Ikiwiki and git

Getting ikiwiki to work correctly with git seems to be a bit of a black art. I thought I should probably document what I've discovered in the hopes of saving somebody else the trouble of figuring it out the hard way. This only covers getting the basic setup working; in particular, I don't know how to set up the CGI (so you can have a publically editable wiki, for instance), so any information specific to doing that is not included.

Make sure you have the latest version of git. Despite what its package dependencies say, ikiwiki in sid or backports depends on having a more recent git than was distributed with etch. If you don't do this, you'll get a confusing error message: fatal: Not a git repository: '.git'.
Make sure you are using two git repositories:
1. A master repository which you push directly into using git push. This repository must be a bare repository (one without a working directory).
2. A subordinate repository in which ikiwiki actually runs. This repository must contain a working directory.
A mistake I often make is not creating the master repository as a bare repository. Thankfully, this is easy to fix. Just move the master repository out of the way, create a bare clone in its place, then remove the old master:

  mv master master-tmp
  git clone --bare master-tmp master
  rm -fr master-tmp

The subordinate repository must be a clone of the master repository and not the other way around; i.e., it must have an origin branch that points at the master. If it doesn't, then either updates won't be incorporated into the subordinate branch automatically (the post-update script tries to pull from the origin branch). If the subordinate repository does not have an origin branch at all, you'll get the message fatal: 'origin': unable to chdir or not a git archive.
Make sure that the rcs option is enabled in ikiwiki.setup and set to git.
Make sure the post-update wrapper is enabled:
```
wrappers => [
  ...
  {
    wrapper => "/absolute/path/to/repository/hooks/post-update",
  },
]
```
If the path is not absolute, I seem to get errors from ikiwiki.
You have to run ikiwiki in the subordinate repository whenever you change the setup in order to create and/or update the post-update hook in the master repository.

Another tip I've found useful is to have two ikiwiki.setup files: one for previewing on my own computer and a separate one (containing all the git magic and a few changes to settings) for publishing on the Web. I've adopted the convention of calling the published setup ikiwiki-site.setup to avoid confusion.