[New-bugs-announce] [issue32773] distutils should NOT preserve timestamps

[Jeroen Demeyer]

New submission from Jeroen Demeyer <jdemeyer at cage.ugent.be>:

When a Python project is installed, distutils copies the files from the build to install directory using copy_file(). In this copy operation, timestamps are preserved. In other words, the timestamp of the installed file equals the timestamp of the source file.

By contrast, autotools does not preserve timestamps: the timestamp of the installed files equals the time of installation. This makes more sense because of dependency checking: if you reinstall a package, you typically want to rebuild everything depending on that package.

This issue is mostly relevant for installing .h files: most build systems (including distutils itself) provide a way to recompile C/C++ source files if they depend on a changed header file. But that only works if the timestamp of the header is updated when it is installed.

Note that ./command/build_py.py contains a comment

        # XXX copy_file by default preserves atime and mtime.  IMHO this is
        # the right thing to do, but perhaps it should be an option -- in
        # particular, a site administrator might want installed files to
        # reflect the time of installation rather than the last
        # modification time before the installed release.

but without justification.

----------
components: Distutils
messages: 311673
nosy: dstufft, eric.araujo, erik.bray, jdemeyer
priority: normal
severity: normal
status: open
title: distutils should NOT preserve timestamps
versions: Python 2.7, Python 3.4, Python 3.5, Python 3.6, Python 3.7, Python 3.8

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32773>
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