qapi: Fix alternates that accept 'number' but not 'int'

The QMP input visitor allows integral values to be assigned by
promotion to a QTYPE_QFLOAT.  However, when parsing an alternate,
we did not take this into account, such that an alternate that
accepts 'number' and some other type, but not 'int', would reject
integral values.

With this patch, we now have the following desirable table:

    alternate has      case selected for
    'int'  'number'    QTYPE_QINT  QTYPE_QFLOAT
      no        no     error       error
      no       yes     'number'    'number'
     yes        no     'int'       error
     yes       yes     'int'       'number'

While it is unlikely that we will ever use 'number' in an
alternate other than in the testsuite, it never hurts to be
more precise in what we allow.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1449033659-25497-8-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

include/qapi/visitor-impl.h

@@ -33,7 +33,7 @@ struct Visitor
     void (*type_enum)(Visitor *v, int *obj, const char * const strings[],
                       const char *kind, const char *name, Error **errp);
     /* May be NULL; only needed for input visitors. */
-    void (*get_next_type)(Visitor *v, QType *type,
+    void (*get_next_type)(Visitor *v, QType *type, bool promote_int,
                           const char *name, Error **errp);
 
     void (*type_int)(Visitor *v, int64_t *obj, const char *name, Error **errp);

include/qapi/visitor.h

@@ -43,8 +43,9 @@ void visit_optional(Visitor *v, bool *present, const char *name,
  * Determine the qtype of the item @name in the current object visit.
  * For input visitors, set *@type to the correct qtype of a qapi
  * alternate type; for other visitors, leave *@type unchanged.
+ * If @promote_int, treat integers as QTYPE_FLOAT.
  */
-void visit_get_next_type(Visitor *v, QType *type,
+void visit_get_next_type(Visitor *v, QType *type, bool promote_int,
                          const char *name, Error **errp);
 void visit_type_enum(Visitor *v, int *obj, const char * const strings[],
                      const char *kind, const char *name, Error **errp);

qapi/qapi-visit-core.c

@@ -81,11 +81,11 @@ void visit_optional(Visitor *v, bool *present, const char *name,
     }
 }
 
-void visit_get_next_type(Visitor *v, QType *type,
+void visit_get_next_type(Visitor *v, QType *type, bool promote_int,
                          const char *name, Error **errp)
 {
     if (v->get_next_type) {
-        v->get_next_type(v, type, name, errp);
+        v->get_next_type(v, type, promote_int, name, errp);
     }
 }
 

qapi/qmp-input-visitor.c

@@ -208,7 +208,7 @@ static void qmp_input_end_list(Visitor *v, Error **errp)
     qmp_input_pop(qiv, errp);
 }
 
-static void qmp_input_get_next_type(Visitor *v, QType *type,
+static void qmp_input_get_next_type(Visitor *v, QType *type, bool promote_int,
                                     const char *name, Error **errp)
 {
     QmpInputVisitor *qiv = to_qiv(v);
@@ -219,6 +219,9 @@ static void qmp_input_get_next_type(Visitor *v, QType *type,
         return;
     }
     *type = qobject_type(qobj);
+    if (promote_int && *type == QTYPE_QINT) {
+        *type = QTYPE_QFLOAT;
+    }
 }
 
 static void qmp_input_type_int(Visitor *v, int64_t *obj, const char *name,

scripts/qapi-visit.py

@@ -184,6 +184,11 @@ def gen_visit_enum(name):
 
 
 def gen_visit_alternate(name, variants):
+    promote_int = 'true'
+    for var in variants.variants:
+        if var.type.alternate_qtype() == 'QTYPE_QINT':
+            promote_int = 'false'
+
     ret = mcgen('''
 
 void visit_type_%(c_name)s(Visitor *v, %(c_name)s **obj, const char *name, Error **errp)
@@ -194,16 +199,14 @@ def gen_visit_alternate(name, variants):
     if (err) {
         goto out;
     }
-    visit_get_next_type(v, &(*obj)->type, name, &err);
+    visit_get_next_type(v, &(*obj)->type, %(promote_int)s, name, &err);
     if (err) {
         goto out_obj;
     }
     switch ((*obj)->type) {
 ''',
-                c_name=c_name(name))
+                c_name=c_name(name), promote_int=promote_int)
 
-    # FIXME: When 'number' but not 'int' is present in the alternate, we
-    # should allow QTYPE_INT to promote to QTYPE_FLOAT.
     for var in variants.variants:
         ret += mcgen('''
     case %(case)s:

tests/test-qmp-input-visitor.c

@@ -347,20 +347,16 @@ static void test_visitor_in_alternate_number(TestInputVisitorData *data,
     error_free_or_abort(&err);
     qapi_free_AltStrBool(asb);
 
-    /* FIXME: integer should parse as number */
     v = visitor_input_test_init(data, "42");
-    visit_type_AltStrNum(v, &asn, NULL, &err);
-    /* FIXME g_assert_cmpint(asn->type, ==, QTYPE_QFLOAT); */
-    /* FIXME g_assert_cmpfloat(asn->u.n, ==, 42); */
-    error_free_or_abort(&err);
+    visit_type_AltStrNum(v, &asn, NULL, &error_abort);
+    g_assert_cmpint(asn->type, ==, QTYPE_QFLOAT);
+    g_assert_cmpfloat(asn->u.n, ==, 42);
     qapi_free_AltStrNum(asn);
 
-    /* FIXME: integer should parse as number */
     v = visitor_input_test_init(data, "42");
-    visit_type_AltNumStr(v, &ans, NULL, &err);
-    /* FIXME g_assert_cmpint(ans->type, ==, QTYPE_QFLOAT); */
-    /* FIXME g_assert_cmpfloat(ans->u.n, ==, 42); */
-    error_free_or_abort(&err);
+    visit_type_AltNumStr(v, &ans, NULL, &error_abort);
+    g_assert_cmpint(ans->type, ==, QTYPE_QFLOAT);
+    g_assert_cmpfloat(ans->u.n, ==, 42);
     qapi_free_AltNumStr(ans);
 
     v = visitor_input_test_init(data, "42");