Re: [Qemu-devel] [PATCH 2/2] tracetool: Forbid argument name 'next'

["Lluís Vilanova" <vilanova@ac.upc.edu>]

Stefan Hajnoczi writes:

> On Mon, Mar 12, 2012 at 9:34 AM, Kevin Wolf <kwolf@redhat.com> wrote:
>> It has happened more than once that patches that look perfectly sane
>> and work with simpletrace broke systemtap because they use 'next' as an
>> argument name for a tracing function. However, 'next' is a keyword for
>> systemtap, so we shouldn't use it.
>> 
>> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
>> ---
>>  scripts/tracetool |    4 ++++
>>  1 files changed, 4 insertions(+), 0 deletions(-)
>> 
>> diff --git a/scripts/tracetool b/scripts/tracetool
>> index 4c9951d..f892af4 100755
>> --- a/scripts/tracetool
>> +++ b/scripts/tracetool
>> @@ -81,6 +81,10 @@ get_args()
>>     args=${1#*\(}
>>     args=${args%%\)*}
>>     echo "$args"
>> +
>> +    if (echo "$args" | grep "[ *]next\($\|[, ]\)" > /dev/null 2>&1); then
>> +        echo -e "\n#error 'next' is a bad argument name (clash with systemtap keyword)\n "
>> +    fi

> Good idea, let's prevent it from being used.

> I don't think this is the way to do it because callers will parse
> stdout and we're not guaranteed to be generating C code where #error
> works.  Instead, we can echo to stderr and do exit 1.

I'd rather wait for the python version of tracetool to be integrated, so that
less patches have to be rebased.

In addition, there's a nice 'error' routine to handle this type of cases.


Lluis

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