[Cython] remove timestamps from generated source files

Robert Bradshaw robertwb at gmail.com
Mon Jan 13 22:24:15 CET 2014

The timestamp is in a comment which ccache can strip before looking up
items in the cache; are you sure this is an issue?

On Mon, Jan 13, 2014 at 10:39 AM, Julian Taylor
<jtaylor.debian at googlemail.com> wrote:
> Hi,
> Cython currently places timestamps into all its generated C source files.
> This may be ok for developers who normally only rebuild files they
> changed anyway but it is a major annoyance for distribution packagers
> who often have to rebuild software from scratch including re-cythonizing.
> The reason this is annoying is that the adding of timestamps breaks
> caching of compiler results e.g. with ccache. Due to the size of the
> generated files recompiling the full sources normally takes a large
> fraction of the build time of packages.
> I'm not sure what purpose the timestamps really serve, the version
> number also included should be sufficient information in order to deduce
> its origin.
> Would it be possible to change Cython to stop putting timestamps into
> the source?
> I would also be happy if the granularity is reduced from seconds to
> hours/days or an non-default option to disable it (e.g. an environment
> variable).
> Additionally I think it might be useful to have a vendor id added to the
> version number added to the source files. This would allow easier origin
> tracking of files created with distribution patched versions of Cython.
> E.g. if Debian patches 0.20 of Cython it puts in
>  Generated by Cython 0.20 (Debian revision 3)
> Where the vendor id is added via a Distribution patch of the package and
> none is emitted for upstream builds.
> (CC. Debian maintainer of Cython for comments)
> Cheers,
> Julian Taylor
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