[bug]: possible flake in lnwallet/chancloser unit test

[calvinrzachman]

Pre-Submission Checklist

• I have searched the existing issues and believe this is a new bug.
• I am not asking a question about how to use lnd, but reporting a bug (otherwise open a discussion).

LND Version

v0.20.0-beta

LND Configuration

The issue is with a unit test so I don't think lnd.conf is applicable.

Backend Version

Bitcoin Core v29.0.0

Backend Configuration

The issue is with a unit test so I don't think bitcoin.conf is applicable.

OS/Distribution

Ubuntu 24.04.3 LTS

Bug Details & Steps to Reproduce

Noticed a failing unit test unrelated to the change set made in a PR. Figured that it may be a flake. The issue was observed on the CI test runner, but the tests can be ran locally with make unit-debug tags="kvdb_postgres" pkg=lnwallet/chancloser

Expected Behavior

The unit test should pass.

Debug Information

The CI run failed with a panic during unit tests for the lnwallet/chancloser package. The specific error observed can be seen in the stack trace:

panic: assert: arguments: Cannot call Get(0) because there are 0 argument(s).

goroutine 227 [running]:
github.com/stretchr/testify/mock.Arguments.Get(...)
	/home/runner/go/pkg/mod/github.com/stretchr/testify@v1.10.0/mock/mock.go:926
github.com/lightningnetwork/lnd/lnwallet/chancloser.(*mockCloseSigner).CreateCloseProposal(0xc000587d60, 0x2774, {0xc000041110, 0x22, 0x30}, {0xc000041230, 0x22, 0x30}, {0xc0000138d8, 0x3, ...})
	/home/runner/work/lnd/lnd/lnwallet/chancloser/mock.go:183 +0x45c
github.com/lightningnetwork/lnd/lnwallet/chancloser.(*RemoteCloseStart).ProcessEvent(0xc0007cdbc8?, {0x103d4a0?, 0xc0004ca900}, 0xc0007e8388)
	/home/runner/work/lnd/lnd/lnwallet/chancloser/rbf_coop_transitions.go:1049 +0x6fd
github.com/lightningnetwork/lnd/lnwallet/chancloser.processNegotiateEvent(0xc0004b1560, {0x103d4a0?, 0xc0004ca900?}, 0xc000273f60?, 0x1)
	/home/runner/work/lnd/lnd/lnwallet/chancloser/rbf_coop_transitions.go:586 +0x5b
github.com/lightningnetwork/lnd/lnwallet/chancloser.(*ClosingNegotiation).ProcessEvent(0xc0004b1560, {0x103d4a0, 0xc0004ca900}, 0xc0007e8388)
	/home/runner/work/lnd/lnd/lnwallet/chancloser/rbf_coop_transitions.go:727 +0x3ba
github.com/lightningnetwork/lnd/protofsm.(*StateMachine[...]).applyEvents.func1(...)
	/home/runner/work/lnd/lnd/protofsm/state_machine.go:586
github.com/lightningnetwork/lnd/fn/v2.MapOptionZ[...](...)
	/home/runner/go/pkg/mod/github.com/lightningnetwork/lnd/fn/v2@v2.0.9/option.go:185
github.com/lightningnetwork/lnd/protofsm.(*StateMachine[...]).applyEvents(0x105dd20, {0x1048070, 0xc000587e50}, {0x1044c38, 0xc0007b0960}, {0x103d540, 0xc00003d260})
	/home/runner/work/lnd/lnd/protofsm/state_machine.go:580 +0x26f
github.com/lightningnetwork/lnd/protofsm.(*StateMachine[...]).driveMachine(0x105dd20, {0x1048070, 0xc000587e50})
	/home/runner/work/lnd/lnd/protofsm/state_machine.go:674 +0x337
github.com/lightningnetwork/lnd/protofsm.(*StateMachine[...]).Start.func1.1()
	/home/runner/work/lnd/lnd/protofsm/state_machine.go:229 +0x35
github.com/lightningnetwork/lnd/fn/v2.(*GoroutineManager).Go.func1()
	/home/runner/go/pkg/mod/github.com/lightningnetwork/lnd/fn/v2@v2.0.9/goroutine_manager.go:122 +0x59
created by github.com/lightningnetwork/lnd/fn/v2.(*GoroutineManager).Go in goroutine [208](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:9:209)
	/home/runner/go/pkg/mod/github.com/lightningnetwork/lnd/fn/v2@v2.0.9/goroutine_manager.go:116 +0x219
FAIL	github.com/lightningnetwork/lnd/lnwallet/chancloser	1.693s
FAIL

Example: https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489

Environment

Environment:

• The issue is observed within lnd repo GitHub Actions CI Runner.
• Go Version: 1.25.3
• Bitcoin Version: 29
• Command: make unit tags="kvdb_postgres"
• Affected Package: github.com/lightningnetwork/lnd/lnwallet/chancloser

Current runner version: '2.330.0'
Runner Image Provisioner
  Hosted Compute Agent
  Version: [2](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:1:2)0251211.462
  Commit: 6cbad8c2bb55d5816506[3](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:1:3)d031ccabf57e2d2db61
  Build Date: 2025-12-11T16:28:[4](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:1:4)9Z
  Worker ID: {4c2ea6bb-1d[5](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:1:5)7-4eb7-942e-bc3fda4b4476}
Operating System
  Ubuntu
  24.04.3
  LTS
Runner Image
  Image: ubuntu-24.04
  Version: 20251215.1[7](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:1:7)4.1
  Included Software: https://github.com/actions/runner-images/blob/ubuntu24/20251215.174/images/ubuntu/Ubuntu2404-Readme.md
  Image Release: https://github.com/actions/runner-images/releases/tag/ubuntu24%2F2025[12](https://github.com/lightningnetwork/lnd/actions/runs/20469413158/job/58821008486?pr=9489#step:1:14)15.174