[PATCH 12/12] error: Kill @error_warn

[Markus Armbruster <armbru@redhat.com>]

We added @error_warn some two years ago in commit 3ffef1a55ca (error:
add global &error_warn destination).  It has multiple issues:

* error.h's big comment was not updated for it.

* Function contracts were not updated for it.

* ERRP_GUARD() is unaware of @error_warn, and fails to mask it from
  error_prepend() and such.  These crash on @error_warn, as pointed
  out by Akihiko Odaki.

All fixable.  However, after more than two years, we had just of 15
uses, of which the last few patches removed eight as unclean or
otherwise undesirable.  I didn't look closely enough at the remaining
seven to decide whether they are desirable or not.

I don't think this feature earns its keep.  Drop it.

Thanks-to: Akihiko  Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 include/qapi/error.h           |  6 ------
 hw/display/virtio-gpu.c        |  8 ++++++--
 hw/net/virtio-net.c            |  8 +++++++-
 tests/unit/test-error-report.c | 17 -----------------
 ui/gtk.c                       |  6 +++++-
 util/error.c                   |  5 +----
 6 files changed, 19 insertions(+), 31 deletions(-)

diff --git a/include/qapi/error.h b/include/qapi/error.h
index 41e3816380..b16c6303f8 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -533,12 +533,6 @@ static inline void error_propagator_cleanup(ErrorPropagator *prop)
 
 G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(ErrorPropagator, error_propagator_cleanup);
 
-/*
- * Special error destination to warn on error.
- * See error_setg() and error_propagate() for details.
- */
-extern Error *error_warn;
-
 /*
  * Special error destination to abort on error.
  * See error_setg() and error_propagate() for details.
diff --git a/hw/display/virtio-gpu.c b/hw/display/virtio-gpu.c
index 0a1a625b0e..de35902213 100644
--- a/hw/display/virtio-gpu.c
+++ b/hw/display/virtio-gpu.c
@@ -242,6 +242,7 @@ static uint32_t calc_image_hostmem(pixman_format_code_t pformat,
 static void virtio_gpu_resource_create_2d(VirtIOGPU *g,
                                           struct virtio_gpu_ctrl_command *cmd)
 {
+    Error *err = NULL;
     pixman_format_code_t pformat;
     struct virtio_gpu_simple_resource *res;
     struct virtio_gpu_resource_create_2d c2d;
@@ -293,7 +294,8 @@ static void virtio_gpu_resource_create_2d(VirtIOGPU *g,
                 c2d.width,
                 c2d.height,
                 c2d.height ? res->hostmem / c2d.height : 0,
-                &error_warn)) {
+                &err)) {
+            warn_report_err(err);
             goto end;
         }
     }
@@ -1282,6 +1284,7 @@ static int virtio_gpu_load(QEMUFile *f, void *opaque, size_t size,
                            const VMStateField *field)
 {
     VirtIOGPU *g = opaque;
+    Error *err = NULL;
     struct virtio_gpu_simple_resource *res;
     uint32_t resource_id, pformat;
     int i;
@@ -1317,7 +1320,8 @@ static int virtio_gpu_load(QEMUFile *f, void *opaque, size_t size,
                                              res->width,
                                              res->height,
                                              res->height ? res->hostmem / res->height : 0,
-                                             &error_warn)) {
+                                             &err)) {
+            warn_report_err(err);
             g_free(res);
             return -EINVAL;
         }
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 6b5b5dace3..7848e26278 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1289,6 +1289,8 @@ exit:
 
 static bool virtio_net_load_ebpf(VirtIONet *n, Error **errp)
 {
+    Error *err = NULL;
+
     if (!virtio_net_attach_ebpf_to_backend(n->nic, -1)) {
         return true;
     }
@@ -1306,7 +1308,11 @@ static bool virtio_net_load_ebpf(VirtIONet *n, Error **errp)
         return virtio_net_load_ebpf_fds(n, errp);
     }
 
-    ebpf_rss_load(&n->ebpf_rss, &error_warn);
+    ebpf_rss_load(&n->ebpf_rss, &err);
+    /* Beware, ebpf_rss_load() can return false with @err unset */
+    if (err) {
+        warn_report_err(err);
+    }
     return true;
 }
 
diff --git a/tests/unit/test-error-report.c b/tests/unit/test-error-report.c
index 54319c86c9..0cbde3c4cf 100644
--- a/tests/unit/test-error-report.c
+++ b/tests/unit/test-error-report.c
@@ -104,22 +104,6 @@ test_error_report_timestamp(void)
 ");
 }
 
-static void
-test_error_warn(void)
-{
-    if (g_test_subprocess()) {
-        error_setg(&error_warn, "Testing &error_warn");
-        return;
-    }
-
-    g_test_trap_subprocess(NULL, 0, 0);
-    g_test_trap_assert_passed();
-    g_test_trap_assert_stderr("\
-test-error-report: warning: Testing &error_warn*\
-");
-}
-
-
 int
 main(int argc, char *argv[])
 {
@@ -133,7 +117,6 @@ main(int argc, char *argv[])
     g_test_add_func("/error-report/glog", test_error_report_glog);
     g_test_add_func("/error-report/once", test_error_report_once);
     g_test_add_func("/error-report/timestamp", test_error_report_timestamp);
-    g_test_add_func("/error-report/warn", test_error_warn);
 
     return g_test_run();
 }
diff --git a/ui/gtk.c b/ui/gtk.c
index e91d093a49..9a08cadc88 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -1181,6 +1181,7 @@ static gboolean gd_touch_event(GtkWidget *widget, GdkEventTouch *touch,
                                void *opaque)
 {
     VirtualConsole *vc = opaque;
+    Error *err = NULL;
     uint64_t num_slot = GPOINTER_TO_UINT(touch->sequence);
     int type = -1;
 
@@ -1203,7 +1204,10 @@ static gboolean gd_touch_event(GtkWidget *widget, GdkEventTouch *touch,
     console_handle_touch_event(vc->gfx.dcl.con, touch_slots,
                                num_slot, surface_width(vc->gfx.ds),
                                surface_height(vc->gfx.ds), touch->x,
-                               touch->y, type, &error_warn);
+                               touch->y, type, &err);
+    if (err) {
+        warn_report_err(err);
+    }
     return TRUE;
 }
 
diff --git a/util/error.c b/util/error.c
index daea2142f3..0ae08225c0 100644
--- a/util/error.c
+++ b/util/error.c
@@ -19,7 +19,6 @@
 
 Error *error_abort;
 Error *error_fatal;
-Error *error_warn;
 
 static void error_handle(Error **errp, Error *err)
 {
@@ -41,9 +40,7 @@ static void error_handle(Error **errp, Error *err)
         error_report_err(err);
         exit(1);
     }
-    if (errp == &error_warn) {
-        warn_report_err(err);
-    } else if (errp && !*errp) {
+    if (errp && !*errp) {
         *errp = err;
     } else {
         error_free(err);
-- 
2.49.0