Re: [Qemu-devel] [PATCH] qemu-iotests: Fix _filter_qemu

[Stefan Hajnoczi <stefanha@redhat.com>]

On Tue, Apr 16, 2013 at 06:26:38AM -0600, Eric Blake wrote:
> On 04/16/2013 03:48 AM, Kevin Wolf wrote:
> > $QEMU_PROG happens to be 'qemu' in my setup, so this sed command
> > replaces a bit too much. Restrict it to the start of the line and to
> > when it's followed by a colon, i.e. the form used by error messages.
> > 
> > Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> > ---
> >  tests/qemu-iotests/common.filter | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tests/qemu-iotests/common.filter b/tests/qemu-iotests/common.filter
> > index bc5f250..a7f889a 100644
> > --- a/tests/qemu-iotests/common.filter
> > +++ b/tests/qemu-iotests/common.filter
> > @@ -155,7 +155,7 @@ _filter_qemu_io()
> >  # replace occurrences of QEMU_PROG with "qemu"
> >  _filter_qemu()
> >  {
> > -    sed -e "s#$(basename $QEMU_PROG)#QEMU_PROG#g"
> > +    sed -e "s#^$(basename $QEMU_PROG):#QEMU_PROG:#g"
> 
> Why spawn a basename process, when you can use shell to do the same?
> Also, the g modifier is worthless once you have a ^ anchor, since sed
> can only replace one ^ per line.  And you don't need sed's -e option for
> a single script.

sed -e is the convention in qemu-iotests.

Dropping the 'g' would be nice.

The problem with the POSIX shell string replacement is that the syntax
is horrible.  I can never remember what ${%}, ${%%}, ${#} and
%{##} do.  $(basename $QEMU_PROG) is clear (although it doesn't handle
spaces in the filename!).

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>