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diff --git a/doc/guix.texi b/doc/guix.texi index 1f6e0bb87a..74733f4fd1 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -12345,6 +12345,54 @@ starts with @code{py} (e.g. @code{pytz}), we keep it and prefix it as described above. +@subsubsection Specifying Dependencies +@cindex inputs, for Python packages + +Dependency information for Python packages is usually available in the +package source tree, with varying degrees of accuracy: in the +@file{setup.py} file, in @file{requirements.txt}, or in @file{tox.ini}. + +Your mission, when writing a recipe for a Python package, is to map +these dependencies to the appropriate type of ``input'' (@pxref{package +Reference, inputs}). Although the @code{pypi} importer normally does a +good job (@pxref{Invoking guix import}), you may want to check the +following check list to determine which dependency goes where. + +@itemize + +@item +Python dependencies required at run time go into +@code{propagated-inputs}. They are typically defined with the +@code{install_requires} keyword in @file{setup.py}, or in the +@file{requirements.txt} file. + +@item +Python packages required only at build time---e.g., those listed with +the @code{setup_requires} keyword in @file{setup.py}---or only for +testing---e.g., those in @code{tests_require}---go into +@code{native-inputs}. The rationale is that (1) they do not need to be +propagated because they are not needed at run time, and (2) in a +cross-compilation context, it's the ``native'' input that we'd want. + +Examples are @code{setuptools}, which is usually needed only at build +time, or the @code{pytest}, @code{mock}, and @code{nose} test +frameworks. Of course if any of these packages is also required at +run-time, it needs to go to @code{propagated-inputs}. + +@item +Anything that does not fall in the previous categories goes to +@code{inputs}, for example programs or C libraries required for building +Python packages containing C extensions. + +@item +If a Python package has optional dependencies (@code{extras_require}), +it is up to you to decide whether to add them or not, based on their +usefulness/overhead ratio (@pxref{Submitting Patches, @command{guix +size}}). + +@end itemize + + @node Perl Modules @subsection Perl Modules |