qemu-option: do not suggest using the delay option

The "delay" option was a hack that was introduced to allow writing "nodelay".
We are adding a "nodelay" option to be used as "nodelay=on", so recommend it
instead of "delay".

This is quite ugly, but a proper deprecation of "delay"
cannot be done if QEMU starts suggesting it.  Since it's the
only case I opted for this very much ad-hoc patch.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/system/deprecated.rst

@@ -134,6 +134,12 @@ Boolean options such as ``share=on``/``share=off`` could be written
 in short form as ``share`` and ``noshare``.  This is now deprecated
 and will cause a warning.
 
+``delay`` option for socket character devices (since 6.0)
+'''''''''''''''''''''''''''''''''''''''''''''''''''''''''
+
+The replacement for the ``nodelay`` short-form boolean option is ``nodelay=on``
+rather than ``delay=off``.
+
 ``--enable-fips`` (since 6.0)
 '''''''''''''''''''''''''''''
 

util/qemu-option.c

@@ -785,7 +785,11 @@ static const char *get_opt_name_value(const char *params,
             }
             if (!is_help && warn_on_flag) {
                 warn_report("short-form boolean option '%s%s' deprecated", prefix, *name);
-                error_printf("Please use %s=%s instead\n", *name, *value);
+                if (g_str_equal(*name, "delay")) {
+                    error_printf("Please use nodelay=%s instead\n", prefix[0] ? "on" : "off");
+                } else {
+                    error_printf("Please use %s=%s instead\n", *name, *value);
+                }
             }
         }
     } else {