[v2] Less clumsy error checking

[PATCH v2 01/44] error: Improve examples in error.h's big comment

Markus Armbruster posted 44 patches 5 years, 7 months ago

Diff against v1 v3 v4
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Maintainers: Andrey Smirnov <andrew.smirnov@gmail.com>, Antony Pavlov <antonynpavlov@gmail.com>, Eric Blake <eblake@redhat.com>, Matthew Rosato <mjrosato@linux.ibm.com>, John Snow <jsnow@redhat.com>, Jason Wang <jasowang@redhat.com>, Richard Henderson <rth@twiddle.net>, Kevin Wolf <kwolf@redhat.com>, Paul Burton <pburton@wavecomp.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Zhang Chen <chen.zhang@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>, Cornelia Huck <cohuck@redhat.com>, Paul Durrant <paul@xen.org>, Christian Borntraeger <borntraeger@de.ibm.com>, David Hildenbrand <david@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Max Reitz <mreitz@redhat.com>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Joel Stanley <joel@jms.id.au>, Igor Mammedov <imammedo@redhat.com>, Andrew Baumann <Andrew.Baumann@microsoft.com>, Wen Congyang <wencongyang2@huawei.com>, Liu Yuan <namei.unix@gmail.com>, Laurent Vivier <lvivier@redhat.com>, Jeff Cody <codyprime@gmail.com>, Stefan Berger <stefanb@linux.ibm.com>, Riku Voipio <riku.voipio@iki.fi>, Ronnie Sahlberg <ronniesahlberg@gmail.com>, Ari Sundholm <ari@tuxera.com>, "Philippe Mathieu-Daudé" <philmd@redhat.com>, Jan Kiszka <jan.kiszka@web.de>, Michael Roth <mdroth@linux.vnet.ibm.com>, Alex Williamson <alex.williamson@redhat.com>, Li Zhijian <lizhijian@cn.fujitsu.com>, Beniamino Galvani <b.galvani@gmail.com>, Alistair Francis <alistair@alistair23.me>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Stefan Weil <sw@weilnetz.de>, Yoshinori Sato <ysato@users.sourceforge.jp>, Aurelien Jarno <aurelien@aurel32.net>, "Gonglei (Arei)" <arei.gonglei@huawei.com>, Leif Lindholm <leif@nuviainc.com>, "Hervé Poussineau" <hpoussin@reactos.org>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Peter Lieven <pl@kamp.de>, Eric Auger <eric.auger@redhat.com>, Xiao Guangrong <xiaoguangrong.eric@gmail.com>, Alberto Garcia <berto@igalia.com>, Niek Linnenbank <nieklinnenbank@gmail.com>, Xie Changlong <xiechanglong.d@gmail.com>, Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>, Markus Armbruster <armbru@redhat.com>, Stefano Stabellini <sstabellini@kernel.org>, Fam Zheng <fam@euphon.net>, "Daniel P. Berrangé" <berrange@redhat.com>, Sagar Karandikar <sagark@eecs.berkeley.edu>, Igor Mitsyanko <i.mitsyanko@gmail.com>, Gerd Hoffmann <kraxel@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Peter Chubb <peter.chubb@nicta.com.au>, "Denis V. Lunev" <den@openvz.org>, Halil Pasic <pasic@linux.ibm.com>, Anthony Perard <anthony.perard@citrix.com>, Andrew Jeffery <andrew@aj.id.au>, Jason Dillaman <dillaman@redhat.com>, Rob Herring <robh@kernel.org>, "Richard W.M. Jones" <rjones@redhat.com>, "Cédric Le Goater" <clg@kaod.org>, Subbaraya Sundeep <sundeep.lkml@gmail.com>, Peter Maydell <peter.maydell@linaro.org>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Jean-Christophe Dubois <jcd@tribudubois.net>, David Gibson <david@gibson.dropbear.id.au>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Radoslaw Biernacki <radoslaw.biernacki@linaro.org>, Thomas Huth <thuth@redhat.com>, Amit Shah <amit@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>

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[PATCH v2 01/44] error: Improve examples in error.h's big comment

Posted by Markus Armbruster 5 years, 7 months ago

Show errp instead of &err where &err is actually unusual.  Add a
missing declaration.  Add a second error pileup example.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
---
 include/qapi/error.h | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/include/qapi/error.h b/include/qapi/error.h
index ad5b6e896d..3e64324b7a 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -16,15 +16,15 @@
  * Error reporting system loosely patterned after Glib's GError.
  *
  * Create an error:
- *     error_setg(&err, "situation normal, all fouled up");
+ *     error_setg(errp, "situation normal, all fouled up");
  *
  * Create an error and add additional explanation:
- *     error_setg(&err, "invalid quark");
- *     error_append_hint(&err, "Valid quarks are up, down, strange, "
+ *     error_setg(errp, "invalid quark");
+ *     error_append_hint(errp, "Valid quarks are up, down, strange, "
  *                       "charm, top, bottom.\n");
  *
  * Do *not* contract this to
- *     error_setg(&err, "invalid quark\n"
+ *     error_setg(errp, "invalid quark\n" // WRONG!
  *                "Valid quarks are up, down, strange, charm, top, bottom.");
  *
  * Report an error to the current monitor if we have one, else stderr:
@@ -108,12 +108,23 @@
  *     }
  *
  * Do *not* "optimize" this to
+ *     Error *err = NULL;
  *     foo(arg, &err);
  *     bar(arg, &err); // WRONG!
  *     if (err) {
  *         handle the error...
  *     }
  * because this may pass a non-null err to bar().
+ *
+ * Likewise, do *not*
+ *     Error *err = NULL;
+ *     if (cond1) {
+ *         error_setg(&err, ...);
+ *     }
+ *     if (cond2) {
+ *         error_setg(&err, ...); // WRONG!
+ *     }
+ * because this may pass a non-null err to error_setg().
  */
 
 #ifndef ERROR_H
-- 
2.26.2