On a Tuesday in 2023, Michal Privoznik wrote:
There are few cases where virReportEnumRangeError() is passed to a
mismatching enum. With patch 4/4 we can check for this at compile time
(assuming -Wenum-compare is available).
For instance with clang I get:
FAILED: src/conf/libvirt_conf.a.p/domain_validate.c.o
clang ...
../src/conf/domain_validate.c:184:9: error: comparison of different enumeration types ('virDomainVideoBackendType' and 'virDomainInputType') [-Werror,-Wenum-compare]
virReportEnumRangeError(virDomainInputType, video->backend);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/util/virerror.h:175:47: note: expanded from macro 'virReportEnumRangeError'
(__typeof__(value))1 == (typname)1 && sizeof((typname)1) != 0 ? #typname : #typname)
~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~
Whereas with gcc I get more obscure error:
FAILED: src/conf/libvirt_conf.a.p/domain_validate.c.o
cc ...
In file included from ../src/util/virthread.h:25,
from ../src/util/virobject.h:25,
from ../src/conf/capabilities.h:28,
from ../src/conf/domain_conf.h:31,
from ../src/conf/domain_validate.h:25,
from ../src/conf/domain_validate.c:23:
../src/conf/domain_validate.c: In function ‘virDomainVideoDefValidate’:
../src/util/virerror.h:175:47: error: comparison between ‘enum <anonymous>’ and ‘enum <anonymous>’ [-Werror=enum-compare]
175 | (__typeof__(value))1 == (typname)1 && sizeof((typname)1) != 0 ? #typname : #typname)
| ^~
../src/conf/domain_validate.c:184:9: note: in expansion of macro ‘virReportEnumRangeError’
184 | virReportEnumRangeError(virDomainInputType, video->backend);
| ^~~~~~~~~~~~~~~~~~~~~~~
But I guess this is also okay-ish - it reports there is a problem with
code.
NB this only works with variables that are of a certain enum types. It
does not work with those generic 'int var /* someEnum */' declarations,
understandably. But as we use virXMLPropEnum() more, we can declare
variables of their true type (enum) and get more and more calls to
virReportEnumRangeError() checked.
Michal Prívozník (4):
virnetdevvportprofile: Turn virNetDevVPortProfileLinkOp enum into a
proper typedef
virNetDevVPortProfileOp8021Qbh: Use proper type in
virReportEnumRangeError()
virDomainVideoDefValidate: Use proper type in
virReportEnumRangeError()
virerror: Make virReportEnumRangeError() check for type mismatch
src/conf/domain_validate.c | 2 +-
src/util/virerror.h | 14 ++++++++------
src/util/virnetdevvportprofile.c | 10 +++++-----
3 files changed, 14 insertions(+), 12 deletions(-)
Reviewed-by: Ján Tomko <jtomko@xxxxxxxxxx> Jano
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