fix: ListLocalServers returns error instead of writing to os.Stderr

Author: dlevy-msft-sql

cmd/sqlcmd/sqlcmd.go

@@ -232,7 +232,9 @@ func Execute(version string) {
 					fmt.Println()
 					fmt.Println(localizer.Sprintf("Servers:"))
 				}
-				sqlcmd.ListLocalServers(os.Stdout)
+				if err := sqlcmd.ListLocalServers(os.Stdout); err != nil {
+					fmt.Fprintln(os.Stderr, err)
+				}
 				os.Exit(0)
 			}
 			if len(argss) > 0 {

pkg/sqlcmd/commands.go

@@ -661,7 +661,9 @@ func serverlistCommand(s *Sqlcmd, args []string, line uint) error {
 	if len(args) > 0 && strings.TrimSpace(args[0]) != "" {
 		return InvalidCommandError("SERVERLIST", line)
 	}
-	ListLocalServers(s.GetOutput())
+	if err := ListLocalServers(s.GetOutput()); err != nil {
+		_, _ = fmt.Fprintln(s.GetError(), err)
+	}
 	return nil
 }
 

pkg/sqlcmd/serverlist.go

@@ -19,14 +19,15 @@ import (
 
 // ListLocalServers queries the SQL Browser service for available SQL Server instances
 // and writes the results to the provided writer.
-func ListLocalServers(w io.Writer) {
+func ListLocalServers(w io.Writer) error {
 	instances, err := GetLocalServerInstances()
 	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		return err
 	}
 	for _, s := range instances {
 		_, _ = fmt.Fprintf(w, "  %s\n", s)
 	}
+	return nil
 }
 
 // GetLocalServerInstances queries the SQL Browser service and returns a list of

pkg/sqlcmd/serverlist_test.go

@@ -14,7 +14,10 @@ func TestListLocalServers(t *testing.T) {
 	// Test that ListLocalServers writes to the provided writer without error
 	// Note: actual server discovery depends on SQL Browser service availability
 	var buf bytes.Buffer
-	ListLocalServers(&buf)
+	err := ListLocalServers(&buf)
+	if err != nil {
+		t.Logf("ListLocalServers returned error (expected in some environments): %v", err)
+	}
 	// We can't assert specific content since it depends on environment,
 	// but we verify it doesn't panic and writes valid output
 	t.Logf("ListLocalServers output: %q", buf.String())