fix(output): suppress the pulumi-command AcceptEnv warning noise

internal/output/stream.go

@@ -140,7 +140,7 @@ func (p *Printer) Handle(ev events.EngineEvent) {
 		switch d.Severity {
 		case "error", "warning", "info#err":
 			msg := strings.TrimSpace(d.Message)
-			if msg == "" {
+			if msg == "" || isKnownNoise(msg) {
 				return
 			}
 			if d.Severity == "error" && d.URN != "" {
@@ -276,6 +276,19 @@ func (p *Printer) Finish() {
 	_, _ = fmt.Fprintln(p.w, abortBanner)
 }
 
+// isKnownNoise drops diagnostics that carry no operator-actionable signal and
+// repeat on EVERY remote command of EVERY deploy. Currently exactly one: the
+// pulumi-command remote provider tries to pass PULUMI_COMMAND_STDOUT/STDERR as
+// SSH env vars, OpenSSH's default AcceptEnv rejects them, and the provider
+// warns — harmless (the vars only control the provider's own log forwarding;
+// command stdout/stderr capture is unaffected) and unfixable from here short
+// of loosening every host's sshd AcceptEnv for a cosmetic win. Keep this list
+// SHORT and exact-prefix-matched: a suppression that grows becomes a place
+// real warnings go to die.
+func isKnownNoise(msg string) bool {
+	return strings.HasPrefix(msg, "Unable to set 'PULUMI_COMMAND_")
+}
+
 func firstLine(s string) string {
 	if i := strings.IndexByte(s, '\n'); i >= 0 {
 		return strings.TrimSpace(s[:i])

internal/output/translate_test.go

@@ -148,3 +148,27 @@ func TestPrinterDestructiveAccessor(t *testing.T) {
 		t.Errorf("entry = %q", p.Destructive()[0])
 	}
 }
+
+// The pulumi-command remote provider warns about PULUMI_COMMAND_* SSH env vars
+// on EVERY command of EVERY deploy — non-actionable noise that buried the real
+// lines. It is suppressed; a real warning still prints.
+func TestKnownNoiseWarningsAreSuppressed(t *testing.T) {
+	var buf bytes.Buffer
+	p := NewPrinter(&buf)
+	diag := func(sev, msg string) events.EngineEvent {
+		return events.EngineEvent{EngineEvent: apitype.EngineEvent{
+			DiagnosticEvent: &apitype.DiagnosticEvent{Severity: sev, Message: msg},
+		}}
+	}
+	p.Handle(diag("warning", "Unable to set 'PULUMI_COMMAND_STDERR'. This only works if your SSH server is configured to accept these variables via AcceptEnv."))
+	p.Handle(diag("warning", "Unable to set 'PULUMI_COMMAND_STDOUT'. This only works if your SSH server is configured to accept these variables via AcceptEnv."))
+	p.Handle(diag("warning", "a REAL warning about something else"))
+	p.Finish()
+	out := buf.String()
+	if strings.Contains(out, "PULUMI_COMMAND_") {
+		t.Errorf("the AcceptEnv provider noise must be suppressed:\n%s", out)
+	}
+	if !strings.Contains(out, "a REAL warning about something else") {
+		t.Errorf("real warnings must still print:\n%s", out)
+	}
+}