318994157569, timestamp: 1743931416, message_flags: 1, channel_flags: 0, cltv_expiry_delta: 72, htlc_minimum_msat: 1, htlc_maximum_msat: 54000000, fee_base_msat: 1000, fee_proportional_millionths: 0, excess_data: [] } }) (p:02465e)                                                                                                     
[2026-02-24T08:05:10.573Z TRACE lightning::ln::peer_handler:2050] Error handling gossip message from 02465ed5be53d04fde66c9418ff14a5f2267723810176c9212b722e542dc1afb1b; ignoring: channel_update is older than two weeks old (p:02465e)                                                              
[2026-02-24T08:05:10.574Z TRACE lightning::ln::peer_handler:2409] Received message ChannelUpdate(ChannelUpdate { signature: 304402207d88a8728c58fc030ad9e71c825462bb7a9843356cc70a161e16fe3544dfd20202205b559808775dc523c34da4c677f04ccffdf747c63941e15e738aba14ffec6641, contents: UnsignedChannelUpdate { chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 2197079318994157569, timestamp: 1771858779, message_flags: 1, channel_flags: 3, cltv_expiry_delta: 80, htlc_minimum_msat: 1000, htlc_maximum_msat: 6000000, fee_base_msat: 1000, fee_proportional_millionths: 1, excess_data: [] } }) (p:02465e)                                                                                                   
[2026-02-24T08:05:10.574Z TRACE lightning::ln::peer_handler:2050] Error handling gossip message from 02db27c3adaa8dfbd53b3bbe3ef79758e23e974e6a6a168f9726bc1722166dd04a; ignoring: Channel being checked async (p:02db27)                                                                             
[2026-02-24T08:05:10.574Z TRACE lightning::routing::gossip:2519] Updating channel 2197079318994157569 in direction 1 with timestamp 1771858779     
[2026-02-24T08:05:10.574Z TRACE lightning::ln::peer_handler:2409] Received message ChannelUpdate(ChannelUpdate { signature: 3044022050ed708cb33693800fc4c0d5cc14f73874451fbcb087df15d1178761068c76e30220372bd666fd99e6928351bbaea6c185ca70489221495dd9689529f75c2ac1de1d, contents: UnsignedChannelUpdate { chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 1916714849027686400, timestamp: 1771857886, message_flags: 1, channel_flags: 2, cltv_expiry_delta: 80, htlc_minimum_msat: 1000, htlc_maximum_msat: 990000000000, fee_base_msat: 1000, fee_proportional_millionths: 1, excess_data: [] } }) (p:02db27)                                                                                              
[2026-02-24T08:05:10.574Z TRACE lightning::ln::peer_handler:2409] Received message ChannelAnnouncement(ChannelAnnouncement { node_signature_1: 3045022100d3033490129420f01a475fa03b40da0919ab40e3dd1007bb0b47076a18b97f7502200b09577fc603d44ae0e7a1c230b1b21d5894ff3f0512983316292c831d9d940d, node_signature_2: 304502210083b19e08460951c6a34fae08af607b8a96a3ea90d3888c94a82e79d8fcd43f2f0220072d983fe5c73adc0bd8fd57e9515a919446df4dac4d5faf01dedadfae6692e9, bitcoin_signature_1: 304402205ad6b8007ab05755ada842d88c29293e889f9577cf16df42e810e7d2b653582702202bcf54a13ce8468edfdaee7f6a96518939700dc89d5162effce5f5065e8adfac, bitcoin_signature_2: 3045022100adeaf9f1becee930771ed2e7dc0d67de8c6e7eec459e219be6efbe0a7d80158a02200ee1c55c12bdd84dfe1696f46b2701e96a6c2f2fd26a5da437c1ff5edc2590b0, contents: UnsignedChannelAnnouncement { features: [], chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 2197118901412757505, node_id_1: NodeId(032ae843e4d7d177f151d021ac8044b0636ec72b1ce3ffcde5c04748db2517ab03), node_id_2: NodeId(03fa8537530a11a39a81b8f64cc1d6b374ccd95d5df383be056e21021065a15a6e), bitcoin_key_1: NodeId(025654073c3a8019c2331727d5a2fcfcb43da95b3f83748787871cdd315dc31047), bitcoin_key_2: NodeId(02625d12fd609ac56d01b81538d8f53e7c4834e16699df25bb877a9303fb882f65), excess_data: [] } }) (p:02465e)                                                                                                                                       
[2026-02-24T08:05:10.575Z TRACE lightning::routing::gossip:2519] Updating channel 1916714849027686400 in direction 0 with timestamp 1771857886   
[2026-02-24T08:05:10.576Z TRACE lightning::ln::peer_handler:2409] Received message ChannelUpdate(ChannelUpdate { signature: 304402204bea5c170c522d10f0162ec80ba9d0faaba9a60ce83fccd24a7a4d0e737679d002202dc269563152834b70d31e855b352fd62c5dc29803d3a254543c10c91aa6ffdb, contents: UnsignedChannelUpdate { chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 1916714849027686400, timestamp: 1769646055, message_flags: 1, channel_flags: 1, cltv_expiry_delta: 80, htlc_minimum_msat: 1000, htlc_maximum_msat: 990000000000, fee_base_msat: 1000, fee_proportional_millionths: 1, excess_data: [] } }) (p:02db27)                                                                                              
[2026-02-24T08:05:10.576Z TRACE lightning::ln::peer_handler:2050] Error handling gossip message from 02db27c3adaa8dfbd53b3bbe3ef79758e23e974e6a6a168f9726bc1722166dd04a; ignoring: channel_update is older than two weeks old (p:02db27)
[2026-02-24T08:05:10.578Z TRACE lightning::ln::peer_handler:2409] Received message ChannelAnnouncement(ChannelAnnouncement { node_signature_1: 3044022024e6e7f6381ed92c63932cf8f1ea26f2dec440d62ee44a964f3132754ed1a73e02202980fd19974cf09e91a98c83f2d1ad2cf83968f23e4c8683a06d4844717a7fe7, node_signature_2: 3045022100ddf6cd602b4c14786e594437bf7ca50f2290c775831fd79bc857901f2d1b1858022078f37a4ac12dcb22cb4cf1fc9acc2ecfe005e51d63eee0d8da7f06c71ad3c088, bitcoin_signature_1: 3045022100b7b428e668298c389f055d3074342a69cb8403cf96a5b01e89997652db8bdcea022003e415841970dfdc0688b08b6417835f5e7eba58303c1ca0361ce85fa1fadf47, bitcoin_signature_2: 3045022100ff46637feed6aa232f8739c393faf6c26ae1afd7af89ab4474a83a37572eb57202202f989d40921d00a72c4b2a6635e0f49b5b7d110c127968f6d682192d2b219186, contents: UnsignedChannelAnnouncement { features: [], chain_hash: f61eee3b63a380a477a063af32b2bbc97c9ff9f01f2c4225e973988108000000, short_channel_id: 1916714849027751936, node_id_1: NodeId(02465ed5be53d04fde66c9418ff14a5f2267723810176c9212b722e542
thread 'tokio-runtime-worker' panicked at /home/tnull/.cargo/git/checkouts/rust-lightning-e47a539aa5104a91/5236dba/lightning/src/routing/utxo.rs:298:33:                                                                                                                                              assertion failed: false

The node was previously synced via Esplora, and the panic happened after restarting and switching to a bitcoind instance which wasn't done fully syncing. I'm however not sure how/if that is related at all, but (even though the panic happened a few restarts in a row) the issue seems to be gone by now.