qom: Drop parameter @errp of object_property_add() & friends

The only way object_property_add() can fail is when a property with
the same name already exists.  Since our property names are all
hardcoded, failure is a programming error, and the appropriate way to
handle it is passing &error_abort.

Same for its variants, except for object_property_add_child(), which
additionally fails when the child already has a parent.  Parentage is
also under program control, so this is a programming error, too.

We have a bit over 500 callers.  Almost half of them pass
&error_abort, slightly fewer ignore errors, one test case handles
errors, and the remaining few callers pass them to their own callers.

The previous few commits demonstrated once again that ignoring
programming errors is a bad idea.

Of the few ones that pass on errors, several violate the Error API.
The Error ** argument must be NULL, &error_abort, &error_fatal, or a
pointer to a variable containing NULL.  Passing an argument of the
latter kind twice without clearing it in between is wrong: if the
first call sets an error, it no longer points to NULL for the second
call.  ich9_pm_add_properties(), sparc32_ledma_realize(),
sparc32_dma_realize(), xilinx_axidma_realize(), xilinx_enet_realize()
are wrong that way.

When the one appropriate choice of argument is &error_abort, letting
users pick the argument is a bad idea.

Drop parameter @errp and assert the preconditions instead.

There's one exception to "duplicate property name is a programming
error": the way object_property_add() implements the magic (and
undocumented) "automatic arrayification".  Don't drop @errp there.
Instead, rename object_property_add() to object_property_try_add(),
and add the obvious wrapper object_property_add().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200505152926.18877-15-armbru@redhat.com>
[Two semantic rebase conflicts resolved]

10 files changed, 24 insertions, 36 deletions

diff --git a/backends/cryptodev-vhost-user.c b/backends/cryptodev-vhost-user.c
index 6edada8e9e..8b8cbc4223 100644
--- a/backends/cryptodev-vhost-user.c
+++ b/backends/cryptodev-vhost-user.c
@@ -340,8 +340,7 @@ static void cryptodev_vhost_user_instance_int(Object *obj)
 {
     object_property_add_str(obj, "chardev",
                             cryptodev_vhost_user_get_chardev,
-                            cryptodev_vhost_user_set_chardev,
-                            NULL);
+                            cryptodev_vhost_user_set_chardev);
 }
 
 static void cryptodev_vhost_user_finalize(Object *obj)
diff --git a/backends/cryptodev.c b/backends/cryptodev.c
index 5a9735684e..a3841c4e41 100644
--- a/backends/cryptodev.c
+++ b/backends/cryptodev.c
@@ -213,7 +213,7 @@ static void cryptodev_backend_instance_init(Object *obj)
     object_property_add(obj, "queues", "uint32",
                           cryptodev_backend_get_queues,
                           cryptodev_backend_set_queues,
-                          NULL, NULL, NULL);
+                          NULL, NULL);
     /* Initialize devices' queues property to 1 */
     object_property_set_int(obj, 1, "queues", NULL);
 }
diff --git a/backends/dbus-vmstate.c b/backends/dbus-vmstate.c
index cc594a722e..56361a6272 100644
--- a/backends/dbus-vmstate.c
+++ b/backends/dbus-vmstate.c
@@ -481,11 +481,9 @@ dbus_vmstate_class_init(ObjectClass *oc, void *data)
     vc->get_id = dbus_vmstate_get_id;
 
     object_class_property_add_str(oc, "addr",
-                                  get_dbus_addr, set_dbus_addr,
-                                  &error_abort);
+                                  get_dbus_addr, set_dbus_addr);
     object_class_property_add_str(oc, "id-list",
-                                  get_id_list, set_id_list,
-                                  &error_abort);
+                                  get_id_list, set_id_list);
 }
 
 static const TypeInfo dbus_vmstate_info = {
diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c
index c8c355f5aa..cdabb412e6 100644
--- a/backends/hostmem-file.c
+++ b/backends/hostmem-file.c
@@ -184,18 +184,15 @@ file_backend_class_init(ObjectClass *oc, void *data)
     oc->unparent = file_backend_unparent;
 
     object_class_property_add_bool(oc, "discard-data",
-        file_memory_backend_get_discard_data, file_memory_backend_set_discard_data,
-        &error_abort);
+        file_memory_backend_get_discard_data, file_memory_backend_set_discard_data);
     object_class_property_add_str(oc, "mem-path",
-        get_mem_path, set_mem_path,
-        &error_abort);
+        get_mem_path, set_mem_path);
     object_class_property_add(oc, "align", "int",
         file_memory_backend_get_align,
         file_memory_backend_set_align,
-        NULL, NULL, &error_abort);
+        NULL, NULL);
     object_class_property_add_bool(oc, "pmem",
-        file_memory_backend_get_pmem, file_memory_backend_set_pmem,
-        &error_abort);
+        file_memory_backend_get_pmem, file_memory_backend_set_pmem);
 }
 
 static void file_backend_instance_finalize(Object *o)
diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c
index 5991f31459..1b5e4bfe0d 100644
--- a/backends/hostmem-memfd.c
+++ b/backends/hostmem-memfd.c
@@ -141,21 +141,19 @@ memfd_backend_class_init(ObjectClass *oc, void *data)
     if (qemu_memfd_check(MFD_HUGETLB)) {
         object_class_property_add_bool(oc, "hugetlb",
                                        memfd_backend_get_hugetlb,
-                                       memfd_backend_set_hugetlb,
-                                       &error_abort);
+                                       memfd_backend_set_hugetlb);
         object_class_property_set_description(oc, "hugetlb",
                                               "Use huge pages");
         object_class_property_add(oc, "hugetlbsize", "int",
                                   memfd_backend_get_hugetlbsize,
                                   memfd_backend_set_hugetlbsize,
-                                  NULL, NULL, &error_abort);
+                                  NULL, NULL);
         object_class_property_set_description(oc, "hugetlbsize",
                                               "Huge pages size (ex: 2M, 1G)");
     }
     object_class_property_add_bool(oc, "seal",
                                    memfd_backend_get_seal,
-                                   memfd_backend_set_seal,
-                                   &error_abort);
+                                   memfd_backend_set_seal);
     object_class_property_set_description(oc, "seal",
                                           "Seal growing & shrinking");
 }
diff --git a/backends/hostmem.c b/backends/hostmem.c
index 946d176435..4ee4354898 100644
--- a/backends/hostmem.c
+++ b/backends/hostmem.c
@@ -463,51 +463,50 @@ host_memory_backend_class_init(ObjectClass *oc, void *data)
 
     object_class_property_add_bool(oc, "merge",
         host_memory_backend_get_merge,
-        host_memory_backend_set_merge, &error_abort);
+        host_memory_backend_set_merge);
     object_class_property_set_description(oc, "merge",
         "Mark memory as mergeable");
     object_class_property_add_bool(oc, "dump",
         host_memory_backend_get_dump,
-        host_memory_backend_set_dump, &error_abort);
+        host_memory_backend_set_dump);
     object_class_property_set_description(oc, "dump",
         "Set to 'off' to exclude from core dump");
     object_class_property_add_bool(oc, "prealloc",
         host_memory_backend_get_prealloc,
-        host_memory_backend_set_prealloc, &error_abort);
+        host_memory_backend_set_prealloc);
     object_class_property_set_description(oc, "prealloc",
         "Preallocate memory");
     object_class_property_add(oc, "prealloc-threads", "int",
         host_memory_backend_get_prealloc_threads,
         host_memory_backend_set_prealloc_threads,
-        NULL, NULL, &error_abort);
+        NULL, NULL);
     object_class_property_set_description(oc, "prealloc-threads",
         "Number of CPU threads to use for prealloc");
     object_class_property_add(oc, "size", "int",
         host_memory_backend_get_size,
         host_memory_backend_set_size,
-        NULL, NULL, &error_abort);
+        NULL, NULL);
     object_class_property_set_description(oc, "size",
         "Size of the memory region (ex: 500M)");
     object_class_property_add(oc, "host-nodes", "int",
         host_memory_backend_get_host_nodes,
         host_memory_backend_set_host_nodes,
-        NULL, NULL, &error_abort);
+        NULL, NULL);
     object_class_property_set_description(oc, "host-nodes",
         "Binds memory to the list of NUMA host nodes");
     object_class_property_add_enum(oc, "policy", "HostMemPolicy",
         &HostMemPolicy_lookup,
         host_memory_backend_get_policy,
-        host_memory_backend_set_policy, &error_abort);
+        host_memory_backend_set_policy);
     object_class_property_set_description(oc, "policy",
         "Set the NUMA policy");
     object_class_property_add_bool(oc, "share",
-        host_memory_backend_get_share, host_memory_backend_set_share,
-        &error_abort);
+        host_memory_backend_get_share, host_memory_backend_set_share);
     object_class_property_set_description(oc, "share",
         "Mark the memory as private to QEMU or shared");
     object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-id",
         host_memory_backend_get_use_canonical_path,
-        host_memory_backend_set_use_canonical_path, &error_abort);
+        host_memory_backend_set_use_canonical_path);
 }
 
 static const TypeInfo host_memory_backend_info = {
diff --git a/backends/rng-egd.c b/backends/rng-egd.c
index e380519408..7aaa6ee239 100644
--- a/backends/rng-egd.c
+++ b/backends/rng-egd.c
@@ -138,8 +138,7 @@ static char *rng_egd_get_chardev(Object *obj, Error **errp)
 static void rng_egd_init(Object *obj)
 {
     object_property_add_str(obj, "chardev",
-                            rng_egd_get_chardev, rng_egd_set_chardev,
-                            NULL);
+                            rng_egd_get_chardev, rng_egd_set_chardev);
 }
 
 static void rng_egd_finalize(Object *obj)
diff --git a/backends/rng-random.c b/backends/rng-random.c
index a810581393..32998d8ee7 100644
--- a/backends/rng-random.c
+++ b/backends/rng-random.c
@@ -110,8 +110,7 @@ static void rng_random_init(Object *obj)
 
     object_property_add_str(obj, "filename",
                             rng_random_get_filename,
-                            rng_random_set_filename,
-                            NULL);
+                            rng_random_set_filename);
 
     s->filename = g_strdup("/dev/urandom");
     s->fd = -1;
diff --git a/backends/rng.c b/backends/rng.c
index 391888b8b3..597f0ec268 100644
--- a/backends/rng.c
+++ b/backends/rng.c
@@ -108,8 +108,7 @@ static void rng_backend_init(Object *obj)
 
     object_property_add_bool(obj, "opened",
                              rng_backend_prop_get_opened,
-                             rng_backend_prop_set_opened,
-                             NULL);
+                             rng_backend_prop_set_opened);
 }
 
 static void rng_backend_finalize(Object *obj)
diff --git a/backends/vhost-user.c b/backends/vhost-user.c
index 2bf3406525..9e6e198546 100644
--- a/backends/vhost-user.c
+++ b/backends/vhost-user.c
@@ -177,7 +177,7 @@ static char *get_chardev(Object *obj, Error **errp)
 
 static void vhost_user_backend_init(Object *obj)
 {
-    object_property_add_str(obj, "chardev", get_chardev, set_chardev, NULL);
+    object_property_add_str(obj, "chardev", get_chardev, set_chardev);
 }
 
 static void vhost_user_backend_finalize(Object *obj)