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: