qapi: New -compat deprecated-input=crash

Policy "crash" calls abort() when deprecated input is received.

Bugs in integration tests may mask the error from policy "reject".
Provide a larger hammer: crash outright.  Masking that seems unlikely.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210318155519.1224118-12-armbru@redhat.com>

qapi/compat.json

@@ -11,11 +11,12 @@
 #
 # @accept: Accept silently
 # @reject: Reject with an error
+# @crash: abort() the process
 #
 # Since: 6.0
 ##
 { 'enum': 'CompatPolicyInput',
-  'data': [ 'accept', 'reject' ] }
+  'data': [ 'accept', 'reject', 'crash' ] }
 
 ##
 # @CompatPolicyOutput:

qapi/qmp-dispatch.c

@@ -185,6 +185,7 @@ QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request,
                       "Deprecated command %s disabled by policy",
                       command);
             goto out;
+        case COMPAT_POLICY_INPUT_CRASH:
         default:
             abort();
         }

qapi/qobject-input-visitor.c

@@ -676,6 +676,7 @@ static bool qobject_input_deprecated_accept(Visitor *v, const char *name,
         error_setg(errp, "Deprecated parameter '%s' disabled by policy",
                    name);
         return false;
+    case COMPAT_POLICY_INPUT_CRASH:
     default:
         abort();
     }

qemu-options.hx

@@ -3508,7 +3508,7 @@ DEFHEADING()
 DEFHEADING(Debug/Expert options:)
 
 DEF("compat", HAS_ARG, QEMU_OPTION_compat,
-    "-compat [deprecated-input=accept|reject][,deprecated-output=accept|hide]\n"
+    "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n"
     "                Policy for handling deprecated management interfaces\n",
     QEMU_ARCH_ALL)
 SRST
@@ -3519,6 +3519,8 @@ SRST
         Accept deprecated commands and arguments
     ``deprecated-input=reject``
         Reject deprecated commands and arguments
+    ``deprecated-input=crash``
+        Crash on deprecated commands and arguments
     ``deprecated-output=accept`` (default)
         Emit deprecated command results and events
     ``deprecated-output=hide``