serf: segmentation violation during test (make test)

[hw-claudio]

Hello,

with latest code at commit 0dfa446, Tue Nov 25 11:49:52 2025 +0530

I get the following segmentation violation error during make test:

$ make

--> Running go vet
go test ./...
? github.com/hashicorp/serf/client [no test files]
? github.com/hashicorp/serf/cmd/serf [no test files]
? github.com/hashicorp/serf/serf/internal/race [no test files]
? github.com/hashicorp/serf/version [no test files]
ok github.com/hashicorp/serf/cmd/serf/command 21.919s
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x8079ee]

goroutine 175 [running]:
github.com/hashicorp/serf/cmd/serf/command/agent.(*Command).startAgent(0xc0000d2820, 0xc0000b1188, 0xc0000d02a0, 0xc0000a99e0, {0x9ca080, 0xc000384a20})
/home/claudio/git/serf/cmd/serf/command/agent/command.go:458 +0x30e
github.com/hashicorp/serf/cmd/serf/command/agent.(*Command).Run(0xc0000d2820, {0xc0001a7b00, 0x8, 0x8})
/home/claudio/git/serf/cmd/serf/command/agent/command.go:619 +0x5e6
github.com/hashicorp/serf/cmd/serf/command/agent.TestCommandRun_mDNS.func4()
/home/claudio/git/serf/cmd/serf/command/agent/command_test.go:325 +0x30
created by github.com/hashicorp/serf/cmd/serf/command/agent.TestCommandRun_mDNS in goroutine 173
/home/claudio/git/serf/cmd/serf/command/agent/command_test.go:324 +0x6a9
FAIL github.com/hashicorp/serf/cmd/serf/command/agent 11.053s
ok github.com/hashicorp/serf/coordinate (cached)
ok github.com/hashicorp/serf/serf (cached)
ok github.com/hashicorp/serf/testutil (cached) [no tests to run]
ok github.com/hashicorp/serf/testutil/retry (cached)
FAIL
make: *** [GNUmakefile:43: test] Error 1