[RFC v5 126/126] util/qemu-config.c: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy]

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 <address@hidden>
Reported-by: Greg Kurz <address@hidden>
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 util/qemu-config.c | 29 ++++++++++++-----------------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/util/qemu-config.c b/util/qemu-config.c
index 772f5a219e..13e2f797ba 100644
--- a/util/qemu-config.c
+++ b/util/qemu-config.c
@@ -478,10 +478,10 @@ int qemu_read_config_file(const char *filename)
 static void config_parse_qdict_section(QDict *options, QemuOptsList *opts,
                                        Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     QemuOpts *subopts;
     QDict *subqdict;
     QList *list = NULL;
-    Error *local_err = NULL;
     size_t orig_size, enum_size;
     char *prefix;
 
@@ -493,15 +493,13 @@ static void config_parse_qdict_section(QDict *options, 
QemuOptsList *opts,
         goto out;
     }
 
-    subopts = qemu_opts_create(opts, NULL, 0, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    subopts = qemu_opts_create(opts, NULL, 0, errp);
+    if (*errp) {
         goto out;
     }
 
-    qemu_opts_absorb_qdict(subopts, subqdict, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    qemu_opts_absorb_qdict(subopts, subqdict, errp);
+    if (*errp) {
         goto out;
     }
 
@@ -538,16 +536,14 @@ static void config_parse_qdict_section(QDict *options, 
QemuOptsList *opts,
             }
 
             opt_name = g_strdup_printf("%s.%u", opts->name, i++);
-            subopts = qemu_opts_create(opts, opt_name, 1, &local_err);
+            subopts = qemu_opts_create(opts, opt_name, 1, errp);
             g_free(opt_name);
-            if (local_err) {
-                error_propagate(errp, local_err);
+            if (*errp) {
                 goto out;
             }
 
-            qemu_opts_absorb_qdict(subopts, section, &local_err);
-            if (local_err) {
-                error_propagate(errp, local_err);
+            qemu_opts_absorb_qdict(subopts, section, errp);
+            if (*errp) {
                 qemu_opts_del(subopts);
                 goto out;
             }
@@ -569,13 +565,12 @@ out:
 void qemu_config_parse_qdict(QDict *options, QemuOptsList **lists,
                              Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     int i;
-    Error *local_err = NULL;
 
     for (i = 0; lists[i]; i++) {
-        config_parse_qdict_section(options, lists[i], &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        config_parse_qdict_section(options, lists[i], errp);
+        if (*errp) {
             return;
         }
     }
-- 
2.21.0