Preamble
========

Tmux portable relies on  repositories "tmux" and "tmux-openbsd".
Here's a description of them:

* "tmux" is the portable version, the one which contains code for other
  operating systems, and autotools, etc., which isn't found or needed in the
  OpenBSD base system.

* "tmux-openbsd" is the version of tmux in OpenBSD base system which provides
  the basis of the portable tmux version.

Note:  The "tmux-openbsd" repository is actually handled by "git cvsimport"
running at 15 minute intervals, so a commit made to OpenBSD's tmux CVS
repository will take at least that long to appear in this git repository.
(It might take longer, depending on the CVS mirror used to import the
OpenBSD code).

If you've never used git before, git tracks meta-data about the committer
and the author, as part of a commit, hence:

% git config [--global] user.name "Your name"
% git config [--global] user.email "you@yourdomain.com"

Note that, if you already have this in the global ~/.gitconfig option, then
this will be used.  Setting this per-repository would involve not using the
"--global" flag above.   If you wish to use the same credentials always,
pass the "--global" option, as shown.

This is a one-off operation once the repository has been cloned, assuming
this information has ever been set before.

Cloning repositories
====================

This involves having both tmux and tmux-openbsd cloned, as in:

% cd /some/where/useful
% git clone https://github.com/tmux/tmux.git
% git clone https://github.com/ThomasAdam/tmux-openbsd.git

Note that you do not need additional checkouts to manage the sync -- an
existing clone of either repositories will suffice.  So if you already have
these checkouts existing, skip that.

Adding in git-remotes
=====================

Because the portable "tmux" git repository and the "tmux-openbsd"
repository do not inherently share any history between each other, the
history has been faked between them.  This "faking of history" is something
which has to be told to git for the purposes of comparing the "tmux" and
"tmux-openbsd" repositories for syncing.  To do this, we must reference the
clone of the "tmux-openbsd" repository from the "tmux" repository, as
shown by the following command:

% cd /path/to/tmux
% git remote add obsd-tmux file:///path/to/tmux-openbsd

So that now, the remote "obsd-tmux" can be used to reference branches and
commits from the "tmux-openbsd" repository, but from the context of the
portable "tmux" repository, which makes sense because it's the "tmux"
repository which will have the updates applied to them.

Fetching updates
================

To ensure the latest commits from "tmux-openbsd" can be found from within
"tmux", we have to ensure the "master" branch from "tmux-openbsd" is
up-to-date first, and then reference that update in "tmux", as in:

% cd /path/to/tmux-openbsd
% git checkout master
% git pull

Then back in "tmux":

% cd /path/to/tmux
% git fetch obsd-tmux

Creating the necessary branches
===============================

Now that "tmux" can see commits and branches from "tmux-openbsd" by way
of the remote name "obsd-tmux", we can now create the master branch from
"tmux-openbsd" in the "tmux" repository:

% git checkout -b obsd-master obsd-tmux/master

Adding in the fake history points
================================= 

To tie both the "master" branch from "tmux" and the "obsd-master"
branch from "tmux-openbsd" together, the fake history points added to the
"tmux" repository need to be added.  To do this, we must add an
additional refspec line, as in:

% cd /path/to/tmux
% git config --add remote.origin.fetch '+refs/replace/*:refs/replace/*'
% git fetch origin

Performing the Sync
===================

Make sure the "master" branch is checked out:

% git checkout master

The following will show commits on OpenBSD not yet synched with "tmux":

% git log master..obsd-master

From there, merge the result in, fixing up any conflicts which might arise.

% git merge obsd-master

Then ensure things look correct by BUILDING the result of that sync:

% make clean && ./autogen.sh && ./configure && make

Compare the git merge result with what's on origin/master -- that is, check
which commits you're about to push:

% git log origin/master..master

And if happy:

% git push origin master

Keeping an eye on libutil in OpenBSD
====================================

A lot of the compat/ code in tmux comes from libutil, especially imsg.
Sometimes the API can change, etc., which might cause interesting problems
trying to run the portable version of tmux.  It's worth checking
periodically for any changes to libutil in OpenBSD and syncing those files
to compat/ as and when appropriate.

Release tmux for next version
=============================

1. Update and commit README and CHANGES.  The former should be checked for
   anything outdated and updated with a list of things that might break
   upgrades and the latter should mention all the major changes since
   the last version.

2. Make sure configure.ac has the new version number.

3. Tag with:

   % git tag -a 2.X

   Where "2.X" is the next version.

   Push the tag out with:

   % git push --tags

4. Build the tarball with 'make dist'.

5. Check the tarball.  If it's good, go here to select the tag just pushed:

   https://github.com/tmux/tmux/tags

   Click the "Add release notes", upload the tarball and add a link in the
   description field to the CHANGES file.

6. Clone the tmux.github.io repository, and change the RELEASE version in the
   Makefile.  Commit it, and run 'make' to replace %%RELEASE%%.  Push the
   result out.

7. Change version back to master in configure.ac.
