[php-maint] On php dependencies and lintian errors

[Antonio Ospite]

On Thu, 17 Mar 2016 16:51:06 +0100
Ondřej Surý <ondrej at sury.org> wrote:

> Hi Antonio,
>

Hi Ondřej,

> On Thu, Mar 17, 2016, at 16:29, Antonio Ospite wrote:
> > Hi,
> > 
> > I am the maintainer of tweeper[1] (I am also the upstream author BTW),
> > and since the introduction in Debian of the php7.0 packages I feet like
> > the dependencies of my package were a little too loose, let me explain
> > what I mean.
> > 
> > Right now tweeper dependencies are:
> > Depends: php5-cli, php5-curl, php5-xsl, php-xml-serializer
> > 
> > The package provides a tweeper executable with a shebang line which
> > says:
> >   #!/usr/bin/env php
> > 
> > Now, after I installed php7.0 I found out that tweeper didn't work
> > anymore with this error:
> > 
> >       PHP Fatal error:  Uncaught Error: Call to undefined function
> >       curl_init() in /usr/share/php/tweeper/tweeper.php:54
> > 
> > The problem was that the executable was using /usr/bin/php which now was
> > a link to php7.0, so even though all the _install_ dependencies were
> > satisfied (namely php5-curl), they didn't reflect the runtime
> > dependencies. Installing php7.0-curl worked around the issue but
> > I started looking at the right way to fix the problem.
> > 
> > The first thing I thought was to depend on the php-* packages, the ones
> > without the explicit version in the names, I tried that but lintian
> > complained with a message like this:
> > 
> > E: tweeper: php-script-but-no-phpX-cli-dep usr/share/php/tweeper/tweeper
> 
> Just ignore lintian for now. We will have to fix lintian at some point
> in time.
> 
> This was the most correct solution. Thank you for looking into it.
>

OK, thanks. Please consider fixing the lintian issue sooner rather than
later, it is rather confusing that lintian reports an as error what is
in fact the recommended practice.

> > However, even if there was not the lintian error, depending on the php-*
> > dependencies won't cover the case when a user switches the default php
> > interpreter version using the "alternatives" system; a user could end up
> > having all the right php7.0 install-time dependencies brought in by the
> > package but having /usr/bin/php point to php5 and and miss some run-time
> > dependencies, a situation symmetric to where I started.
> 
> That should not happen in stable release, as we will have only one
> version of PHP in stable release. So it's safe thing to do.
>

OK, thanks.

> > So I thought that a better fix would be to make sure to use, at
> > run-time, the php version which corresponds to the package dependencies,
> > e.g.: to add a patch to the package to make the executable use php5
> > explicitly in the shebang line:
> >   #!/usr/bin/env php5
> 
> Nope, php5 won't be present in stretch.
> 
> > But then I read that there are plans to ship stretch with just php7.0,
> > so an even better fix could be to use php7.0 in the executable and
> > depend on the php7.0-* packages, I tried that but lintian complains with
> > the same message from above
> 
> Please, don't do that as this would prevent future transitions.  Unless
> you feel that the PHP code in the package is so version specific that
> you'll have to rewrite it for each new PHP version anyway.
>
> > Should I file a bug against lintian to add support for php7.0-*
> > dependencies?
> 
> If you have time, please write up the draft of the bug and post it to
> the list, so we can finish it. Basically all php5-* should be turned
> into php-*.
>

I'll try to sketch a report.

> Every package with multiple extensions (with a grain of salt) now also
> have correct "Provides" for every extension inside, so you can even use
> that to finetune the dependencies.
>

Does that mean that lintian should allow both the php-* deps, which are
the recommended ones, and the phpX-* ones, which can be used for version
specific tuning?

Thanks,
   Antonio

-- 
Antonio Ospite
http://ao2.it

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?