vl: Deprecate -mon pretty=... for HMP monitors

The -mon pretty=on|off switch of the -mon option applies only to QMP
monitors. It's silently ignored for HMP. Deprecate this combination so
that we can make it an error in future versions.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20190613153405.24769-16-kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

qemu-deprecated.texi

@@ -72,6 +72,12 @@ backend settings instead of environment variables.  To ease migration to
 the new format, the ``-audiodev-help'' option can be used to convert
 the current values of the environment variables to ``-audiodev'' options.
 
+@subsection -mon ...,control=readline,pretty=on|off (since 4.1)
+
+The @code{pretty=on|off} switch has no effect for HMP monitors, but is
+silently ignored. Using the switch with HMP monitors will become an
+error in the future.
+
 @subsection -realtime (since 4.1)
 
 The @code{-realtime mlock=on|off} argument has been replaced by the

vl.c

@@ -2317,6 +2317,10 @@ static int mon_init_func(void *opaque, QemuOpts *opts, Error **errp)
         return -1;
     }
 
+    if (!qmp && qemu_opt_get(opts, "pretty")) {
+        warn_report("'pretty' is deprecated for HMP monitors, it has no effect "
+                    "and will be removed in future versions");
+    }
     if (qemu_opt_get_bool(opts, "pretty", 0)) {
         pretty = true;
     }
@@ -2362,7 +2366,11 @@ static void monitor_parse(const char *optarg, const char *mode, bool pretty)
     opts = qemu_opts_create(qemu_find_opts("mon"), label, 1, &error_fatal);
     qemu_opt_set(opts, "mode", mode, &error_abort);
     qemu_opt_set(opts, "chardev", label, &error_abort);
-    qemu_opt_set_bool(opts, "pretty", pretty, &error_abort);
+    if (!strcmp(mode, "control")) {
+        qemu_opt_set_bool(opts, "pretty", pretty, &error_abort);
+    } else {
+        assert(pretty == false);
+    }
     monitor_device_index++;
 }