Re: [libvirt] [PATCH] virCapabilitiesDomainDataLookup: Produce saner error message
On 06/12/2015 03:49 PM, Michal Privoznik wrote:
During a review, I've noticed this error message that was
eventually
produced when I was trying to define a domain:
error: invalid argument: could not find capabilities for arch=mips64el
domaintype=(null)
Look at the (null). Why is it there? Well, during XML parsing, we try
to look up the default emulator for given OS type and possibly virt
type too. And this is the problem, because if we don't want to look up
by virt type, a -1 is passed to note this fact. Later, the code
handles -1 just right. Except for error message. When it is
constructed (in a very fabulous way I must say), the value is compared
to zero, not -1. And since we don't have any translation from -1 to a
virt type string, we just print (null).
Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com>
---
src/conf/capabilities.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/conf/capabilities.c b/src/conf/capabilities.c
index 6decde8..9c2c6b4 100644
--- a/src/conf/capabilities.c
+++ b/src/conf/capabilities.c
@@ -678,7 +678,7 @@ virCapabilitiesDomainDataLookupInternal(virCapsPtr caps,
virDomainOSTypeToString(ostype));
if (arch)
virBufferAsprintf(&buf, "arch=%s ", virArchToString(arch));
- if (domaintype)
+ if (domaintype != -1)
Well, this will work. However for some reason I
don't quite like this
way of handling it. We're trying to construct an error message and
because we didn't want to search by virttype we special-case this. I was
thinking more about introducing a new enum VIR_DOMAIN_VIRT_NONE which
will serve exactly this purpose (see virCapsDomainDataCompare,
comparison to arch :)). That way, we don't have to play with ternary in
here as pass VIRT_NONE right away:
...if (!(capsdata = virCapabilitiesDomainDataLookup(caps, def->os.type,
def->os.arch, use_virttype ? def->virtType : -1,
NULL, NULL)))...
Since XML parsing requires a domain to have a valid virttype defined, we
should be able to abuse the VIRT_NONE this way and stay a little
consistent in this particular code snippet of constructing an error
message. What do you think about it? If you think it's not worth it at
all, just drop the idea and push this one, it's an ACK.
virBufferAsprintf(&buf, "domaintype=%s ",
virDomainVirtTypeToString(domaintype));
if (emulator)
Erik