error: Eliminate error_propagate() with Coccinelle, part 2

When all we do with an Error we receive into a local variable is
propagating to somewhere else, we can just as well receive it there
right away.  The previous commit did that with a Coccinelle script I
consider fairly trustworthy.  This commit uses the same script with
the matching of return taken out, i.e. we convert

    if (!foo(..., &err)) {
        ...
        error_propagate(errp, err);
        ...
    }

to

    if (!foo(..., errp)) {
        ...
        ...
    }

This is unsound: @err could still be read between afterwards.  I don't
know how to express "no read of @err without an intervening write" in
Coccinelle.  Instead, I manually double-checked for uses of @err.

Suboptimal line breaks tweaked manually.  qdev_realize() simplified
further to placate scripts/checkpatch.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200707160613.848843-36-armbru@redhat.com>

1 files changed, 1 insertions, 3 deletions

diff --git a/qom/object.c b/qom/object.c
index 08b2cad445..37e4bc45b1 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1599,11 +1599,9 @@ char *object_property_print(Object *obj, const char *name, bool human,
 {
     Visitor *v;
     char *string = NULL;
-    Error *local_err = NULL;
 
     v = string_output_visitor_new(human, &string);
-    if (!object_property_get(obj, name, v, &local_err)) {
-        error_propagate(errp, local_err);
+    if (!object_property_get(obj, name, v, errp)) {
         goto out;
     }