nats audit analyze crash

[jtnats]

Observed behavior

I am observing a crash when running: nats audit analyze file.zip

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x8 pc=0x1053376dc]

goroutine 1 [running]:
github.com/nats-io/jsm.go/audit.checkServerHealth.func1(0x105bea868?, 0x14000096520, {0x105bea868?, 0x14000430640?}, 0x0)
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/server_checks.go:143 +0x5c
github.com/nats-io/jsm.go/audit/archive.(*Reader).EachClusterServerHealthz.func1(0x105bea868?, 0x14000430640?, {0x105bea868?, 0x14000430640?}, 0x1059cbaa0?)
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/archive/reader.go:399 +0x2c
github.com/nats-io/jsm.go/audit/archive.EachClusterServerArtifact[...](0x14000228460, 0x1400004b3d8, 0x1400004b3c8)
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/archive/reader.go:462 +0x320
github.com/nats-io/jsm.go/audit/archive.(*Reader).EachClusterServerHealthz(0x14000401808?, 0x1400123fb60?)
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/archive/reader.go:398 +0x64
github.com/nats-io/jsm.go/audit.checkServerHealth(0x20?, 0x6?, 0x1400123fb60, {0x105bf4c40, 0x140003c6420})
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/server_checks.go:138 +0x40
github.com/nats-io/jsm.go/audit.runCheck(0x14000438b40, 0x14000228460, 0x5, {0x105bf4c40, 0x140003c6420})
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/checks.go:248 +0x84
github.com/nats-io/jsm.go/audit.(*CheckCollection).Run.func1(0x14000438b40)
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/checks.go:318 +0x1c4
github.com/nats-io/jsm.go/audit.(*CheckCollection).EachCheck(0x14000438550, 0x1400004b888)
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/checks.go:277 +0x32c
github.com/nats-io/jsm.go/audit.(*CheckCollection).Run(0x14000438550, 0x14000228460, 0x5, {0x105bf4c40, 0x140003c6420})
	/home/runner/go/pkg/mod/github.com/nats-io/jsm.go@v0.3.1-0.20260116154816-a772222ebcf0/audit/checks.go:307 +0x2ac
github.com/nats-io/natscli/cli.(*auditAnalyzeCmd).analyze(0x14000580000, 0x10520ca10?)
	/home/runner/work/natscli/natscli/cli/audit_analyze_command.go:103 +0x1d8
github.com/choria-io/fisk.(*actionMixin).applyActions(...)
	/home/runner/go/pkg/mod/github.com/choria-io/fisk@v0.7.2/actions.go:28
github.com/choria-io/fisk.(*Application).applyActions(0x14000136000?, 0x14000126120)
	/home/runner/go/pkg/mod/github.com/choria-io/fisk@v0.7.2/app.go:812 +0xe4
github.com/choria-io/fisk.(*Application).execute(0x14000136000, 0x14000126120, {0x140005902e0, 0x2, 0x2})
	/home/runner/go/pkg/mod/github.com/choria-io/fisk@v0.7.2/app.go:613 +0x50
github.com/choria-io/fisk.(*Application).Parse(0x14000136000, {0x14000032090?, 0x1400004bb78?, 0x2c?})
	/home/runner/go/pkg/mod/github.com/choria-io/fisk@v0.7.2/app.go:276 +0x108
github.com/choria-io/fisk.(*Application).MustParseWithUsage(0x14000136000, {0x14000032090, 0x3, 0x3})
	/home/runner/go/pkg/mod/github.com/choria-io/fisk@v0.7.2/app.go:878 +0x34
main.main()
	/home/runner/work/natscli/natscli/nats/main.go:87 +0x2a94

Expected behavior

The expected output as seen on other non-problematic zip files.

Server and client version

• Server Version: 2.12.6
• Creator: nats 0.3.1

Host environment

• nats cli running on MacOS 26.3.1

Steps to reproduce

$ uname -a
Darwin macbook.local 25.3.0 Darwin Kernel Version 25.3.0: Wed Jan 28 20:51:28 PST 2026; root:xnu-12377.91.3~2/RELEASE_ARM64_T6041 arm64
$ nats --version
0.3.1
$ nats audit analyze file.zip

[ploubser]

Should be fixed by nats-io/jsm.go#792