* Makefile.am (assert-binaries-available): Don't mention hydra.gnu.org in comment. * build-aux/check-available-binaries.scm: Likewise. * build-aux/check-final-inputs-self-contained.scm: Likewise. * doc/guix.texi (SUBSTITUTE-SERVER): New variable. Use it throughout instead of "mirror.hydra.gnu.org". * doc/contributing.texi (Submitting Patches): Likewise. * gnu/services/base.scm (hydra-key-authorization) (guix-activation): Remove mentions of "hydra.gnu.org" in comments and messages. * gnu/system/install.scm (%installation-services): Likewise. * guix/scripts/size.scm (guix-size): Likewise.
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506 lines
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@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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* 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}.
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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 Coding Style
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@section Coding Style
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In general our code follows the GNU Coding Standards (@pxref{Top,,,
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standards, GNU Coding Standards}). However, they do not say much about
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Scheme, so here are some additional rules.
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@menu
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* Programming Paradigm:: How to compose your elements.
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* Modules:: Where to store your code?
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* Data Types and Pattern Matching:: Implementing data structures.
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* Formatting Code:: Writing conventions.
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@end menu
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@node Programming Paradigm
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@subsection Programming Paradigm
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Scheme code in Guix is written in a purely functional style. One
|
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exception is code that involves input/output, and procedures that
|
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implement low-level concepts, such as the @code{memoize} procedure.
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@node Modules
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@subsection Modules
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||
|
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Guile modules that are meant to be used on the builder side must live in
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the @code{(guix build @dots{})} name space. They must not refer to
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other Guix or GNU modules. However, it is OK for a ``host-side'' module
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to use a build-side module.
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Modules that deal with the broader GNU system should be in the
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@code{(gnu @dots{})} name space rather than @code{(guix @dots{})}.
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||
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@node Data Types and Pattern Matching
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||
@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,
|
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notably the fact that it is hard to read, error-prone, and a hindrance
|
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to proper type error reports.
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||
|
||
Guix code should define appropriate data types (for instance, using
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@code{define-record-type*}) rather than abuse lists. In addition, it
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should use pattern matching, via Guile’s @code{(ice-9 match)} module,
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||
especially when matching lists.
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||
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||
@node Formatting Code
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||
@subsection Formatting Code
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||
|
||
@cindex formatting code
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||
@cindex coding style
|
||
When writing Scheme code, we follow common wisdom among Scheme
|
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programmers. In general, we follow the
|
||
@url{http://mumble.net/~campbell/scheme/style.txt, Riastradh's Lisp
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||
Style Rules}. This document happens to describe the conventions mostly
|
||
used in Guile’s code too. It is very thoughtful and well written, so
|
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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
|
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@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
|
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Emacs-Guix Reference Manual}).
|
||
|
||
@cindex indentation, of code
|
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@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
|
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@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
|
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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
|
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@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
|
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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
|
||
@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.
|
||
|
||
@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
|