Re: Does “${python3:Depends}” reliably generate correct dependencies?
On October 25, 2015 1:17:17 AM EDT, Ben Finney <ben+debian@benfinney.id.au> wrote:
>Howdy all,
>
>If we set “Depends: ${python3:Depends}” in the binary package, and use
>‘dh_python3’, is that all that is needed to ensure the correct
>dependencies on Python 3 versions?
>
>Recently I received this bug report (Bug#802889):
>
> please don't depend on all python3 versions, forcing the
> installation of all python versions shouldn't be enforced for a
> module.
>
> $ apt-cache show python3-coverage | grep Depends
> Depends: python3-pkg-resources, python3 (<< 3.6), python3 (>= 3.4~),
> python3.4, python3.5, libc6 (>= 2.4)
>
> <URL:https://bugs.debian.org/802889>
>
>So far as I can tell, these dependencies are generated because
>“Depends: […] ${python3:Depends}” is in that “Package” definition.
>
>On a Debian Sid system today, building a package for Python 3, along
>with its extension modules, means building it for all supported Python
>3
>versions. Are the above dependencies wrong for that?
>
>If the dependencies are incorrect, what should be used in the Depends
>field instead of “${python3:Depends}”?
>
>If the dependencies are correct, exactly what should I say in
>explanation to the reporter of Bug#802889?
Usually you only get the dependency on the specific python3 interpreters if there's a script with a shebang using that version. I'd check for that.
It could either be in the original source or due to dh_python3 doing something interesting in shebang rewriting (IIRC there's a known issue that P1otr is working on).
Scott K
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