[PATCH v2 07/15] qapi: Fix Visitor contract for start_alternate()

[Markus Armbruster <armbru@redhat.com>]

The contract demands v->start_alternate() for input and dealloc
visitors, but visit_start_alternate() actually requires it for input
and clone visitors.  Fix the contract, and delete superfluous
qapi_dealloc_start_alternate().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 include/qapi/visitor-impl.h | 5 ++---
 qapi/qapi-dealloc-visitor.c | 7 -------
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 8ccb3b6c20..252206dc0d 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -67,13 +67,12 @@ struct Visitor
     /* Must be set */
     void (*end_list)(Visitor *v, void **list);
 
-    /* Must be set by input and dealloc visitors to visit alternates;
-     * optional for output visitors. */
+    /* Must be set by input and clone visitors to visit alternates */
     void (*start_alternate)(Visitor *v, const char *name,
                             GenericAlternate **obj, size_t size,
                             Error **errp);
 
-    /* Optional, needed for dealloc visitor */
+    /* Optional */
     void (*end_alternate)(Visitor *v, void **obj);
 
     /* Must be set */
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index d192724b13..2239fc6417 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -34,12 +34,6 @@ static void qapi_dealloc_end_struct(Visitor *v, void **obj)
     }
 }
 
-static void qapi_dealloc_start_alternate(Visitor *v, const char *name,
-                                         GenericAlternate **obj, size_t size,
-                                         Error **errp)
-{
-}
-
 static void qapi_dealloc_end_alternate(Visitor *v, void **obj)
 {
     if (obj) {
@@ -123,7 +117,6 @@ Visitor *qapi_dealloc_visitor_new(void)
     v->visitor.type = VISITOR_DEALLOC;
     v->visitor.start_struct = qapi_dealloc_start_struct;
     v->visitor.end_struct = qapi_dealloc_end_struct;
-    v->visitor.start_alternate = qapi_dealloc_start_alternate;
     v->visitor.end_alternate = qapi_dealloc_end_alternate;
     v->visitor.start_list = qapi_dealloc_start_list;
     v->visitor.next_list = qapi_dealloc_next_list;
-- 
2.21.1