python - How do I correctly install dulwich to get hg-git working on Windows?

Question

I'm trying to use the hg-git Mercurial extension on Windows (Windows 7 64-bit, to be specific). I have Mercurial and Git installed. I have Python 2.5 (32-bit) installed.

I followed the instructions on http://hg-git.github.com/ to install the extension. The initial easy_install failed because it was unable to compile dulwich without Visual Studio 2003.

I installed dulwich manually by:

• git clone git://git.samba.org/jelmer/dulwich.git
• cd dulwich
• c:Python25python setup.py --pure install

Now when I run easy_install hg-git, it succeeds (since the dulwich dependency is satisfied).

In my C:UsersusernameMercurial.ini, I have:

[extensions]
hgext.bookmarks =
hggit =

When I type 'hg' at a command prompt, I see: "*** failed to import extension hggit: No module named hggit"

Looking under my c:Python25 folder, the only reference to hggit I see is Libsite-packageshg_git-0.2.1-py2.5.egg. Is this supposed to be extracted somewhere, or should it work as-is?

Since that failed, I attempted the "more involved" instructions from the hg-git page that suggested cloning git://github.com/schacon/hg-git.git and referencing the path in my Mercurial configuration. I cloned the repo, and changed my extensions file to look like:

[extensions]
hgext.bookmarks =
hggit = c:codehg-githggit

Now when I run hg, I see: *** failed to import extension hggit from c:codehg-githggit: No module named dulwich.errors.

Ok, so that tells me that it is finding hggit now, because I can see in hg-githggitgit_handler.py that it calls

from dulwich.errors import HangupException

That makes me think dulwich is not installed correctly, or not in the path.

Update:

From Python command line:

import dulwich

yields Import Error: No module named dulwich

However, under C:Python25Libsite-packages, I do have a dulwich-0.5.0-py2.5.egg folder which appears to be populated. This was created by the steps mentioned above. Is there an additional step I need to take to make it part of the Python "path"?

From Python command line (as suggested in one of the answers):

import pkg_resources
pkg_resources.require('dulwich')

yields [dulwich 0.5.0 (c:python25libsite-packagesdulwich-0.5.0-py2.5.egg)]

So what does that tell me? Importing dulwich fails, but apparently pkg_resources can find it. What can I do with that information?

Answer 1

That makes me think dulwich is not installed correctly, or not in the path.

You're absolutely right. Mercurial binary distributions for Windows are 'frozen' - they use the Python code and interpreter bundled with them and therefore independent of packages installed in system PYTHONPATH. When you specify path to hggit extension in Mercurial.ini, hg tries to import it using direct path, but dulwich library is not imported explicitly by hg and doesn't bundled with its library, so the import fails.

It is possible to add both Dulwich and HgGit into library.zip that is installed along with hg.exe, but for me the best way is to install everything from source including Mercurial and execute commands using .bat files installed into PythonScripts. In this case you will need to:

1. Install Mercurial from source. This builds "pure" version, because Windows users usually don't have Visual Studio or alternative compiler for compiling C speedups.

2. Install Dulwich - I'd use latest trunk snapshot for both Git and Dulwich.

   python setup.py --pure install

3. Install latest HgGit snapshot

   python setup.py install

4. Edit Mercurial.ini to enable hggit =

5. Launch Mercurial using your PythonScriptshg.bat