Unable to keep channel open after upgrading to master

[hMsats]

Trying to connect my test node (v25.09rc1-3-g7c75abc) to my main node (v25.05, id: 031979fe...) gives the error below. Luckily, my test node didn't close the channel.
After returning to v25.05 (test node v25.05 software plus a backup of the test node data in .lightning) everything works fine again.
I tried a few times to reconnect therefore the repeated error messages:

2025-08-21T06:48:04.424Z INFO    lightningd: v25.09rc1-3-g7c75abc
2025-08-21T06:48:04.499Z INFO    plugin-manager: /home/user/lightning_test/plugins/bookkeeper: disabled via disable-plugin
2025-08-21T06:48:04.759Z INFO    lightningd: Updating database from version 268 to 276
2025-08-21T06:48:04.932Z INFO    lightningd: bookkeeper migration complete: migrated 23 chainmoves, 1115 channelmoves, 878 descriptions
2025-08-21T06:48:04.946Z INFO    plugin-backup.py: root        : Comparing backup version 734788 versus first write version 734789
2025-08-21T06:48:04.946Z INFO    plugin-backup.py: Comparing backup version 734788 versus first write version 734789
2025-08-21T06:48:04.946Z INFO    plugin-backup.py: root        : Versions match up
2025-08-21T06:48:04.946Z INFO    plugin-backup.py: Versions match up
2025-08-21T06:48:17.045Z INFO    plugin-bcli: bitcoin-cli initialized and connected to bitcoind.
2025-08-21T06:48:19.068Z INFO    plugin-chanbackup: Loaded 1 stored backups for peers
2025-08-21T06:48:19.301Z INFO    lightningd: --------------------------------------------------
2025-08-21T06:48:19.301Z INFO    lightningd: Server started with public key 02a9dbc1724ecdcd94364920c029cc5b260081d5148d6698328f8dc73b3bfa0fcd, alias shecret (color #02a9db) and lightningd v25.09rc1-3-g7c75abc
2025-08-21T06:50:38.242Z INFO    plugin-cln-xpay: Redirecting pay->xpay
2025-08-21T06:50:38.519Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:50:38.537Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:50:38.537Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:50:40.323Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:50:40.323Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:50:40.323Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:50:43.326Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:50:43.327Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:50:43.327Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:50:47.499Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:50:47.500Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:50:47.500Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:50:56.301Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:50:56.301Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:50:56.301Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:51:10.667Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:51:10.668Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:51:10.669Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:51:12.752Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:51:12.752Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:51:12.752Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:51:45.769Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:51:45.841Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:51:45.841Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:52:01.698Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:52:01.705Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:52:01.705Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:52:15.391Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:52:15.391Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:52:15.391Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:52:50.449Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:52:50.452Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:52:50.452Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:54:23.783Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:54:23.783Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:54:23.783Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:54:55.313Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:54:55.313Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:54:55.313Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:54:58.815Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:54:58.815Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:54:58.816Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:58:40.191Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:58:40.212Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:58:40.212Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T06:59:15.611Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T06:59:15.611Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T06:59:15.611Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T07:01:33.697Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Received WARNING channel 00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124: Bad commit_sig 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e
2025-08-21T07:01:33.700Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-channeld-chan#3: Peer connection lost
2025-08-21T07:01:33.700Z INFO    031979fe6ce0e69ece6d99a4bc4a7b30ed22a8cb8703dd7dd2dfaf619e07127e0b-chan#3: Peer transient failure in CHANNELD_NORMAL: channeld: Owning subdaemon channeld died (62208)
2025-08-21T07:01:53.773Z UNUSUAL lightningd: JSON-RPC shutdown                                                                                                                                                                                                                            

[rustyrussell]

Looks like a change in the experimental splicing code may have introduced an incompatibility? That sucks, but it's also not terribly surprising if you're in the process of splicing? Or perhaps have an old, unfinished splice?

[rustyrussell]

If not currently splicing, you may have to upgrade both at once :( @ddustin ?

[hMsats]

I indeed did a splice in June between my main node and test node. I thought that after a splice, all the data in the database are the same as if the splice never happened, except for the updated channel balances. However, I took the risk and upgraded both lightning nodes (to v25.09rc1-3-g7c75abc) and fortunately it worked well and the issue is now gone. Thanks for the suggestion!

[ddustin]

% ./devtools/decodemsg 008400e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f227cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6000000205c03e880dc44fdae15fca3bd6e39fe8ab437613a90cb7075db31b0999481af3e

WIRE_COMMITMENT_SIGNED:
 channel_id=00e8fa5f98228486a276abaa8e970d3b8433ff8afc7950f78973e5ead9078124
 signature=30440220246fb1c6c36169d783489a90d69ee6a6511ade0d5871f2cacda6e336f66a6f2202207cf2cf7bb406374a20c998d51bac6a13a4bc0d1ea253b7ac208999bdd1638dd6
 htlc_signature=[]
 splice_channel_id={
  type=0
  len=32
  (msg_name=splice_info)
   funding_txid=3eaf819499b031db7570cb903a6137b48afe396ebda3fc15aefd44dc80e8035c
 }

This looks like [v25.09] is sending [v25.05] WIRE_COMMITMENT_SIGNED without the batch_size value in tlv (it was removed by tbast's start_batch update), causing fromwire_commitment_signed to fail.

I thought the tlv fields were always optional but something is causing [v25.05] to require batch_size if the tlv is present.

By my read this will only happen if you have splicing enabled on both nodes (and the feature is negotiated) -- as the tlv isn't sent otherwise.

Part of the problem might be the tlv type being set to 0 instead of 1 as the rules for even types are stricter.

tlvtype,commitment_signed_tlvs,splice_info,0
tlvdata,commitment_signed_tlvs,splice_info,funding_txid,sha256,

Tbast's spec:

1. `tlv_stream`: `commitment_signed_tlvs`
2. types:
   1. type: 1 (`funding_txid`)
   2. data:
     * [`sha256`:`funding_txid`]

[ddustin]

Not clear if solving the tlv type issue will fix the problem experienced by the OP but here's a PR that updates the commitment_signed_tlvs type: #8506

Best I can tell the OP's issue should only occur if splicing is enabled, as commitment_signed_tlvs are only sent if splicing is enabled.