(N.b., just a carbon-copy of the PR text for lightningnetwork/lnd#10969, for the purpose of tracking on the tapd project board.)
Problem
Custom channel coop closes can fail with: unable to process close msg: insufficient fee.
Root cause
For taproot/custom channels, ChanCloser computed the initial coop close fee (idealFeeSat) from only local+remote outputs, but the final close tx can include auxiliary extra outputs.
That mismatch can underprice the first accepted close offer (notably in taproot fast-close), causing mempool rejection and peer disconnect.
Fix
Extend coop close fee weight calculation to include optional extra outputs.
(N.b., just a carbon-copy of the PR text for lightningnetwork/lnd#10969, for the purpose of tracking on the tapd project board.)
Problem
Custom channel coop closes can fail with: unable to process close msg: insufficient fee.
Root cause
For taproot/custom channels, ChanCloser computed the initial coop close fee (idealFeeSat) from only local+remote outputs, but the final close tx can include auxiliary extra outputs.
That mismatch can underprice the first accepted close offer (notably in taproot fast-close), causing mempool rejection and peer disconnect.
Fix
Extend coop close fee weight calculation to include optional extra outputs.