CONTRIBUTE   [plain text]

Copyright (C) 2006, 2007  Free Software Foundation, Inc.
See end for license conditions.

			Contributing to Emacs

Emacs is a collaborative project and we encourage contributions from
anyone and everyone.  If you want to contribute in the way that will
help us most, we recommend (1) fixing reported bugs and (2)
implementing the feature ideas in etc/TODO.  However, if you think of
new features to add, please suggest them too -- we might like your
idea.  Porting to new platforms is also useful, when there is a new
platform, but that is not common nowadays.

For documentation on how to develop Emacs changes, refer to the Emacs
Manual and the Emacs Lisp Reference Manual (both included in the Emacs
distribution).  The web pages in
contain additional information.

You may also want to submit your change so that can be considered for
inclusion in a future version of Emacs (see below).

If you don't feel up to hacking Emacs, there are many other ways to
help.  You can answer questions on the mailing lists, write
documentation, find and report bugs, contribute to the Emacs web
pages, or develop a package that works with Emacs.

Here are some style and legal conventions for contributors to Emacs:

* Coding Standards

Contributed code should follow the GNU Coding Standard.

If it doesn't, we'll need to find someone to fix the code before we
can use it.

Emacs has certain additional style and coding conventions.

Ref: GNU Coding Standards Info Manual
Ref: The "Tips" Appendix in the Emacs Lisp Reference.

* Copyright Assignment

We can accept small changes without legal papers, and for medium-size
changes a copyright disclaimer is ok too.  To accept substantial
contributions from you, we need a copyright assignment form filled out
and filed with the FSF.

Contact us at to obtain the relevant forms.

* Getting the Source Code

The latest version of Emacs can be downloaded using CVS or Arch from
the Savannah web site.  It is important to write your patch based on
this version; if you start from an older version, your patch may be
outdated when you write it, and maintainers will have hard time
applying it.

After you have downloaded the CVS source, you should read the file
INSTALL.CVS for build instructions (they differ to some extent from a
normal build).


* Submitting Patches

Every patch must have several pieces of information before we
can properly evaluate it.

When you have all these pieces, bundle them up in a mail message and
send it to or

All subsequent discussion should also be sent to the mailing list.

** Description

For bug fixes, a description of the bug and how your patch fixes this

For new features, a description of the feature and your

** ChangeLog

A ChangeLog entry as plaintext (separate from the patch).

See the various ChangeLog files for format and content. Note that,
unlike some other projects, we do require ChangeLogs also for
documentation, i.e. Texinfo files.

Ref: "Change Log Concepts" node of the GNU Coding Standards Info
Manual, for how to write good log entries.

** The patch itself.

Please use "Context Diff" format.

If you are accessing the CVS repository use
	cvs update; cvs diff -cp
else, use
	diff -cp OLD NEW

If your version of diff does not support these options, then get the
latest version of GNU Diff.

** Mail format.

We prefer to get the patches as inline plain text.

Please be aware of line wrapping which will make the patch unreadable
and useless for us.  To avoid that, you can use MIME attachments or,
as a last resort, uuencoded gzipped text.

** Please reread your patch before submitting it.

** Do not mix changes.

If you send several unrelated changes together, we will ask you to
separate them so we can consider each of the changes by itself.

* Coding style and conventions.

** Mandatory reading:

The "Tips and Conventions" Appendix of the Emacs Lisp Reference.

** Avoid using `defadvice' or `eval-after-load' for Lisp code to be
included in Emacs.

** Remove all trailing whitespace in all source and text files.

** Use ?\s instead of ?  in Lisp code for a space character.

* Supplemental information for Emacs Developers.

** Write access to Emacs' CVS repository.

Once you become a frequent contributor to Emacs, we can consider
giving you write access to the CVS repository.

** Emacs Mailing lists.

Discussion about Emacs development takes place on

Bug reports for released versions are sent to

Bug reports for development versions are sent to

You can subscribe to the mailing lists at

You can find the mailing lists archives at or

** Document your changes.

Think carefully about whether your change requires updating the
documentation.  If it does, you can either do this yourself or add an
item to the NEWS file.

If you document your change in NEWS, please mark the NEWS entry with
the documentation status of the change: if you submit the changes for
the manuals, mark it with "+++"; if it doesn't need to be documented,
mark it with "---"; if it needs to be documented, but you didn't
submit documentation changes, leave the NEWS entry unmarked.  (These
marks are checked by the Emacs maintainers to make sure every change
was reflected in the manuals.)

** Understanding Emacs Internals.

The best way to understand Emacs Internals is to read the code,
but the nodes "Tips" and "GNU Emacs Internals" in the Appendix
of the Emacs Lisp Reference Manual may also help.

The file etc/DEBUG describes how to debug Emacs bugs.

* How to Maintain Copyright Years for GNU Emacs

See admin/notes/copyright.

** Our lawyer says it is ok if we add, to each file that has been in Emacs
since Emacs 21 came out in 2001, all the subsequent years.  We don't
need to check whether *that file* was changed in those years.
It's sufficient that *Emacs* was changed in those years (and it was!).

** For those files that have been added since then, we should add
the year it was added to Emacs, and all subsequent years.

** For the refcards under etc/, it's ok to simply use the latest year
(typically in a `\def\year{YEAR}' expression) for the rendered copyright
notice, while maintaining the full list of years in the copyright notice
in the comments.

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
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