Mark J. Wielaard

When a project keeps a GNU style ChangeLog file to keep track of who changed what where then those files can be automagically merged if you use mercurial or git.

gnulib contains a module git-merge-changelog which, despite the name, works perfectly with several version control systems.

To install it:

git clone git://git.savannah.gnu.org/gnulib.git
cd gnulib
./gnulib-tool --create-testdir --dir=/tmp/testdir123 git-merge-changelog
cd /tmp/testdir123
./configure
make
make install

Mercurial

For Mercurial add the following lines to your ~/.hgrc:

[merge-patterns]
ChangeLog = git-merge-changelog

[merge-tools]
git-merge-changelog.executable = /usr/local/bin/git-merge-changelog
git-merge-changelog.args = $base $local $other

That installs the git-merge-changelog driver globally for all hg repos.

git

For git add the following lines to your ~/.gitconfig

[merge "merge-changelog"]
	name = GNU-style ChangeLog merge driver
	driver = /usr/local/bin/git-merge-changelog %O %A %B

[core]
    attributesfile = ~/.gitattributes

And add the following line to ~/.gitattributes

ChangeLog       merge=merge-changelog

Note: The global core.attributesfile exists only since git 1.7.4, before that you would have to configure this for each git repo separately, by doing:

cd ~/src/[repo-name]
echo "ChangeLog   merge=merge-changelog" >> .git/info/attributes

And never worry again about having to manually merge ChangeLog files.