Re: [libvirt] [PATCH] virterror: Don't invoke error callback for ERR_OK

On Tue, Jan 12, 2010 at 03:57:33PM -0500, Cole Robinson wrote: > On 01/12/2010 03:48 PM, Daniel P. Berrange wrote: >> On Tue, Jan 12, 2010 at 03:26:28PM -0500, Cole Robinson wrote: >>> Since virDispatchError is now responsible for invoking the error callback, >>> give it the same semantics as ReportError, which will skip VIR_ERR_OK >>> (which is encountered when no error was raised). >>> >>> This fixes invoking the error callback after every non-erroring API call. >>> >>> Signed-off-by: Cole Robinson <crobinso(a)redhat.com&gt; >>> --- >>> src/util/virterror.c | 6 +++++- >>> 1 files changed, 5 insertions(+), 1 deletions(-) >>> >>> diff --git a/src/util/virterror.c b/src/util/virterror.c >>> index e2128b9..78974ee 100644 >>> --- a/src/util/virterror.c >>> +++ b/src/util/virterror.c >>> @@ -603,8 +603,12 @@ virDispatchError(virConnectPtr conn) >>> if (!err) >>> return; >>> >>> - /* Set a generic error message if none is already set */ >>> + /* We never used to raise ERR_OK, so maintain existing behavior */ >>> if (err->code == VIR_ERR_OK) >>> + return; >>> + >>> + /* Set a generic error message if none is already set */ >>> + if (!err->message) >>> virErrorGenericFailure(err); >>> >>> /* Copy the global error to per-connection error if needed */ >> >> We should only ever be invoking virDispatchError() in error paths, so >> if err->code == VIR_ERR_OK, this means we do need set a generic message >> because the earlier code indicated an error but forgot to report one. >> So I don't think this is correct. >> > > Ah, I think I wanted to check VIR_ERR_NONE here actually. > virDispatchError is called regardless of whether an error is actually > raised, so it may receive a zero'd out/empty virLastErrorObject, which > is what I'm trying to avoid reporting. I still don't think you are correct in that. If you run # grep --after 1 virDispatchError libvirt.c virDispatchError(NULL); return (-1); -- virDispatchError(net->conn); return -1; -- virDispatchError(NULL); return (-1); -- virDispatchError(pool->conn); return -1; Then all cases where virDispatchError() is called should be followed by the return of an error code, 99% of them are -1 or NULL. There are one or two where we use '0' for error as a special case. I don't see any places where virDispatchError() is called in a successful return path. So we should always be invoking the error callback, and ensuring an error is actually set before doing so.