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* doc/contributing.texi (Submitting Patches): Remove powerpc-linux examples. * doc/guix.texi (Virtualization Services): Replace powerpc-linux example with mips64el-linux.
987 lines
40 KiB
Text
987 lines
40 KiB
Text
@node Contributing
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@chapter Contributing
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This project is a cooperative effort, and we need your help to make it
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grow! Please get in touch with us on @email{guix-devel@@gnu.org} and
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@code{#guix} on the Freenode IRC network. We welcome ideas, bug
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reports, patches, and anything that may be helpful to the project. We
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particularly welcome help on packaging (@pxref{Packaging Guidelines}).
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@cindex code of conduct, of contributors
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@cindex contributor covenant
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We want to provide a warm, friendly, and harassment-free environment, so
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that anyone can contribute to the best of their abilities. To this end
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our project uses a ``Contributor Covenant'', which was adapted from
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@url{http://contributor-covenant.org/}. You can find a local version in
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the @file{CODE-OF-CONDUCT} file in the source tree.
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Contributors are not required to use their legal name in patches and
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on-line communication; they can use any name or pseudonym of their
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choice.
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@menu
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* Building from Git:: The latest and greatest.
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* Running Guix Before It Is Installed:: Hacker tricks.
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* The Perfect Setup:: The right tools.
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* Packaging Guidelines:: Growing the distribution.
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* Coding Style:: Hygiene of the contributor.
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* Submitting Patches:: Share your work.
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@end menu
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@node Building from Git
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@section Building from Git
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If you want to hack Guix itself, it is recommended to use the latest
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version from the Git repository:
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@example
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git clone https://git.savannah.gnu.org/git/guix.git
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@end example
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When building Guix from a checkout,
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the following packages are required in addition to those mentioned in
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the installation instructions (@pxref{Requirements}).
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@itemize
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@item @url{http://gnu.org/software/autoconf/, GNU Autoconf};
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@item @url{http://gnu.org/software/automake/, GNU Automake};
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@item @url{http://gnu.org/software/gettext/, GNU Gettext};
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@item @url{http://gnu.org/software/texinfo/, GNU Texinfo};
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@item @url{http://www.graphviz.org/, Graphviz};
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@item @url{http://www.gnu.org/software/help2man/, GNU Help2man (optional)}.
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@end itemize
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The easiest way to set up a development environment for Guix is, of
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course, by using Guix! The following command starts a new shell where
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all the dependencies and appropriate environment variables are set up to
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hack on Guix:
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@example
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guix environment guix
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@end example
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@xref{Invoking guix environment}, for more information on that command.
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Extra dependencies can be added with @option{--ad-hoc}:
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@example
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guix environment guix --ad-hoc help2man git strace
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@end example
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Run @command{./bootstrap} to generate the build system infrastructure
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using Autoconf and Automake. If you get an error like this one:
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@example
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configure.ac:46: error: possibly undefined macro: PKG_CHECK_MODULES
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@end example
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@noindent
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it probably means that Autoconf couldn’t find @file{pkg.m4}, which is
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provided by pkg-config. Make sure that @file{pkg.m4} is available. The
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same holds for the @file{guile.m4} set of macros provided by Guile. For
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instance, if you installed Automake in @file{/usr/local}, it wouldn’t
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look for @file{.m4} files in @file{/usr/share}. In that case, you have
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to invoke the following command:
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@example
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export ACLOCAL_PATH=/usr/share/aclocal
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@end example
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@xref{Macro Search Path,,, automake, The GNU Automake Manual}, for
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more information.
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Then, run @command{./configure} as usual. Make sure to pass
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@code{--localstatedir=@var{directory}} where @var{directory} is the
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@code{localstatedir} value used by your current installation (@pxref{The
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Store}, for information about this).
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Finally, you have to invoke @code{make check} to run tests
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(@pxref{Running the Test Suite}). If anything
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fails, take a look at installation instructions (@pxref{Installation})
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or send a message to the @email{guix-devel@@gnu.org, mailing list}.
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@node Running Guix Before It Is Installed
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@section Running Guix Before It Is Installed
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In order to keep a sane working environment, you will find it useful to
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test the changes made in your local source tree checkout without
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actually installing them. So that you can distinguish between your
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``end-user'' hat and your ``motley'' costume.
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To that end, all the command-line tools can be used even if you have not
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run @code{make install}. To do that, you first need to have an environment
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with all the dependencies available (@pxref{Building from Git}), and then
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simply prefix each command with
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@command{./pre-inst-env} (the @file{pre-inst-env} script lives in the
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top build tree of Guix; it is generated by @command{./configure}),
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as in@footnote{The @option{-E} flag to
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@command{sudo} guarantees that @code{GUILE_LOAD_PATH} is correctly set
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such that @command{guix-daemon} and the tools it uses can find the Guile
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modules they need.}:
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@example
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$ sudo -E ./pre-inst-env guix-daemon --build-users-group=guixbuild
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$ ./pre-inst-env guix build hello
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@end example
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@noindent
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Similarly, for a Guile session using the Guix modules:
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@example
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$ ./pre-inst-env guile -c '(use-modules (guix utils)) (pk (%current-system))'
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;;; ("x86_64-linux")
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@end example
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@noindent
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@cindex REPL
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@cindex read-eval-print loop
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@dots{} and for a REPL (@pxref{Using Guile Interactively,,, guile, Guile
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Reference Manual}):
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@example
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$ ./pre-inst-env guile
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scheme@@(guile-user)> ,use(guix)
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scheme@@(guile-user)> ,use(gnu)
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scheme@@(guile-user)> (define snakes
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(fold-packages
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(lambda (package lst)
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(if (string-prefix? "python"
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(package-name package))
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(cons package lst)
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lst))
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'()))
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scheme@@(guile-user)> (length snakes)
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$1 = 361
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@end example
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The @command{pre-inst-env} script sets up all the environment variables
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necessary to support this, including @env{PATH} and @env{GUILE_LOAD_PATH}.
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Note that @command{./pre-inst-env guix pull} does @emph{not} upgrade the
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local source tree; it simply updates the @file{~/.config/guix/current}
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symlink (@pxref{Invoking guix pull}). Run @command{git pull} instead if
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you want to upgrade your local source tree.
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@node The Perfect Setup
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@section The Perfect Setup
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The Perfect Setup to hack on Guix is basically the perfect setup used
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for Guile hacking (@pxref{Using Guile in Emacs,,, guile, Guile Reference
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Manual}). First, you need more than an editor, you need
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@url{http://www.gnu.org/software/emacs, Emacs}, empowered by the
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wonderful @url{http://nongnu.org/geiser/, Geiser}. To set that up, run:
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@example
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guix package -i emacs guile emacs-geiser
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@end example
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Geiser allows for interactive and incremental development from within
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Emacs: code compilation and evaluation from within buffers, access to
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on-line documentation (docstrings), context-sensitive completion,
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@kbd{M-.} to jump to an object definition, a REPL to try out your code,
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and more (@pxref{Introduction,,, geiser, Geiser User Manual}). For
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convenient Guix development, make sure to augment Guile’s load path so
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that it finds source files from your checkout:
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@lisp
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;; @r{Assuming the Guix checkout is in ~/src/guix.}
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(with-eval-after-load 'geiser-guile
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(add-to-list 'geiser-guile-load-path "~/src/guix"))
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@end lisp
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To actually edit the code, Emacs already has a neat Scheme mode. But in
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addition to that, you must not miss
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@url{http://www.emacswiki.org/emacs/ParEdit, Paredit}. It provides
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facilities to directly operate on the syntax tree, such as raising an
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s-expression or wrapping it, swallowing or rejecting the following
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s-expression, etc.
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@cindex code snippets
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@cindex templates
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@cindex reducing boilerplate
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We also provide templates for common git commit messages and package
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definitions in the @file{etc/snippets} directory. These templates can
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be used with @url{http://joaotavora.github.io/yasnippet/, YASnippet} to
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expand short trigger strings to interactive text snippets. You may want
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to add the snippets directory to the @var{yas-snippet-dirs} variable in
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Emacs.
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@lisp
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;; @r{Assuming the Guix checkout is in ~/src/guix.}
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(with-eval-after-load 'yasnippet
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(add-to-list 'yas-snippet-dirs "~/src/guix/etc/snippets"))
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@end lisp
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The commit message snippets depend on @url{https://magit.vc/, Magit} to
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display staged files. When editing a commit message type @code{add}
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followed by @kbd{TAB} to insert a commit message template for adding a
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package; type @code{update} followed by @kbd{TAB} to insert a template
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for updating a package; type @code{https} followed by @kbd{TAB} to
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insert a template for changing the home page URI of a package to HTTPS.
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The main snippet for @code{scheme-mode} is triggered by typing
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@code{package...} followed by @kbd{TAB}. This snippet also inserts the
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trigger string @code{origin...}, which can be expanded further. The
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@code{origin} snippet in turn may insert other trigger strings ending on
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@code{...}, which also can be expanded further.
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@node Packaging Guidelines
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@section Packaging Guidelines
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@cindex packages, creating
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The GNU distribution is nascent and may well lack some of your favorite
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packages. This section describes how you can help make the distribution
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grow.
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Free software packages are usually distributed in the form of
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@dfn{source code tarballs}---typically @file{tar.gz} files that contain
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all the source files. Adding a package to the distribution means
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essentially two things: adding a @dfn{recipe} that describes how to
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build the package, including a list of other packages required to build
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it, and adding @dfn{package metadata} along with that recipe, such as a
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description and licensing information.
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In Guix all this information is embodied in @dfn{package definitions}.
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Package definitions provide a high-level view of the package. They are
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written using the syntax of the Scheme programming language; in fact,
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for each package we define a variable bound to the package definition,
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and export that variable from a module (@pxref{Package Modules}).
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However, in-depth Scheme knowledge is @emph{not} a prerequisite for
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creating packages. For more information on package definitions,
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@pxref{Defining Packages}.
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Once a package definition is in place, stored in a file in the Guix
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source tree, it can be tested using the @command{guix build} command
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(@pxref{Invoking guix build}). For example, assuming the new package is
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called @code{gnew}, you may run this command from the Guix build tree
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(@pxref{Running Guix Before It Is Installed}):
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@example
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./pre-inst-env guix build gnew --keep-failed
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@end example
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Using @code{--keep-failed} makes it easier to debug build failures since
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it provides access to the failed build tree. Another useful
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command-line option when debugging is @code{--log-file}, to access the
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build log.
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If the package is unknown to the @command{guix} command, it may be that
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the source file contains a syntax error, or lacks a @code{define-public}
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clause to export the package variable. To figure it out, you may load
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the module from Guile to get more information about the actual error:
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@example
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./pre-inst-env guile -c '(use-modules (gnu packages gnew))'
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@end example
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Once your package builds correctly, please send us a patch
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(@pxref{Submitting Patches}). Well, if you need help, we will be happy to
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help you too. Once the patch is committed in the Guix repository, the
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new package automatically gets built on the supported platforms by
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@url{http://hydra.gnu.org/jobset/gnu/master, our continuous integration
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system}.
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@cindex substituter
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Users can obtain the new package definition simply by running
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@command{guix pull} (@pxref{Invoking guix pull}). When
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@code{@value{SUBSTITUTE-SERVER}} is done building the package, installing the
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package automatically downloads binaries from there
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(@pxref{Substitutes}). The only place where human intervention is
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needed is to review and apply the patch.
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@menu
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* Software Freedom:: What may go into the distribution.
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* Package Naming:: What's in a name?
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* Version Numbers:: When the name is not enough.
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* Synopses and Descriptions:: Helping users find the right package.
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* Python Modules:: A touch of British comedy.
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* Perl Modules:: Little pearls.
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* Java Packages:: Coffee break.
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* Fonts:: Fond of fonts.
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@end menu
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@node Software Freedom
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@subsection Software Freedom
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@c Adapted from http://www.gnu.org/philosophy/philosophy.html.
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@cindex free software
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The GNU operating system has been developed so that users can have
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freedom in their computing. GNU is @dfn{free software}, meaning that
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users have the @url{http://www.gnu.org/philosophy/free-sw.html,four
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essential freedoms}: to run the program, to study and change the program
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in source code form, to redistribute exact copies, and to distribute
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modified versions. Packages found in the GNU distribution provide only
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software that conveys these four freedoms.
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In addition, the GNU distribution follow the
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@url{http://www.gnu.org/distros/free-system-distribution-guidelines.html,free
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software distribution guidelines}. Among other things, these guidelines
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reject non-free firmware, recommendations of non-free software, and
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discuss ways to deal with trademarks and patents.
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Some otherwise free upstream package sources contain a small and optional
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subset that violates the above guidelines, for instance because this subset
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is itself non-free code. When that happens, the offending items are removed
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with appropriate patches or code snippets in the @code{origin} form of the
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package (@pxref{Defining Packages}). This way, @code{guix
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build --source} returns the ``freed'' source rather than the unmodified
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upstream source.
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@node Package Naming
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@subsection Package Naming
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@cindex package name
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A package has actually two names associated with it:
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First, there is the name of the @emph{Scheme variable}, the one following
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@code{define-public}. By this name, the package can be made known in the
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Scheme code, for instance as input to another package. Second, there is
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the string in the @code{name} field of a package definition. This name
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is used by package management commands such as
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@command{guix package} and @command{guix build}.
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Both are usually the same and correspond to the lowercase conversion of
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the project name chosen upstream, with underscores replaced with
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hyphens. For instance, GNUnet is available as @code{gnunet}, and
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SDL_net as @code{sdl-net}.
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We do not add @code{lib} prefixes for library packages, unless these are
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already part of the official project name. But @pxref{Python
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Modules} and @ref{Perl Modules} for special rules concerning modules for
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the Python and Perl languages.
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Font package names are handled differently, @pxref{Fonts}.
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@node Version Numbers
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@subsection Version Numbers
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@cindex package version
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We usually package only the latest version of a given free software
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project. But sometimes, for instance for incompatible library versions,
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two (or more) versions of the same package are needed. These require
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different Scheme variable names. We use the name as defined
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in @ref{Package Naming}
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for the most recent version; previous versions use the same name, suffixed
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by @code{-} and the smallest prefix of the version number that may
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distinguish the two versions.
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The name inside the package definition is the same for all versions of a
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package and does not contain any version number.
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For instance, the versions 2.24.20 and 3.9.12 of GTK+ may be packaged as follows:
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@example
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(define-public gtk+
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(package
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(name "gtk+")
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(version "3.9.12")
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...))
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(define-public gtk+-2
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(package
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(name "gtk+")
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(version "2.24.20")
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...))
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@end example
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If we also wanted GTK+ 3.8.2, this would be packaged as
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@example
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(define-public gtk+-3.8
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(package
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(name "gtk+")
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(version "3.8.2")
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...))
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@end example
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@c See <https://lists.gnu.org/archive/html/guix-devel/2016-01/msg00425.html>,
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@c for a discussion of what follows.
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@cindex version number, for VCS snapshots
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Occasionally, we package snapshots of upstream's version control system
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(VCS) instead of formal releases. This should remain exceptional,
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because it is up to upstream developers to clarify what the stable
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release is. Yet, it is sometimes necessary. So, what should we put in
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the @code{version} field?
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Clearly, we need to make the commit identifier of the VCS snapshot
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visible in the version string, but we also need to make sure that the
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version string is monotonically increasing so that @command{guix package
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--upgrade} can determine which version is newer. Since commit
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identifiers, notably with Git, are not monotonically increasing, we add
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a revision number that we increase each time we upgrade to a newer
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snapshot. The resulting version string looks like this:
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|
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@example
|
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2.0.11-3.cabba9e
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^ ^ ^
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| | `-- upstream commit ID
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| |
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| `--- Guix package revision
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|
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latest upstream version
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@end example
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It is a good idea to strip commit identifiers in the @code{version}
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field to, say, 7 digits. It avoids an aesthetic annoyance (assuming
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aesthetics have a role to play here) as well as problems related to OS
|
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limits such as the maximum shebang length (127 bytes for the Linux
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kernel.) It is best to use the full commit identifiers in
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@code{origin}s, though, to avoid ambiguities. A typical package
|
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definition may look like this:
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|
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@example
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(define my-package
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(let ((commit "c3f29bc928d5900971f65965feaae59e1272a3f7")
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(revision "1")) ;Guix package revision
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(package
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(version (git-version "0.9" revision commit))
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(source (origin
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(method git-fetch)
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(uri (git-reference
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(url "git://example.org/my-package.git")
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(commit commit)))
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(sha256 (base32 "1mbikn@dots{}"))
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(file-name (git-file-name name version))))
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;; @dots{}
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)))
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@end example
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@node Synopses and Descriptions
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@subsection Synopses and Descriptions
|
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|
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@cindex package description
|
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@cindex package synopsis
|
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As we have seen before, each package in GNU@tie{}Guix includes a
|
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synopsis and a description (@pxref{Defining Packages}). Synopses and
|
||
descriptions are important: They are what @command{guix package
|
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--search} searches, and a crucial piece of information to help users
|
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determine whether a given package suits their needs. Consequently,
|
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packagers should pay attention to what goes into them.
|
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|
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Synopses must start with a capital letter and must not end with a
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period. They must not start with ``a'' or ``the'', which usually does
|
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not bring anything; for instance, prefer ``File-frobbing tool'' over ``A
|
||
tool that frobs files''. The synopsis should say what the package
|
||
is---e.g., ``Core GNU utilities (file, text, shell)''---or what it is
|
||
used for---e.g., the synopsis for GNU@tie{}grep is ``Print lines
|
||
matching a pattern''.
|
||
|
||
Keep in mind that the synopsis must be meaningful for a very wide
|
||
audience. For example, ``Manipulate alignments in the SAM format''
|
||
might make sense for a seasoned bioinformatics researcher, but might be
|
||
fairly unhelpful or even misleading to a non-specialized audience. It
|
||
is a good idea to come up with a synopsis that gives an idea of the
|
||
application domain of the package. In this example, this might give
|
||
something like ``Manipulate nucleotide sequence alignments'', which
|
||
hopefully gives the user a better idea of whether this is what they are
|
||
looking for.
|
||
|
||
Descriptions should take between five and ten lines. Use full
|
||
sentences, and avoid using acronyms without first introducing them.
|
||
Please avoid marketing phrases such as ``world-leading'',
|
||
``industrial-strength'', and ``next-generation'', and avoid superlatives
|
||
like ``the most advanced''---they are not helpful to users looking for a
|
||
package and may even sound suspicious. Instead, try to be factual,
|
||
mentioning use cases and features.
|
||
|
||
@cindex Texinfo markup, in package descriptions
|
||
Descriptions can include Texinfo markup, which is useful to introduce
|
||
ornaments such as @code{@@code} or @code{@@dfn}, bullet lists, or
|
||
hyperlinks (@pxref{Overview,,, texinfo, GNU Texinfo}). However you
|
||
should be careful when using some characters for example @samp{@@} and
|
||
curly braces which are the basic special characters in Texinfo
|
||
(@pxref{Special Characters,,, texinfo, GNU Texinfo}). User interfaces
|
||
such as @command{guix package --show} take care of rendering it
|
||
appropriately.
|
||
|
||
Synopses and descriptions are translated by volunteers
|
||
@uref{http://translationproject.org/domain/guix-packages.html, at the
|
||
Translation Project} so that as many users as possible can read them in
|
||
their native language. User interfaces search them and display them in
|
||
the language specified by the current locale.
|
||
|
||
To allow @command{xgettext} to extract them as translatable strings,
|
||
synopses and descriptions @emph{must be literal strings}. This means
|
||
that you cannot use @code{string-append} or @code{format} to construct
|
||
these strings:
|
||
|
||
@lisp
|
||
(package
|
||
;; @dots{}
|
||
(synopsis "This is translatable")
|
||
(description (string-append "This is " "*not*" " translatable.")))
|
||
@end lisp
|
||
|
||
Translation is a lot of work so, as a packager, please pay even more
|
||
attention to your synopses and descriptions as every change may entail
|
||
additional work for translators. In order to help them, it is possible
|
||
to make recommendations or instructions visible to them by inserting
|
||
special comments like this (@pxref{xgettext Invocation,,, gettext, GNU
|
||
Gettext}):
|
||
|
||
@example
|
||
;; TRANSLATORS: "X11 resize-and-rotate" should not be translated.
|
||
(description "ARandR is designed to provide a simple visual front end
|
||
for the X11 resize-and-rotate (RandR) extension. @dots{}")
|
||
@end example
|
||
|
||
|
||
@node Python Modules
|
||
@subsection Python Modules
|
||
|
||
@cindex python
|
||
We currently package Python 2 and Python 3, under the Scheme variable names
|
||
@code{python-2} and @code{python} as explained in @ref{Version Numbers}.
|
||
To avoid confusion and naming clashes with other programming languages, it
|
||
seems desirable that the name of a package for a Python module contains
|
||
the word @code{python}.
|
||
|
||
Some modules are compatible with only one version of Python, others with both.
|
||
If the package Foo compiles only with Python 3, we name it
|
||
@code{python-foo}; if it compiles only with Python 2, we name it
|
||
@code{python2-foo}. If it is compatible with both versions, we create two
|
||
packages with the corresponding names.
|
||
|
||
If a project already contains the word @code{python}, we drop this;
|
||
for instance, the module python-dateutil is packaged under the names
|
||
@code{python-dateutil} and @code{python2-dateutil}. If the project name
|
||
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
|
||
We currently package Python 2 with @code{setuptools} and @code{pip}
|
||
installed like Python 3.4 has per default. Thus you don't need to
|
||
specify either of these as an input. @command{guix lint} will warn you
|
||
if you do.
|
||
|
||
@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 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
|
||
|
||
@cindex perl
|
||
Perl programs standing for themselves are named as any other package,
|
||
using the lowercase upstream name.
|
||
For Perl packages containing a single class, we use the lowercase class name,
|
||
replace all occurrences of @code{::} by dashes and prepend the prefix
|
||
@code{perl-}.
|
||
So the class @code{XML::Parser} becomes @code{perl-xml-parser}.
|
||
Modules containing several classes keep their lowercase upstream name and
|
||
are also prepended by @code{perl-}. Such modules tend to have the word
|
||
@code{perl} somewhere in their name, which gets dropped in favor of the
|
||
prefix. For instance, @code{libwww-perl} becomes @code{perl-libwww}.
|
||
|
||
|
||
@node Java Packages
|
||
@subsection Java Packages
|
||
|
||
@cindex java
|
||
Java programs standing for themselves are named as any other package,
|
||
using the lowercase upstream name.
|
||
|
||
To avoid confusion and naming clashes with other programming languages,
|
||
it is desirable that the name of a package for a Java package is
|
||
prefixed with @code{java-}. If a project already contains the word
|
||
@code{java}, we drop this; for instance, the package @code{ngsjava} is
|
||
packaged under the name @code{java-ngs}.
|
||
|
||
For Java packages containing a single class or a small class hierarchy,
|
||
we use the lowercase class name, replace all occurrences of @code{.} by
|
||
dashes and prepend the prefix @code{java-}. So the class
|
||
@code{apache.commons.cli} becomes package
|
||
@code{java-apache-commons-cli}.
|
||
|
||
|
||
@node Fonts
|
||
@subsection Fonts
|
||
|
||
@cindex fonts
|
||
For fonts that are in general not installed by a user for typesetting
|
||
purposes, or that are distributed as part of a larger software package,
|
||
we rely on the general packaging rules for software; for instance, this
|
||
applies to the fonts delivered as part of the X.Org system or fonts that
|
||
are part of TeX Live.
|
||
|
||
To make it easier for a user to search for fonts, names for other packages
|
||
containing only fonts are constructed as follows, independently of the
|
||
upstream package name.
|
||
|
||
The name of a package containing only one font family starts with
|
||
@code{font-}; it is followed by the foundry name and a dash @code{-}
|
||
if the foundry is known, and the font family name, in which spaces are
|
||
replaced by dashes (and as usual, all upper case letters are transformed
|
||
to lower case).
|
||
For example, the Gentium font family by SIL is packaged under the name
|
||
@code{font-sil-gentium}.
|
||
|
||
For a package containing several font families, the name of the collection
|
||
is used in the place of the font family name.
|
||
For instance, the Liberation fonts consist of three families,
|
||
Liberation Sans, Liberation Serif and Liberation Mono.
|
||
These could be packaged separately under the names
|
||
@code{font-liberation-sans} and so on; but as they are distributed together
|
||
under a common name, we prefer to package them together as
|
||
@code{font-liberation}.
|
||
|
||
In the case where several formats of the same font family or font collection
|
||
are packaged separately, a short form of the format, prepended by a dash,
|
||
is added to the package name. We use @code{-ttf} for TrueType fonts,
|
||
@code{-otf} for OpenType fonts and @code{-type1} for PostScript Type 1
|
||
fonts.
|
||
|
||
|
||
@node Coding Style
|
||
@section Coding Style
|
||
|
||
In general our code follows the GNU Coding Standards (@pxref{Top,,,
|
||
standards, GNU Coding Standards}). However, they do not say much about
|
||
Scheme, so here are some additional rules.
|
||
|
||
@menu
|
||
* Programming Paradigm:: How to compose your elements.
|
||
* Modules:: Where to store your code?
|
||
* Data Types and Pattern Matching:: Implementing data structures.
|
||
* Formatting Code:: Writing conventions.
|
||
@end menu
|
||
|
||
@node Programming Paradigm
|
||
@subsection Programming Paradigm
|
||
|
||
Scheme code in Guix is written in a purely functional style. One
|
||
exception is code that involves input/output, and procedures that
|
||
implement low-level concepts, such as the @code{memoize} procedure.
|
||
|
||
@node Modules
|
||
@subsection Modules
|
||
|
||
Guile modules that are meant to be used on the builder side must live in
|
||
the @code{(guix build @dots{})} name space. They must not refer to
|
||
other Guix or GNU modules. However, it is OK for a ``host-side'' module
|
||
to use a build-side module.
|
||
|
||
Modules that deal with the broader GNU system should be in the
|
||
@code{(gnu @dots{})} name space rather than @code{(guix @dots{})}.
|
||
|
||
@node Data Types and Pattern Matching
|
||
@subsection Data Types and Pattern Matching
|
||
|
||
The tendency in classical Lisp is to use lists to represent everything,
|
||
and then to browse them ``by hand'' using @code{car}, @code{cdr},
|
||
@code{cadr}, and co. There are several problems with that style,
|
||
notably the fact that it is hard to read, error-prone, and a hindrance
|
||
to proper type error reports.
|
||
|
||
Guix code should define appropriate data types (for instance, using
|
||
@code{define-record-type*}) rather than abuse lists. In addition, it
|
||
should use pattern matching, via Guile’s @code{(ice-9 match)} module,
|
||
especially when matching lists.
|
||
|
||
@node Formatting Code
|
||
@subsection Formatting Code
|
||
|
||
@cindex formatting code
|
||
@cindex coding style
|
||
When writing Scheme code, we follow common wisdom among Scheme
|
||
programmers. In general, we follow the
|
||
@url{http://mumble.net/~campbell/scheme/style.txt, Riastradh's Lisp
|
||
Style Rules}. This document happens to describe the conventions mostly
|
||
used in Guile’s code too. It is very thoughtful and well written, so
|
||
please do read it.
|
||
|
||
Some special forms introduced in Guix, such as the @code{substitute*}
|
||
macro, have special indentation rules. These are defined in the
|
||
@file{.dir-locals.el} file, which Emacs automatically uses. Also note
|
||
that Emacs-Guix provides @code{guix-devel-mode} mode that indents and
|
||
highlights Guix code properly (@pxref{Development,,, emacs-guix, The
|
||
Emacs-Guix Reference Manual}).
|
||
|
||
@cindex indentation, of code
|
||
@cindex formatting, of code
|
||
If you do not use Emacs, please make sure to let your editor knows these
|
||
rules. To automatically indent a package definition, you can also run:
|
||
|
||
@example
|
||
./etc/indent-code.el gnu/packages/@var{file}.scm @var{package}
|
||
@end example
|
||
|
||
@noindent
|
||
This automatically indents the definition of @var{package} in
|
||
@file{gnu/packages/@var{file}.scm} by running Emacs in batch mode. To
|
||
indent a whole file, omit the second argument:
|
||
|
||
@example
|
||
./etc/indent-code.el gnu/services/@var{file}.scm
|
||
@end example
|
||
|
||
@cindex Vim, Scheme code editing
|
||
If you are editing code with Vim, we recommend that you run @code{:set
|
||
autoindent} so that your code is automatically indented as you type.
|
||
Additionally,
|
||
@uref{https://www.vim.org/scripts/script.php?script_id=3998,
|
||
@code{paredit.vim}} may help you deal with all these parentheses.
|
||
|
||
We require all top-level procedures to carry a docstring. This
|
||
requirement can be relaxed for simple private procedures in the
|
||
@code{(guix build @dots{})} name space, though.
|
||
|
||
Procedures should not have more than four positional parameters. Use
|
||
keyword parameters for procedures that take more than four parameters.
|
||
|
||
|
||
@node Submitting Patches
|
||
@section Submitting Patches
|
||
|
||
Development is done using the Git distributed version control system.
|
||
Thus, access to the repository is not strictly necessary. We welcome
|
||
contributions in the form of patches as produced by @code{git
|
||
format-patch} sent to the @email{guix-patches@@gnu.org} mailing list.
|
||
|
||
This mailing list is backed by a Debbugs instance accessible at
|
||
@uref{https://bugs.gnu.org/guix-patches}, which allows us to keep track
|
||
of submissions. Each message sent to that mailing list gets a new
|
||
tracking number assigned; people can then follow up on the submission by
|
||
sending email to @code{@var{NNN}@@debbugs.gnu.org}, where @var{NNN} is
|
||
the tracking number (@pxref{Sending a Patch Series}).
|
||
|
||
Please write commit logs in the ChangeLog format (@pxref{Change Logs,,,
|
||
standards, GNU Coding Standards}); you can check the commit history for
|
||
examples.
|
||
|
||
Before submitting a patch that adds or modifies a package definition,
|
||
please run through this check list:
|
||
|
||
@enumerate
|
||
@item
|
||
If the authors of the packaged software provide a cryptographic
|
||
signature for the release tarball, make an effort to verify the
|
||
authenticity of the archive. For a detached GPG signature file this
|
||
would be done with the @code{gpg --verify} command.
|
||
|
||
@item
|
||
Take some time to provide an adequate synopsis and description for the
|
||
package. @xref{Synopses and Descriptions}, for some guidelines.
|
||
|
||
@item
|
||
Run @code{guix lint @var{package}}, where @var{package} is the
|
||
name of the new or modified package, and fix any errors it reports
|
||
(@pxref{Invoking guix lint}).
|
||
|
||
@item
|
||
Make sure the package builds on your platform, using @code{guix build
|
||
@var{package}}.
|
||
|
||
@item
|
||
We recommend you also try building the package on other supported
|
||
platforms. As you may not have access to actual hardware platforms, we
|
||
recommend using the @code{qemu-binfmt-service-type} to emulate them. In
|
||
order to enable it, add the following service to the list of services in
|
||
your @code{operating-system} configuration:
|
||
|
||
@example
|
||
(service qemu-binfmt-service-type
|
||
(qemu-binfmt-configuration
|
||
(platforms (lookup-qemu-platforms "arm" "aarch64" "mips64el"))
|
||
(guix-support? #t)))
|
||
@end example
|
||
|
||
Then reconfigure your system.
|
||
|
||
You can then build packages for different platforms by specifying the
|
||
@code{--system} option. For example, to build the "hello" package for
|
||
the armhf, aarch64, or mips64 architectures, you would run the following
|
||
commands, respectively:
|
||
@example
|
||
guix build --system=armhf-linux --rounds=2 hello
|
||
guix build --system=aarch64-linux --rounds=2 hello
|
||
guix build --system=mips64el-linux --rounds=2 hello
|
||
@end example
|
||
|
||
@item
|
||
@cindex bundling
|
||
Make sure the package does not use bundled copies of software already
|
||
available as separate packages.
|
||
|
||
Sometimes, packages include copies of the source code of their
|
||
dependencies as a convenience for users. However, as a distribution, we
|
||
want to make sure that such packages end up using the copy we already
|
||
have in the distribution, if there is one. This improves resource usage
|
||
(the dependency is built and stored only once), and allows the
|
||
distribution to make transverse changes such as applying security
|
||
updates for a given software package in a single place and have them
|
||
affect the whole system---something that bundled copies prevent.
|
||
|
||
@item
|
||
Take a look at the profile reported by @command{guix size}
|
||
(@pxref{Invoking guix size}). This will allow you to notice references
|
||
to other packages unwillingly retained. It may also help determine
|
||
whether to split the package (@pxref{Packages with Multiple Outputs}),
|
||
and which optional dependencies should be used. In particular, avoid adding
|
||
@code{texlive} as a dependency: because of its extreme size, use
|
||
@code{texlive-tiny} or @code{texlive-union} instead.
|
||
|
||
@item
|
||
For important changes, check that dependent package (if applicable) are
|
||
not affected by the change; @code{guix refresh --list-dependent
|
||
@var{package}} will help you do that (@pxref{Invoking guix refresh}).
|
||
|
||
@c See <https://lists.gnu.org/archive/html/guix-devel/2016-10/msg00933.html>.
|
||
@cindex branching strategy
|
||
@cindex rebuild scheduling strategy
|
||
Depending on the number of dependent packages and thus the amount of
|
||
rebuilding induced, commits go to different branches, along these lines:
|
||
|
||
@table @asis
|
||
@item 300 dependent packages or less
|
||
@code{master} branch (non-disruptive changes).
|
||
|
||
@item between 300 and 1,200 dependent packages
|
||
@code{staging} branch (non-disruptive changes). This branch is intended
|
||
to be merged in @code{master} every 3 weeks or so. Topical changes
|
||
(e.g., an update of the GNOME stack) can instead go to a specific branch
|
||
(say, @code{gnome-updates}).
|
||
|
||
@item more than 1,200 dependent packages
|
||
@code{core-updates} branch (may include major and potentially disruptive
|
||
changes). This branch is intended to be merged in @code{master} every
|
||
2.5 months or so.
|
||
@end table
|
||
|
||
All these branches are @uref{https://hydra.gnu.org/project/gnu,
|
||
tracked by our build farm} and merged into @code{master} once
|
||
everything has been successfully built. This allows us to fix issues
|
||
before they hit users, and to reduce the window during which pre-built
|
||
binaries are not available.
|
||
|
||
Generally, branches other than @code{master} are considered
|
||
@emph{frozen} if there has been a recent evaluation, or there is a
|
||
corresponding @code{-next} branch. Please ask on the mailing list or
|
||
IRC if unsure where to place a patch.
|
||
@c TODO: It would be good with badges on the website that tracks these
|
||
@c branches. Or maybe even a status page.
|
||
|
||
@item
|
||
@cindex determinism, of build processes
|
||
@cindex reproducible builds, checking
|
||
Check whether the package's build process is deterministic. This
|
||
typically means checking whether an independent build of the package
|
||
yields the exact same result that you obtained, bit for bit.
|
||
|
||
A simple way to do that is by building the same package several times in
|
||
a row on your machine (@pxref{Invoking guix build}):
|
||
|
||
@example
|
||
guix build --rounds=2 my-package
|
||
@end example
|
||
|
||
This is enough to catch a class of common non-determinism issues, such
|
||
as timestamps or randomly-generated output in the build result.
|
||
|
||
Another option is to use @command{guix challenge} (@pxref{Invoking guix
|
||
challenge}). You may run it once the package has been committed and
|
||
built by @code{@value{SUBSTITUTE-SERVER}} to check whether it obtains the same
|
||
result as you did. Better yet: Find another machine that can build it
|
||
and run @command{guix publish}. Since the remote build machine is
|
||
likely different from yours, this can catch non-determinism issues
|
||
related to the hardware---e.g., use of different instruction set
|
||
extensions---or to the operating system kernel---e.g., reliance on
|
||
@code{uname} or @file{/proc} files.
|
||
|
||
@item
|
||
When writing documentation, please use gender-neutral wording when
|
||
referring to people, such as
|
||
@uref{https://en.wikipedia.org/wiki/Singular_they, singular
|
||
``they''@comma{} ``their''@comma{} ``them''}, and so forth.
|
||
|
||
@item
|
||
Verify that your patch contains only one set of related changes.
|
||
Bundling unrelated changes together makes reviewing harder and slower.
|
||
|
||
Examples of unrelated changes include the addition of several packages,
|
||
or a package update along with fixes to that package.
|
||
|
||
@item
|
||
Please follow our code formatting rules, possibly running the
|
||
@command{etc/indent-code.el} script to do that automatically for you
|
||
(@pxref{Formatting Code}).
|
||
|
||
@item
|
||
When possible, use mirrors in the source URL (@pxref{Invoking guix download}).
|
||
Use reliable URLs, not generated ones. For instance, GitHub archives are not
|
||
necessarily identical from one generation to the next, so in this case it's
|
||
often better to clone the repository. Don't use the @command{name} field in
|
||
the URL: it is not very useful and if the name changes, the URL will probably
|
||
be wrong.
|
||
|
||
@end enumerate
|
||
|
||
When posting a patch to the mailing list, use @samp{[PATCH] @dots{}} as
|
||
a subject. You may use your email client or the @command{git
|
||
send-email} command (@pxref{Sending a Patch Series}). We prefer to get
|
||
patches in plain text messages, either inline or as MIME attachments.
|
||
You are advised to pay attention if your email client changes anything
|
||
like line breaks or indentation which could potentially break the
|
||
patches.
|
||
|
||
When a bug is resolved, please close the thread by sending an email to
|
||
@email{@var{NNN}-done@@debbugs.gnu.org}.
|
||
|
||
@unnumberedsubsec Sending a Patch Series
|
||
@anchor{Sending a Patch Series}
|
||
@cindex patch series
|
||
@cindex @code{git send-email}
|
||
@cindex @code{git-send-email}
|
||
|
||
When sending a patch series (e.g., using @code{git send-email}), please
|
||
first send one message to @email{guix-patches@@gnu.org}, and then send
|
||
subsequent patches to @email{@var{NNN}@@debbugs.gnu.org} to make sure
|
||
they are kept together. See
|
||
@uref{https://debbugs.gnu.org/Advanced.html, the Debbugs documentation}
|
||
for more information.
|
||
@c Debbugs bug: https://debbugs.gnu.org/db/15/15361.html
|