HACKING - automake - Git at Google

 ================================================================
 = This file

 * This file attempts to describe the rules to use when hacking
   automake.

 ================================================================
 = Administrivia

 * The correct response to most actual bugs is to write a new test case
   which demonstrates the bug.  Then fix the bug, re-run the test suite,
   and check everything in.

 * If you incorporate a change from somebody on the net:
   First, if it is a large change, you must make sure they have signed the
   appropriate paperwork.
   Second, be sure to add their name and email address to THANKS

 * If a change fixes a test, mention the test in the commit message.
   If a change fixes a bug registered in the Automake debbugs tracker,
   mention the bug number in the commit message.

 * If somebody reports a new bug, mention his name in the commit message
   and in the test case you write.  Put him into THANKS.

 * When documenting a non-trivial idiom or example in the manual, be
   sure to add a test case for it, and to reference such test case from
   a proper Texinfo comment.

 * Some files in the automake package are not owned by automake; these
   files are listed in the $(FETCHFILES) variable in Makefile.am.  They
   should never be edited here.  Almost all of them can be updated from
   respective upstreams with "make fetch" (this should be done especially
   before releases).  The only exception is the 'lib/COPYING' (from FSF),
   which should be updated by hand whenever the GPL gets updated (which
   shouldn't happen that often anyway :-)

 * Changes other than bug fixes must be mentioned in NEWS.  Important
   bug fixes should be mentioned in NEWS, too.

 ================================================================
 = Naming

 * Internal make variables and functions should be named following patterns
   like 'am.tty-colors' or 'am.dist.files'.

 * Internal AC_SUBSTs should be named with a leading 'am__'.

 * Private make targets should be named with a leading 'am--'.

 * WARNING! This convention, introduced recently (since July 2012),
   isn't yet universally used.  But all new code should use it,
   except in those situation where that would cause spurious
   conflicts with mainline Automake.

 ================================================================
 = Editing '.am' files

 * Always use $(...) and not ${...}

 * Use ':', not 'true'.  Use 'exit 1', not 'false'.

 * Use '##' comments liberally.  Comment anything even remotely
   unusual.

 * Never use basename or dirname.  Instead use sed.

 * For install and uninstall rules, if a loop is required, it should be
   silent.  Then the body of the loop itself should print each
   "important" command it runs.  The printed commands should be preceded
   by a single space.

 * Ensure install rules do not create any installation directory where
   nothing is to be actually installed.  See automake bug#11030.

 ================================================================
 = Editing automake.in and aclocal.in

 * Indent using GNU style.  For historical reasons, the perl code
   contains portions indented using Larry Wall's style (perl-mode's
   default), and other portions using the GNU style (cperl-mode's
   default).  Write new code using GNU style.

 * Don't use & for function calls, unless required.
   The use of & prevents prototypes from being checked.
   Just as above, don't change massively all the code to strip the
   &, just convert the old code as you work on it, and write new
   code without.

 ================================================================
 = Working with git

 * To regenerate dependent files created by aclocal and automake,
   use the 'bootstrap.sh' script.  It uses the code from the source
   tree, so the resulting files (aclocal.m4 and Makefile.in) should
   be the same as you would get if you install this version of
   automake and use it to generate those files.  Be sure to have the
   latest stable version of Autoconf installed and available early
   in your PATH.

 * The Automake git tree currently carries two basic branches: 'master' for
   the current development, and 'maint' for maintenance and bug fixes.  The
   maint branch should be kept regularly merged into the master branch.
   It is advisable to merge only after a set of related commits have been
   applied, to avoid introducing too much noise in the history.

 * There may be a number of longer-lived feature branches for new
   developments.  They should be based off of a common ancestor of all
   active branches to which the feature should or might be merged later.
   in the future, we might introduce a special branch named 'next' that
   may serve as common ground for feature merging and testing, should
   they not yet be ready for master.

 * After a major release is done, the master branch is to be merged into
   the maint branch, and then a "new" master branch created stemming
   from the resulting commit.

 * When fixing a bug (especially a long-standing one), it may be useful
   to commit the fix to a new temporary branch based off the commit that
   introduced the bug.  Then this "bugfix branch" can be merged into all
   the active branches descending from the buggy commit.  This offers a
   simple way to fix the bug consistently and effectively.

 * For merges from branches other than maint, prefer 'git merge --log' over
   plain 'git merge', so that a later 'git log' gives an indication of which
   actual patches were merged even when they don't appear early in the list.

 * master and release branches should not be rewound, i.e., should always
   fast-forward, except maybe for privacy issues.  The maint branch should not
   be rewound except maybe after retiring a release branch or a new stable
   release.  For next, and for feature branches, the announcement for the
   branch should document rewinding policy.

 ================================================================
 = Writing a good commit message

 * Here is the general format that Automake's commit messages are expected
   to follow.  See the further points below for clarifications and minor
   corrections.

       topic: brief description (this is the "summary line")

       <reference to relevant bugs, if any>

       Here goes a more detailed explanation of why the commit is needed,
       and a general overview of what it does, and how.  This section is
       optional, but you are expected to provide it more often than not.

       And if the detailed explanation is quite long or detailed, you can
       want to break it in more paragraphs.

       Then you can add references to relevant mailing list discussions
       (if any), with proper links.  But don't take this as an excuse for
       writing incomplete commit messages!  The "distilled" conclusions
       reached in such discussions should have been placed in the
       paragraphs above.

       Finally, here you can thank people that motivated or helped the
       change.  So, thanks to John Doe for bringing up the issue, and to
       J. Random Hacker for providing suggestions and testing the patch.

       <detailed list of touched files>

 * The <detailed list of touched files> is mandatory but for the most
   trivial changes, and should follows the GNU guidelines for ChangeLog
   entries (described explicitly in the GNU Coding Standards); it might
   be something of this sort:

     * some/file (func1): Improved frobnication.
     (func2): Adjusted accordingly.
     * another/file (foo, bar): Likewise.
     * tests/foo.tap: New test.
     * tests/Makefile.am (TESTS): Add it.

 * If your commit fixes an automake bug registered in the tracker (say
   numbered 1234), you should put the following line after the summary
   line:

       This change fixes automake bug#1234.

 * If your commit is just related to the given bug report, but does not
   fix it, you might want to add a line like this instead:

       This change is related to automake bug#1234.

 * When referring to older commits, use 'git describe' output as pointer.
   But also try to identify the given commit by date and/or summary line
   if possible.  Examples:

       Since yesterday's commit, v1.11-2019-g4d2bf42, ...

       ... removed in commit 'v1.11-1674-g02e9072' of 01-01-2012,
       "dist: ditch support for lzma"...

 ================================================================
 = Test suite

 * Use "make check" and "make maintainer-check" liberally.

 * Make sure each test file is executable.

 * Export the 'keep_testdirs' environment variable to "yes" to keep
   test directories for successful tests also.

 * Use perl coverage information to ensure your new code is thoroughly
   tested by your new tests.

 * See file 't/README' for more information.

 ================================================================
 = Release procedure

 * The steps outlined here are meant to be followed for alpha and stable
   releases as well.  Where differences are expected, they will be
   explicitly described.

 * Fetch new versions of the files that are maintained by the FSF by
   running "make fetch".  In case any file in the automake repository
   has been updated, commit and re-run the testsuite.

 * Ensure that the copyright notices of the distributed files is up to
   date.  The maintainer-only target "update-copyright" can help with
   this.

 * Update NEWS.

 * Update the version number in configure.ac.
   (The idea is that every other alpha number will be a net release.
   The repository will always have its own "odd" number so we can easily
   distinguish net and repo versions.)

 * Run this:
   ./bootstrap.sh && ./configure && make && make check && make distcheck

 * Run "make git-tag-release".
   This will run the maintainer checks, verify that the local git
   repository and working tree are clean and up-to-date, and create
   a proper signed git tag for the release (based on the contents
   of $(VERSION)).

 * Run "make git-upload-release".
   This will first verify that you are releasing from a tagged version
   and that the local git repository and working tree are clean and
   up-to-date, and will then run "make dist" to create the tarballs,
   and invoke the 'gnupload' script sign and upload them to the correct
   locations.  In case you need to sign with a non-default key, you can
   use "make GNUPLOADFLAGS='--user KEY' git-upload-release".

 * Update version number in configure.ac to next alpha number.
   Re-run ./bootstrap.sh and commit.

 * Don't forget to "git push" your changes so they appear in the public
   git tree.

 * For stable releases, update the manuals at www.gnu.org:
   - Generate manuals:
     cd doc
     wget "http://savannah.gnu.org/cgi-bin/viewcvs/~checkout~/texinfo/texinfo/util/gendocs.sh"
     wget "http://savannah.gnu.org/cgi-bin/viewcvs/~checkout~/texinfo/texinfo/util/gendocs_template"
     sh ./gendocs.sh --email bug-automake@gnu.org automake "GNU Automake"
   - copy manuals recursively to web cvs,
   - commit.
   - Check for link errors, fix them, recheck until convergence:
     <http://validator.w3.org/checklink>

 * Send the announcement at least to <autotools-announce@gnu.org> and
   <automake@gnu.org>.  If the release is a stable one, the announcement
   must also go to <info-gnu@gnu.org>; if it is an alpha or beta release,
   announcement should be sent also to <platform-testers@gnu.org>, to
   maximize the possibility of early testing on exotic or proprietary
   systems.  Finally, copy the announcement into the NEWS feed at
   <https://savannah.gnu.org/projects/automake>.

 -----

 Copyright (C) 2003-2012 Free Software Foundation, Inc.

 This program 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.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.

 Local Variables:
 mode: text
 End:
	================================================================
	= This file

	* This file attempts to describe the rules to use when hacking
	automake.

	================================================================
	= Administrivia

	* The correct response to most actual bugs is to write a new test case
	which demonstrates the bug. Then fix the bug, re-run the test suite,
	and check everything in.

	* If you incorporate a change from somebody on the net:
	First, if it is a large change, you must make sure they have signed the
	appropriate paperwork.
	Second, be sure to add their name and email address to THANKS

	* If a change fixes a test, mention the test in the commit message.
	If a change fixes a bug registered in the Automake debbugs tracker,
	mention the bug number in the commit message.

	* If somebody reports a new bug, mention his name in the commit message
	and in the test case you write. Put him into THANKS.

	* When documenting a non-trivial idiom or example in the manual, be
	sure to add a test case for it, and to reference such test case from
	a proper Texinfo comment.

	* Some files in the automake package are not owned by automake; these
	files are listed in the $(FETCHFILES) variable in Makefile.am. They
	should never be edited here. Almost all of them can be updated from
	respective upstreams with "make fetch" (this should be done especially
	before releases). The only exception is the 'lib/COPYING' (from FSF),
	which should be updated by hand whenever the GPL gets updated (which
	shouldn't happen that often anyway :-)

	* Changes other than bug fixes must be mentioned in NEWS. Important
	bug fixes should be mentioned in NEWS, too.

	================================================================
	= Naming

	* Internal make variables and functions should be named following patterns
	like 'am.tty-colors' or 'am.dist.files'.

	* Internal AC_SUBSTs should be named with a leading 'am__'.

	* Private make targets should be named with a leading 'am--'.

	* WARNING! This convention, introduced recently (since July 2012),
	isn't yet universally used. But all new code should use it,
	except in those situation where that would cause spurious
	conflicts with mainline Automake.

	================================================================
	= Editing '.am' files

	* Always use $(...) and not ${...}

	* Use ':', not 'true'. Use 'exit 1', not 'false'.

	* Use '##' comments liberally. Comment anything even remotely
	unusual.

	* Never use basename or dirname. Instead use sed.

	* For install and uninstall rules, if a loop is required, it should be
	silent. Then the body of the loop itself should print each
	"important" command it runs. The printed commands should be preceded
	by a single space.

	* Ensure install rules do not create any installation directory where
	nothing is to be actually installed. See automake bug#11030.

	================================================================
	= Editing automake.in and aclocal.in

	* Indent using GNU style. For historical reasons, the perl code
	contains portions indented using Larry Wall's style (perl-mode's
	default), and other portions using the GNU style (cperl-mode's
	default). Write new code using GNU style.

	* Don't use & for function calls, unless required.
	The use of & prevents prototypes from being checked.
	Just as above, don't change massively all the code to strip the
	&, just convert the old code as you work on it, and write new
	code without.

	================================================================
	= Working with git

	* To regenerate dependent files created by aclocal and automake,
	use the 'bootstrap.sh' script. It uses the code from the source
	tree, so the resulting files (aclocal.m4 and Makefile.in) should
	be the same as you would get if you install this version of
	automake and use it to generate those files. Be sure to have the
	latest stable version of Autoconf installed and available early
	in your PATH.

	* The Automake git tree currently carries two basic branches: 'master' for
	the current development, and 'maint' for maintenance and bug fixes. The
	maint branch should be kept regularly merged into the master branch.
	It is advisable to merge only after a set of related commits have been
	applied, to avoid introducing too much noise in the history.

	* There may be a number of longer-lived feature branches for new
	developments. They should be based off of a common ancestor of all
	active branches to which the feature should or might be merged later.
	in the future, we might introduce a special branch named 'next' that
	may serve as common ground for feature merging and testing, should
	they not yet be ready for master.

	* After a major release is done, the master branch is to be merged into
	the maint branch, and then a "new" master branch created stemming
	from the resulting commit.

	* When fixing a bug (especially a long-standing one), it may be useful
	to commit the fix to a new temporary branch based off the commit that
	introduced the bug. Then this "bugfix branch" can be merged into all
	the active branches descending from the buggy commit. This offers a
	simple way to fix the bug consistently and effectively.

	* For merges from branches other than maint, prefer 'git merge --log' over
	plain 'git merge', so that a later 'git log' gives an indication of which
	actual patches were merged even when they don't appear early in the list.

	* master and release branches should not be rewound, i.e., should always
	fast-forward, except maybe for privacy issues. The maint branch should not
	be rewound except maybe after retiring a release branch or a new stable
	release. For next, and for feature branches, the announcement for the
	branch should document rewinding policy.

	================================================================
	= Writing a good commit message

	* Here is the general format that Automake's commit messages are expected
	to follow. See the further points below for clarifications and minor
	corrections.

	topic: brief description (this is the "summary line")

	<reference to relevant bugs, if any>

	Here goes a more detailed explanation of why the commit is needed,
	and a general overview of what it does, and how. This section is
	optional, but you are expected to provide it more often than not.

	And if the detailed explanation is quite long or detailed, you can
	want to break it in more paragraphs.

	Then you can add references to relevant mailing list discussions
	(if any), with proper links. But don't take this as an excuse for
	writing incomplete commit messages! The "distilled" conclusions
	reached in such discussions should have been placed in the
	paragraphs above.

	Finally, here you can thank people that motivated or helped the
	change. So, thanks to John Doe for bringing up the issue, and to
	J. Random Hacker for providing suggestions and testing the patch.

	<detailed list of touched files>

	* The <detailed list of touched files> is mandatory but for the most
	trivial changes, and should follows the GNU guidelines for ChangeLog
	entries (described explicitly in the GNU Coding Standards); it might
	be something of this sort:

	* some/file (func1): Improved frobnication.
	(func2): Adjusted accordingly.
	* another/file (foo, bar): Likewise.
	* tests/foo.tap: New test.
	* tests/Makefile.am (TESTS): Add it.

	* If your commit fixes an automake bug registered in the tracker (say
	numbered 1234), you should put the following line after the summary
	line:

	This change fixes automake bug#1234.

	* If your commit is just related to the given bug report, but does not
	fix it, you might want to add a line like this instead:

	This change is related to automake bug#1234.

	* When referring to older commits, use 'git describe' output as pointer.
	But also try to identify the given commit by date and/or summary line
	if possible. Examples:

	Since yesterday's commit, v1.11-2019-g4d2bf42, ...

	... removed in commit 'v1.11-1674-g02e9072' of 01-01-2012,
	"dist: ditch support for lzma"...

	================================================================
	= Test suite

	* Use "make check" and "make maintainer-check" liberally.

	* Make sure each test file is executable.

	* Export the 'keep_testdirs' environment variable to "yes" to keep
	test directories for successful tests also.

	* Use perl coverage information to ensure your new code is thoroughly
	tested by your new tests.

	* See file 't/README' for more information.

	================================================================
	= Release procedure

	* The steps outlined here are meant to be followed for alpha and stable
	releases as well. Where differences are expected, they will be
	explicitly described.

	* Fetch new versions of the files that are maintained by the FSF by
	running "make fetch". In case any file in the automake repository
	has been updated, commit and re-run the testsuite.

	* Ensure that the copyright notices of the distributed files is up to
	date. The maintainer-only target "update-copyright" can help with
	this.

	* Update NEWS.

	* Update the version number in configure.ac.
	(The idea is that every other alpha number will be a net release.
	The repository will always have its own "odd" number so we can easily
	distinguish net and repo versions.)

	* Run this:
	./bootstrap.sh && ./configure && make && make check && make distcheck

	* Run "make git-tag-release".
	This will run the maintainer checks, verify that the local git
	repository and working tree are clean and up-to-date, and create
	a proper signed git tag for the release (based on the contents
	of $(VERSION)).

	* Run "make git-upload-release".
	This will first verify that you are releasing from a tagged version
	and that the local git repository and working tree are clean and
	up-to-date, and will then run "make dist" to create the tarballs,
	and invoke the 'gnupload' script sign and upload them to the correct
	locations. In case you need to sign with a non-default key, you can
	use "make GNUPLOADFLAGS='--user KEY' git-upload-release".

	* Update version number in configure.ac to next alpha number.
	Re-run ./bootstrap.sh and commit.

	* Don't forget to "git push" your changes so they appear in the public
	git tree.

	* For stable releases, update the manuals at www.gnu.org:
	- Generate manuals:
	cd doc
	wget "http://savannah.gnu.org/cgi-bin/viewcvs/~checkout~/texinfo/texinfo/util/gendocs.sh"
	wget "http://savannah.gnu.org/cgi-bin/viewcvs/~checkout~/texinfo/texinfo/util/gendocs_template"
	sh ./gendocs.sh --email bug-automake@gnu.org automake "GNU Automake"
	- copy manuals recursively to web cvs,
	- commit.
	- Check for link errors, fix them, recheck until convergence:
	<http://validator.w3.org/checklink>

	* Send the announcement at least to <autotools-announce@gnu.org> and
	<automake@gnu.org>. If the release is a stable one, the announcement
	must also go to <info-gnu@gnu.org>; if it is an alpha or beta release,
	announcement should be sent also to <platform-testers@gnu.org>, to
	maximize the possibility of early testing on exotic or proprietary
	systems. Finally, copy the announcement into the NEWS feed at
	<https://savannah.gnu.org/projects/automake>.

	-----

	Copyright (C) 2003-2012 Free Software Foundation, Inc.

	This program 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.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>.

	Local Variables:
	mode: text
	End: