[a-palamarchuk]

Problem

In Server.Start, the pprof goroutine logged an error only when Serve returned http.ErrServerClosed:

if err := p.pprofServer.Serve(ln); err != nil && errors.Is(err, http.ErrServerClosed) {
	p.logger.Error("pprof server error", "error", err)
}

http.ErrServerClosed is the expected result of Stop(). So every clean exit with --pprof logs an error, and real serve failures are dropped silently.

Change

• Invert the check to !errors.Is(err, http.ErrServerClosed).
• Move the goroutine body into servePprof(ln) so a test can call it synchronously.
• Add TestServePprofLogsOnlyUnexpectedErrors, which covers both a clean shutdown and a real serve failure on a closed listener. Both subtests fail on main and pass with this change.

Testing

Before (main) and after (this branch), using boundary --jail-type=landjail --pprof --pprof-port 6061 --disable-audit-logs --log-level info -- sh -c 'sleep 0.3':

# main: every run
level=INFO msg="Serving pprof on existing listener" port=6061
level=ERROR msg="pprof server error" error="http: Server closed"

# this branch: every run
level=INFO msg="Serving pprof on existing listener" port=6061

• make unit-test: pass. On main without test(proxy): serve proxy test upstreams locally #213, TestProxyServerImplicitCONNECT and TestMultipleRequestsOverExplicitCONNECT fail because dev.coder.com now redirects; that PR fixes them.
• make fmt-check: passes.

AI disclosure

I used Claude Code to find the bug and draft the fix. I reviewed the diff and ran the checks above myself.