If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 monitor/misc.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/monitor/misc.c b/monitor/misc.c
index aef16f6cfb..4c658884f4 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -1775,20 +1775,19 @@ void monitor_fdset_dup_fd_remove(int dup_fd)
 
 int monitor_fd_param(Monitor *mon, const char *fdname, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int fd;
-    Error *local_err = NULL;
 
     if (!qemu_isdigit(fdname[0]) && mon) {
-        fd = monitor_get_fd(mon, fdname, &local_err);
+        fd = monitor_get_fd(mon, fdname, errp);
     } else {
         fd = qemu_parse_fd(fdname);
         if (fd == -1) {
-            error_setg(&local_err, "Invalid file descriptor number '%s'",
+            error_setg(errp, "Invalid file descriptor number '%s'",
                        fdname);
         }
     }
-    if (local_err) {
-        error_propagate(errp, local_err);
+    if (*errp) {
         assert(fd == -1);
     } else {
         assert(fd != -1);
-- 
2.21.0