[pacman-dev] [PATCH v2 2/2] Update the question callback

[Allan McRae]

On 24/06/14 20:18, Olivier Brunel wrote:
> On 06/24/14 08:14, Allan McRae wrote:
>> On 26/05/14 01:30, Andrew Gregory wrote:
>>> On 05/24/14 at 03:49pm, Olivier Brunel wrote:
>>>> Much like with events, instead of using a bunch of void* arguments for
>>>> all questions, we now send one pointer to an alpm_question_t struct.
>>>> This contains the type of question that was triggered.
>>>>
>>>> With this information, the pointer can then be typecasted to the
>>>> question-specific struct in order to get additional arguments.
>>>>
>>>> Signed-off-by: Olivier Brunel <jjk at jjacky.com>
>>>> ---
>>>>  lib/libalpm/alpm.h    |  92 +++++++++++++++++++++++++++++++++++++++--
>>>>  lib/libalpm/deps.c    |  38 ++++++++++-------
>>>>  lib/libalpm/handle.h  |   4 +-
>>>>  lib/libalpm/signing.c |  12 ++++--
>>>>  lib/libalpm/sync.c    |  60 +++++++++++++++++----------
>>>>  src/pacman/callback.c | 110 +++++++++++++++++++++++++++-----------------------
>>>>  src/pacman/callback.h |   3 +-
>>>>  7 files changed, 222 insertions(+), 97 deletions(-)
>>>
>>> The generic to specific struct casts cause Clang to fail when pacman
>>> is configured with --enable-warningflags:
>>>
>>>  callback.c:377:44: error: cast from 'alpm_question_t *' (aka 'struct
>>>        _alpm_question_t *') to 'alpm_question_install_ignorepkg_t *'
>>>        (aka 'struct _alpm_question_install_ignorepkg_t *') increases
>>>        required alignment from 4 to 8 [-Werror,-Wcast-align]
>>>    ...*q = (alpm_question_install_ignorepkg_t *) question;
>>>            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>
>>
>> These are silenced.
>>
>>> The earlier changes to the event callback have the same issue and also
>>> give errors about using non-literal strings with vprintf:
>>>
>>>  testdb.c:53:11: error: format string is not a string literal
>>>        [-Werror,-Wformat-nonliteral]
>>>                  vprintf(event->fmt, event->args);
>>>                          ^~~~~~~~~~
>>
>>
>> BAH!   Why did gcc no see this?
>>
>> Anyway, possible ways to fix this:
>>
>> 1)
>> +#pragma GCC diagnostic push
>> +#pragma GCC diagnostic ignored "-Wformat-nonliteral"
>>                 vprintf(event->fmt, event->args);
>> +#pragma GCC diagnostic pop
>>
>> This is crap because all clients that want to print a log message will
>> need to wrap their calls like this.
>>
>> 2)
>> Revert that change that made the logging an event.
>>
>>
>> Unless someone comes up with something else, I'll do the revert soon.
> 
> I can't think of another way to silence the warning, but there's a way
> to "work around" it: instead of putting fmt & args inside
> alpm_event_log_t, we put the resulting string (i.e. call pm_asprintf()
> in alpm and send the resulting string in the event).
> 
> No more false warnings then (but a malloc/free for each log event). I
> can send a patch if you'd like.
> 

Can not do that.   Translations of messages happen in the front-end.

Allan