qemu/hw/xen
Markus Armbruster d2623129a7 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]
2020-05-15 07:07:58 +02:00
..
Makefile.objs xen: add a mechanism to automatically create XenDevice-s... 2019-01-14 13:45:40 +00:00
trace-events xen: perform XenDevice clean-up in XenBus watch handler 2019-09-24 12:18:47 +01:00
xen_devconfig.c Include sysemu/sysemu.h a lot less 2019-08-16 13:31:53 +02:00
xen_pt_config_init.c xen: re-name XenDevice to XenLegacyDevice... 2019-01-14 13:45:40 +00:00
xen_pt_graphics.c Avoid cpu_physical_memory_rw() with a constant is_write argument 2020-02-20 14:47:08 +01:00
xen_pt_load_rom.c hw/xen/xen_pt_load_rom: Remove unused includes 2020-02-27 11:50:30 +00:00
xen_pt_msi.c xen: re-name XenDevice to XenLegacyDevice... 2019-01-14 13:45:40 +00:00
xen_pt.c xen/pt: Fix flawed conversion to realize() 2020-04-29 08:01:52 +02:00
xen_pt.h misc: Replace zero-length arrays with flexible array member (automatic) 2020-03-16 22:07:42 +01:00
xen_pvdev.c Include qemu/main-loop.h less 2019-08-16 13:31:52 +02:00
xen-backend.c xen: add a mechanism to automatically create XenDevice-s... 2019-01-14 13:45:40 +00:00
xen-bus-helper.c Include hw/hw.h exactly where needed 2019-08-16 13:31:52 +02:00
xen-bus.c xen-bus/block: explicitly assign event channels to an AioContext 2020-02-27 11:50:30 +00:00
xen-common.c qom: Drop parameter @errp of object_property_add() & friends 2020-05-15 07:07:58 +02:00
xen-host-pci-device.c Include qemu-common.h exactly where needed 2019-06-12 13:20:20 +02:00
xen-host-pci-device.h Clean up decorations and whitespace around header guards 2016-07-12 16:20:46 +02:00
xen-legacy-backend.c qdev: set properties with device_class_set_props() 2020-01-24 20:59:15 +01:00