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@redhat.com>
Jano