qom: Drop object_property_set_description() parameter @errp

object_property_set_description() and
object_class_property_set_description() fail only when property @name
is not found.

There are 85 calls of object_property_set_description() and
object_class_property_set_description().  None of them can fail:

* 84 immediately follow the creation of the property.

* The one in spapr_rng_instance_init() refers to a property created in
  spapr_rng_class_init(), from spapr_rng_properties[].

Every one of them still gets to decide what to pass for @errp.

51 calls pass &error_abort, 32 calls pass NULL, one receives the error
and propagates it to &error_abort, and one propagates it to
&error_fatal.  I'm actually surprised none of them violates the Error
API.

What are we gaining by letting callers handle the "property not found"
error?  Use when the property is not known to exist is simpler: you
don't have to guard the call with a check.  We haven't found such a
use in 5+ years.  Until we do, let's make life a bit simpler and drop
the @errp parameter.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-8-armbru@redhat.com>
[One semantic rebase conflict resolved]

5 files changed, 8 insertions, 9 deletions

diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index f5c49ee32d..18a0af88e2 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -770,8 +770,7 @@ static void aarch64_cpu_initfn(Object *obj)
                              aarch64_cpu_set_aarch64, NULL);
     object_property_set_description(obj, "aarch64",
                                     "Set on/off to enable/disable aarch64 "
-                                    "execution state ",
-                                    NULL);
+                                    "execution state ");
 }
 
 static void aarch64_cpu_finalizefn(Object *obj)
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 390077c518..1ea2d047e3 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -204,7 +204,7 @@ void kvm_arm_add_vcpu_properties(Object *obj)
     object_property_set_description(obj, "kvm-no-adjvtime",
                                     "Set on to disable the adjustment of "
                                     "the virtual counter. VM stopped time "
-                                    "will be counted.", &error_abort);
+                                    "will be counted.");
 }
 
 bool kvm_arm_pmu_supported(CPUState *cpu)
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 846018a12d..6842cfc26d 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -251,19 +251,19 @@ qsev_guest_class_init(ObjectClass *oc, void *data)
                                   qsev_guest_set_sev_device,
                                   NULL);
     object_class_property_set_description(oc, "sev-device",
-            "SEV device to use", NULL);
+            "SEV device to use");
     object_class_property_add_str(oc, "dh-cert-file",
                                   qsev_guest_get_dh_cert_file,
                                   qsev_guest_set_dh_cert_file,
                                   NULL);
     object_class_property_set_description(oc, "dh-cert-file",
-            "guest owners DH certificate (encoded with base64)", NULL);
+            "guest owners DH certificate (encoded with base64)");
     object_class_property_add_str(oc, "session-file",
                                   qsev_guest_get_session_file,
                                   qsev_guest_set_session_file,
                                   NULL);
     object_class_property_set_description(oc, "session-file",
-            "guest owners session parameters (encoded with base64)", NULL);
+            "guest owners session parameters (encoded with base64)");
 }
 
 static void
diff --git a/target/ppc/compat.c b/target/ppc/compat.c
index f48df25944..46ffb6da6d 100644
--- a/target/ppc/compat.c
+++ b/target/ppc/compat.c
@@ -324,7 +324,7 @@ void ppc_compat_add_property(Object *obj, const char *name,
 
     names = g_strjoinv(", ", namesv);
     desc = g_strdup_printf("%s. Valid values are %s.", basedesc, names);
-    object_property_set_description(obj, name, desc, &local_err);
+    object_property_set_description(obj, name, desc);
 
     g_free(names);
     g_free(desc);
diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 7c32180269..aa7fc713ca 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -1107,13 +1107,13 @@ void s390_cpu_model_register_props(Object *obj)
         const S390FeatDef *def = s390_feat_def(feat);
         object_property_add(obj, def->name, "bool", get_feature,
                             set_feature, NULL, (void *) feat, NULL);
-        object_property_set_description(obj, def->name, def->desc , NULL);
+        object_property_set_description(obj, def->name, def->desc);
     }
     for (group = 0; group < S390_FEAT_GROUP_MAX; group++) {
         const S390FeatGroupDef *def = s390_feat_group_def(group);
         object_property_add(obj, def->name, "bool", get_feature_group,
                             set_feature_group, NULL, (void *) group, NULL);
-        object_property_set_description(obj, def->name, def->desc , NULL);
+        object_property_set_description(obj, def->name, def->desc);
     }
 }