-This file contains information on Emacs developer processes.
+* How developers contribute to GNU Emacs
-For information on contributing to Emacs as a non-developer, see
-(info "(emacs)Contributing") or
+Here is how software developers can contribute to Emacs. (Non-developers: see
http://www.gnu.org/software/emacs/manual/html_node/emacs/Contributing.html
+or run the shell command 'info "(emacs)Contributing"'.)
+
+** The Emacs repository
+
+Emacs development uses Git on Savannah for its main repository.
+Briefly, the following shell commands build and run Emacs from scratch:
+
+ git config --global user.name 'Your Name'
+ git config --global user.email 'your.name@example.com'
+ git config --global transfer.fsckObjects true
+ git clone git://git.sv.gnu.org/emacs.git
+ cd emacs
+ ./autogen.sh
+ ./configure
+ make
+ src/emacs
+
+For more details, see
+http://www.emacswiki.org/emacs/GitQuickStartForEmacsDevs and
+http://www.emacswiki.org/emacs/GitForEmacsDevs or see the file
+admin/notes/git-workflow.
+
+** Getting involved with development
+
+You can subscribe to the emacs-devel@gnu.org mailing list, paying
+attention to postings with subject lines containing "emacs-announce",
+as these discuss important events like feature freezes. See
+http://lists.gnu.org/mailman/listinfo/emacs-devel for mailing list
+instructions and archives. You can develop and commit changes in your
+own copy of the repository, and discuss proposed changes on the
+mailing list. Frequent contributors to Emacs can request write access
+there.
+
+** Committing changes by others
+
+If committing changes written by someone else, commit in their name,
+not yours. You can use 'git commit --author="AUTHOR"' to specify a
+change's author.
+
+** Commit messages
+
+Ordinarily, a change you commit should contain a log entry in its
+commit message and should not touch the repository's ChangeLog files.
+Here is an example commit message (indented):
+
+ Deactivate shifted region
+
+ Do not silently extend a region that is not highlighted;
+ this can happen after a shift (Bug#19003).
+ * doc/emacs/mark.texi (Shift Selection): Document the change.
+ * lisp/window.el (handle-select-window):
+ * src/frame.c (Fhandle_switch_frame, Fselected_frame):
+ Deactivate the mark.
+
+Occasionally, commit messages are collected and prepended to a
+ChangeLog file, where they can be corrected. It saves time to get
+them right the first time, so here are guidelines for formatting them:
+
+- Start with a single unindented summary line explaining the change;
+ do not end this line with a period. If that line starts with a
+ semicolon and a space "; ", the commit message will be ignored when
+ generating the ChangeLog file. Use this for minor commits that do
+ not need separate ChangeLog entries, such as changes in etc/NEWS.
+
+- After the summary line, there should be an empty line, then
+ unindented ChangeLog entries.
+
+- Limit lines in commit messages to 78 characters, unless they consist
+ of a single word of at most 140 characters; this is enforced by a
+ commit hook. It's nicer to limit the summary line to 50 characters;
+ this isn't enforced. If the change can't be summarized so briefly,
+ add a paragraph after the empty line and before the individual file
+ descriptions.
-* Information for Emacs Developers.
-
-An "Emacs Developer" is someone who contributes a lot of code or
-documentation to the Emacs repository. Generally, they have write
-access to the Emacs git repository on Savannah
-https://savannah.gnu.org/git/?group=emacs.
-
-** Write access to the Emacs repository.
-
-Once you become a frequent contributor to Emacs, we can consider
-giving you write access to the version-control repository. Request
-access on the emacs-devel@gnu.org mailing list.
-
-** Using the Emacs repository
-
-Emacs uses git for the source code repository.
-
-See http://www.emacswiki.org/emacs/GitQuickStartForEmacsDevs to get
-started, and http://www.emacswiki.org/emacs/GitForEmacsDevs for more
-advanced information.
+- If only a single file is changed, the summary line can be the normal
+ file first line (starting with the asterisk). Then there is no
+ individual files section.
-Alternately, see admin/notes/git-workflow.
+- If the commit has more than one author, the commit message should
+ contain separate lines to mention the other authors, like the
+ following:
-If committing changes written by someone else, make the ChangeLog
-entry in their name, not yours. git distinguishes between the author
-and the committer; use the --author option on the commit command to
-specify the actual author; the committer defaults to you.
+ Co-authored-by: Joe Schmoe <j.schmoe@example.org>
-** commit messages
+- If the commit is a tiny change that is exempt from copyright paperwork,
+ the commit message should contain a separate line like the following:
-When using git, commit messages should use ChangeLog format, with the
-following modifications:
+ Copyright-paperwork-exempt: yes
-- Add a single short line explaining the change, then an empty line,
- then unindented ChangeLog entries.
+- The commit message should contain "Bug#NNNNN" if it is related to
+ bug number NNNNN in the debbugs database. This string is often
+ parenthesized, as in "(Bug#19003)".
- You can use various Emacs functions to ease this process; see (info
- "(emacs)Change Log Commands") or
- http://www.gnu.org/software/emacs/manual/html_node/emacs/Change-Log-Commands.html.
+- Commit messages should contain only printable UTF-8 characters.
-- The summary line is limited to 72 characters (enforced by a commit
- hook). If you have trouble making that a good summary, add a
- paragraph below it, before the individual file descriptions.
+- Commit messages should not contain the "Signed-off-by:" lines that
+ are used in some other projects.
-- If only a single file is changed, the summary line can be the normal
- file first line (starting with the asterisk). Then there is no
- individual files section.
+- Any lines of the commit message that start with "; " are omitted
+ from the generated ChangeLog.
- Explaining the rationale for a design choice is best done in comments
- in the source code. However, sometimes it is useful to describe just
+ in the source code. However, sometimes it is useful to describe just
the rationale for a change; that can be done in the commit message
between the summary line and the file entries.
-** ChangeLog notes
+- Emacs generally follows the GNU coding standards for ChangeLogs: see
+ http://www.gnu.org/prep/standards/html_node/Change-Logs.html
+ or run 'info "(standards)Change Logs"'. One exception is that
+ commits still sometimes quote `like-this' (as the standards used to
+ recommend) rather than 'like-this' or ‘like this’ (as they do now),
+ as `...' is so widely used elsewhere in Emacs.
-- Emacs generally follows the GNU coding standards when it comes to
- ChangeLogs:
- http://www.gnu.org/prep/standards/html_node/Change-Logs.html . One
- exception is that we still sometimes quote `like-this' (as the
- standards used to recommend) rather than 'like-this' (as they do
- now), because `...' is so widely used elsewhere in Emacs.
+- Some commenting rules in the GNU coding standards also apply
+ to ChangeLog entries: they must be in English, and be complete
+ sentences starting with a capital and ending with a period (except
+ the summary line should not end in a period). See
+ http://www.gnu.org/prep/standards/html_node/Comments.html
+ or run 'info "(standards)Comments"'.
-- Some of the rules in the GNU coding standards section 5.2
- "Commenting Your Work" also apply to ChangeLog entries: they must be
- in English, and be complete sentences starting with a capital and
- ending with a period (except the summary line should not end in a
- period).
-
- It is tempting to relax this rule for commit messages, since they
- are somewhat transient. However, they are preserved indefinitely,
- and have a reasonable chance of being read in the future, so it's
- better that they have good presentation.
-
-- There are multiple ChangeLogs in the emacs source; roughly one per
- high-level directory. The ChangeLog entry for a commit belongs in the
- lowest ChangeLog that is higher than or at the same level as any file
- changed by the commit.
+ They are preserved indefinitely, and have a reasonable chance of
+ being read in the future, so it's better that they have good
+ presentation.
- Use the present tense; describe "what the change does", not "what
the change did".
- Preferred form for several entries with the same content:
- * help.el (view-lossage):
- * kmacro.el (kmacro-edit-lossage):
- * edmacro.el (edit-kbd-macro): Fix docstring, lossage is now 300 keys.
+ * lisp/help.el (view-lossage):
+ * lisp/kmacro.el (kmacro-edit-lossage):
+ * lisp/edmacro.el (edit-kbd-macro): Fix docstring, lossage is now 300.
(Rather than anything involving "ditto" and suchlike.)
-- If the commit fixes a bug, add a separate line
-
- Fixes: bug#NNNN
-
- where NNNN is the bug number.
-
-- In ChangeLog entries, there is no standard or recommended way to
- identify revisions.
+- There is no standard or recommended way to identify revisions in
+ ChangeLog entries. Using Git SHA1 values limits the usability of
+ the references to Git, and will become much less useful if Emacs
+ switches to a different VCS. So we recommend against that.
One way to identify revisions is by quoting their summary line.
Another is with an action stamp - an RFC3339 date followed by !
followed by the committer's email - for example,
- "2014-01-16T05:43:35Z!esr@thyrsus.com". Often, "my previous commit"
+ "2014-01-16T05:43:35Z!esr@thyrsus.com". Often, "my previous commit"
will suffice.
-- There is no need to make separate ChangeLog entries for files such
- as NEWS, MAINTAINERS, and FOR-RELEASE, or to indicate regeneration
- of files such as 'configure'. "There is no need" means you don't
- have to, but you can if you want to.
-
-** branches
-
-Development normally takes places on the trunk.
-Sometimes specialized features are developed on separate branches
-before possibly being merged to the trunk.
-
-Development is discussed on the emacs-devel mailing list.
-
-Sometime before the release of a new major version of Emacs a "feature
-freeze" is imposed on the trunk, to prepare for creating a release
-branch. No new features may be added to the trunk after this point,
-until the release branch is created. Announcements about the freeze
-(and other important events) are made on the info-gnu-emacs mailing
-list, and not anywhere else.
-
-The trunk branch is named "master" in git; release branches are named
-"emacs-nn" where "nn" is the major version.
+- There is no need to mention files such as NEWS and MAINTAINERS, or
+ to indicate regeneration of files such as 'lib/gnulib.mk', in the
+ ChangeLog entry. "There is no need" means you don't have to, but
+ you can if you want to.
+
+** Generating ChangeLog entries
+
+- You can use Emacs functions to write ChangeLog entries; see
+ http://www.gnu.org/software/emacs/manual/html_node/emacs/Change-Log-Commands.html
+ or run 'info "(emacs)Change Log Commands"'.
+
+- If you use Emacs VC, one way to format ChangeLog entries is to create
+ a top-level ChangeLog file manually, and update it with 'C-x 4 a' as
+ usual. Do not register the ChangeLog file under git; instead, use
+ 'C-c C-a' to insert its contents into into your *vc-log* buffer.
+ Or if 'log-edit-hook' includes 'log-edit-insert-changelog' (which it
+ does by default), they will be filled in for you automatically.
+
+- Alternatively, you can use the vc-dwim command to maintain commit
+ messages. When you create a source directory, run the shell command
+ 'git-changelog-symlink-init' to create a symbolic link from
+ ChangeLog to .git/c/ChangeLog. Edit this ChangeLog via its symlink
+ with Emacs commands like 'C-x 4 a', and commit the change using the
+ shell command 'vc-dwim --commit'. Type 'vc-dwim --help' for more.
+
+** Branches
+
+Future development normally takes place on the master branch.
+Sometimes specialized features are developed on other branches before
+possibly being merged to the master. Release branches are named
+"emacs-NN" where NN is the major version number, and are mainly
+intended for more-conservative changes such as bug fixes. Typically,
+collective development is active on the master branch and possibly on
+the current release branch. Periodically, the current release branch
+is merged into the master, using the gitmerge function described in
+admin/notes-git-workflow.
If you are fixing a bug that exists in the current release, be sure to
commit it to the release branch; it will be merged to the master
-branch later.
+branch later by the gitmerge function.
However, if you know that the change will be difficult to merge to the
-trunk (eg because the trunk code has changed a lot), you can apply the
-change to both trunk and branch yourself. Indicate in the release
-branch commit log that there is no need to merge the commit to the
-trunk; start the commit message with "Backport:". gitmerge.el will
-then exclude that commit from the merge to trunk.
-
+master (e.g., because the code on master has changed a lot), you can
+apply the change to both master and branch yourself. It could also
+happen that a change is cherry-picked from master to the release
+branch, and so doesn't need to be merged back. In these cases,
+say in the release branch commit message that there is no need to merge
+the commit to master, by starting the commit message with "Backport:".
+The gitmerge function excludes these commits from the merge to the master.
+
+Some changes should not be merged to master at all, for whatever
+reasons. These should be marked by including something like "Do not
+merge to master" or anything that matches gitmerge-skip-regexp (see
+admin/gitmerge.el) in the commit message.
** Other process information
-See all the files in admin/notes/* . In particular, see
-admin/notes/newfile, see admin/notes/repo.
-
-*** git vs rename
-
-git does not explicitly represent a file renaming; it uses a percent
-changed heuristic to deduce that a file was renamed. So if you are
-planning to make extensive changes to a file after renaming it (or
-moving it to another directory), you should:
-
-- create a feature branch
-
-- commit the rename without any changes
-
-- make other changes
-
-- merge the feature branch to trunk, _not_ squashing the commits into
- one. The commit message on this merge should summarize the renames
- and all the changes.
-
** Emacs Mailing lists.
Discussion about Emacs development takes place on emacs-devel@gnu.org.
Bug reports and fixes, feature requests and implementations should be
sent to bug-gnu-emacs@gnu.org, the bug/feature list. This is coupled
-to the tracker at http://debbugs.gnu.org .
+to the http://debbugs.gnu.org tracker.
+
+The Savannah info page http://savannah.gnu.org/mail/?group=emacs
+describes how to subscribe to the mailing lists, or see the list
+archives.
-You can subscribe to the mailing lists, or see the list archives,
-by following links from http://savannah.gnu.org/mail/?group=emacs .
+To email a patch you can use a shell command like 'git format-patch -1'
+to create a file, and then attach the file to your email. This nicely
+packages the patch's commit message and changes. To send just one
+such patch without additional remarks, you can use a command like
+'git send-email --to=bug-gnu-emacs@gnu.org 0001-DESCRIPTION.patch'.
-** Document your changes.
+** Issue tracker (a.k.a. "bug tracker")
+
+The Emacs issue tracker at http://debbugs.gnu.org lets you view bug
+reports and search the database for bugs matching several criteria.
+Messages posted to the bug-gnu-emacs@gnu.org mailing list, mentioned
+above, are recorded by the tracker with the corresponding bugs/issues.
+
+GNU ELPA has a 'debbugs' package that allows accessing the tracker
+database from Emacs.
+
+** Documenting your changes
Any change that matters to end-users should have an entry in etc/NEWS.
Think about whether your change requires updating the manuals. If you
know it does not, mark the NEWS entry with "---". If you know
that *all* the necessary documentation updates have been made, mark
-the entry with "+++". Otherwise do not mark it.
+the entry with "+++". Otherwise do not mark it.
+
+For more specific tips on Emacs's doc style, see
+http://www.gnu.org/software/emacs/manual/html_node/elisp/Documentation-Tips.html
+Use 'checkdoc' to check for documentation errors before submitting a patch.
+
+** Testing your changes
+
+Please test your changes before committing them or sending them to the
+list. If possible, add a new test along with any bug fix or new
+functionality you commit (of course, some changes cannot be easily
+tested).
+
+Emacs uses ERT, Emacs Lisp Regression Testing, for testing. See
+http://www.gnu.org/software/emacs/manual/html_node/ert/
+or run 'info "(ert)"' for for more information on writing and running
+tests.
+
+If your test lasts longer than some few seconds, mark it in its
+'ert-deftest' definition with ":tags '(:expensive-test)".
+
+To run tests on the entire Emacs tree, run "make check" from the
+top-level directory. Most tests are in the directory
+"test/automated". From the "test/automated" directory, run "make
+<filename>" to run the tests for <filename>.el(c). See "test/README"
+for more information.
+
+** Understanding Emacs internals
+
+The best way to understand Emacs internals is to read the code. Some
+source files, such as xdisp.c, have extensive comments describing the
+design and implementation. The following resources may also help:
-** Understanding Emacs Internals.
+http://www.gnu.org/software/emacs/manual/html_node/elisp/Tips.html
+http://www.gnu.org/software/emacs/manual/html_node/elisp/GNU-Emacs-Internals.html
-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.
+or run 'info "(elisp)Tips"' or 'info "(elisp)GNU Emacs Internals"'.
The file etc/DEBUG describes how to debug Emacs bugs.
+*** Non-ASCII characters in Emacs files
+
+If you introduce non-ASCII characters into Emacs source files, use the
+UTF-8 encoding unless it cannot do the job for some good reason.
+Although it is generally a good idea to add 'coding:' cookies to
+non-ASCII source files, cookies are not needed in UTF-8-encoded *.el
+files intended for use only with Emacs version 24.5 and later.
+
+*** Useful files in the admin/ directory
+
+See all the files in admin/notes/* . In particular, see
+admin/notes/newfile, see admin/notes/repo.
+
+The file admin/MAINTAINERS records the areas of interest of frequent
+Emacs contributors. If you are making changes in one of the files
+mentioned there, it is a good idea to consult the person who expressed
+an interest in that file, and/or get his/her feedback for the changes.
+If you are a frequent contributor and have interest in maintaining
+specific files, please record those interests in that file, so that
+others could be aware of that.
+
+*** git vs rename
+
+Git does not explicitly represent a file renaming; it uses a percent
+changed heuristic to deduce that a file was renamed. So if you are
+planning to make extensive changes to a file after renaming it (or
+moving it to another directory), you should:
+
+- Create a feature branch.
+
+- Commit the rename without any changes.
+
+- Make other changes.
+
+- Merge the feature branch to the master branch, instead of squashing
+ the commits into one. The commit message on this merge should
+ summarize the renames and all the changes.
+
\f
This file is part of GNU Emacs.
Local variables:
mode: outline
paragraph-separate: "[ \f]*$"
+coding: utf-8
end: