Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2020-07-07-v2' into staging

Error reporting patches patches for 2020-07-07

# gpg: Signature made Fri 10 Jul 2020 14:24:42 BST
# gpg:                using RSA key 354BC8B3D7EB2A6B68674E5F3870B400EB918653
# gpg:                issuer "armbru@redhat.com"
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>" [full]
# gpg:                 aka "Markus Armbruster <armbru@pond.sub.org>" [full]
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867  4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-error-2020-07-07-v2: (53 commits)
  xen: Use ERRP_GUARD()
  nbd: Use ERRP_GUARD()
  virtio-9p: Use ERRP_GUARD()
  fw_cfg: Use ERRP_GUARD()
  pflash: Use ERRP_GUARD()
  sd: Use ERRP_GUARD()
  scripts: Coccinelle script to use ERRP_GUARD()
  error: New macro ERRP_GUARD()
  hmp: Ignore Error objects where the return value suffices
  qdev: Ignore Error objects where the return value suffices
  qemu-img: Ignore Error objects where the return value suffices
  error: Avoid error_propagate() after migrate_add_blocker()
  qapi: Purge error_propagate() from QAPI core
  qapi: Smooth visitor error checking in generated code
  qapi: Smooth another visitor error checking pattern
  block/parallels: Simplify parallels_open() after previous commit
  error: Reduce unnecessary error propagation
  error: Eliminate error_propagate() manually
  error: Eliminate error_propagate() with Coccinelle, part 2
  error: Eliminate error_propagate() with Coccinelle, part 1
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 43 insertions, 64 deletions

diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index d5d7a1031f..3fb2f30510 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -23,7 +23,7 @@ def gen_visit_decl(name, scalar=False):
     if not scalar:
         c_type += '*'
     return mcgen('''
-void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
+bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
 ''',
                  c_name=c_name(name), c_type=c_type)
 
@@ -31,7 +31,7 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **
 def gen_visit_members_decl(name):
     return mcgen('''
 
-void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
+bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
 ''',
                  c_name=c_name(name))
 
@@ -39,18 +39,15 @@ void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
 def gen_visit_object_members(name, base, members, variants):
     ret = mcgen('''
 
-void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
+bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
 {
-    Error *err = NULL;
-
 ''',
                 c_name=c_name(name))
 
     if base:
         ret += mcgen('''
-    visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, &err);
-    if (err) {
-        goto out;
+    if (!visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, errp)) {
+        return false;
     }
 ''',
                      c_type=base.c_name())
@@ -64,9 +61,8 @@ void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
                          name=memb.name, c_name=c_name(memb.name))
             push_indent()
         ret += mcgen('''
-    visit_type_%(c_type)s(v, "%(name)s", &obj->%(c_name)s, &err);
-    if (err) {
-        goto out;
+    if (!visit_type_%(c_type)s(v, "%(name)s", &obj->%(c_name)s, errp)) {
+        return false;
     }
 ''',
                      c_type=memb.type.c_name(), name=memb.name,
@@ -99,8 +95,7 @@ void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
             else:
                 ret += mcgen('''
     case %(case)s:
-        visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, &err);
-        break;
+        return visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, errp);
 ''',
                              case=case_str,
                              c_type=var.type.c_name(), c_name=c_name(var.name))
@@ -112,15 +107,8 @@ void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
     }
 ''')
 
-    # 'goto out' produced for base, for each member, and if variants were
-    # present
-    if base or members or variants:
-        ret += mcgen('''
-
-out:
-''')
     ret += mcgen('''
-    error_propagate(errp, err);
+    return true;
 }
 ''')
     return ret
@@ -129,35 +117,31 @@ out:
 def gen_visit_list(name, element_type):
     return mcgen('''
 
-void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
 {
-    Error *err = NULL;
+    bool ok = false;
     %(c_name)s *tail;
     size_t size = sizeof(**obj);
 
-    visit_start_list(v, name, (GenericList **)obj, size, &err);
-    if (err) {
-        goto out;
+    if (!visit_start_list(v, name, (GenericList **)obj, size, errp)) {
+        return false;
     }
 
     for (tail = *obj; tail;
          tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) {
-        visit_type_%(c_elt_type)s(v, NULL, &tail->value, &err);
-        if (err) {
-            break;
+        if (!visit_type_%(c_elt_type)s(v, NULL, &tail->value, errp)) {
+            goto out_obj;
         }
     }
 
-    if (!err) {
-        visit_check_list(v, &err);
-    }
+    ok = visit_check_list(v, errp);
+out_obj:
     visit_end_list(v, (void **)obj);
-    if (err && visit_is_input(v)) {
+    if (!ok && visit_is_input(v)) {
         qapi_free_%(c_name)s(*obj);
         *obj = NULL;
     }
-out:
-    error_propagate(errp, err);
+    return ok;
 }
 ''',
                  c_name=c_name(name), c_elt_type=element_type.c_name())
@@ -166,11 +150,12 @@ out:
 def gen_visit_enum(name):
     return mcgen('''
 
-void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
+bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
 {
     int value = *obj;
-    visit_type_enum(v, name, &value, &%(c_name)s_lookup, errp);
+    bool ok = visit_type_enum(v, name, &value, &%(c_name)s_lookup, errp);
     *obj = value;
+    return ok;
 }
 ''',
                  c_name=c_name(name))
@@ -179,18 +164,18 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error
 def gen_visit_alternate(name, variants):
     ret = mcgen('''
 
-void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
 {
-    Error *err = NULL;
+    bool ok = false;
 
-    visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
-                          &err);
-    if (err) {
-        goto out;
+    if (!visit_start_alternate(v, name, (GenericAlternate **)obj,
+                               sizeof(**obj), errp)) {
+        return false;
     }
     if (!*obj) {
         /* incomplete */
         assert(visit_is_dealloc(v));
+        ok = true;
         goto out_obj;
     }
     switch ((*obj)->type) {
@@ -205,13 +190,11 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
                      case=var.type.alternate_qtype())
         if isinstance(var.type, QAPISchemaObjectType):
             ret += mcgen('''
-        visit_start_struct(v, name, NULL, 0, &err);
-        if (err) {
+        if (!visit_start_struct(v, name, NULL, 0, errp)) {
             break;
         }
-        visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);
-        if (!err) {
-            visit_check_struct(v, &err);
+        if (visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, errp)) {
+            ok = visit_check_struct(v, errp);
         }
         visit_end_struct(v, NULL);
 ''',
@@ -219,7 +202,7 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
                          c_name=c_name(var.name))
         else:
             ret += mcgen('''
-        visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);
+        ok = visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, errp);
 ''',
                          c_type=var.type.c_name(),
                          c_name=c_name(var.name))
@@ -233,7 +216,7 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
         abort();
     default:
         assert(visit_is_input(v));
-        error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+        error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
                    "%(name)s");
         /* Avoid passing invalid *obj to qapi_free_%(c_name)s() */
         g_free(*obj);
@@ -241,12 +224,11 @@ void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error
     }
 out_obj:
     visit_end_alternate(v, (void **)obj);
-    if (err && visit_is_input(v)) {
+    if (!ok && visit_is_input(v)) {
         qapi_free_%(c_name)s(*obj);
         *obj = NULL;
     }
-out:
-    error_propagate(errp, err);
+    return ok;
 }
 ''',
                  name=name, c_name=c_name(name))
@@ -257,32 +239,29 @@ out:
 def gen_visit_object(name, base, members, variants):
     return mcgen('''
 
-void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+bool visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
 {
-    Error *err = NULL;
+    bool ok = false;
 
-    visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
-    if (err) {
-        goto out;
+    if (!visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), errp)) {
+        return false;
     }
     if (!*obj) {
         /* incomplete */
         assert(visit_is_dealloc(v));
         goto out_obj;
     }
-    visit_type_%(c_name)s_members(v, *obj, &err);
-    if (err) {
+    if (!visit_type_%(c_name)s_members(v, *obj, errp)) {
         goto out_obj;
     }
-    visit_check_struct(v, &err);
+    ok = visit_check_struct(v, errp);
 out_obj:
     visit_end_struct(v, (void **)obj);
-    if (err && visit_is_input(v)) {
+    if (!ok && visit_is_input(v)) {
         qapi_free_%(c_name)s(*obj);
         *obj = NULL;
     }
-out:
-    error_propagate(errp, err);
+    return ok;
 }
 ''',
                  c_name=c_name(name))