qapi: Replace start_optional()/end_optional() by optional()

Semantics of end_optional() differ subtly from the other end_FOO()
callbacks: when start_FOO() succeeds, the matching end_FOO() gets
called regardless of what happens in between.  end_optional() gets
called only when everything in between succeeds as well.  Entirely
undocumented, like all of the visitor API.

The only user of Visitor Callback end_optional() never did anything,
and was removed in commit 9f9ab46.

I'm about to clean up error handling in the generated visitor code,
and end_optional() is in my way.  No users mean no test cases, and
making non-trivial cleanup transformations without test cases doesn't
strike me as a good idea.

Drop end_optional(), and rename start_optional() to optional().  We
can always go back to a pair of callbacks when we have an actual need.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index c6579be..9f22eee 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -61,7 +61,7 @@ if (!err) {
     for argname, argentry, optional, structured in parse_args(members):
         if optional:
             ret += mcgen('''
-visit_start_optional(m, &(*obj)->%(c_prefix)shas_%(c_name)s, "%(name)s", &err);
+visit_optional(m, &(*obj)->%(c_prefix)shas_%(c_name)s, "%(name)s", &err);
 if ((*obj)->%(prefix)shas_%(c_name)s) {
 ''',
                          c_prefix=c_var(field_prefix), prefix=field_prefix,
@@ -82,7 +82,6 @@ visit_type_%(type)s(m, &(*obj)->%(c_prefix)s%(c_name)s, "%(name)s", &err);
             pop_indent()
             ret += mcgen('''
 }
-visit_end_optional(m, &err);
 ''')
 
     pop_indent()