How to Build Mercurial on Windows

This how-to is intended to give some hints about how to build Mercurial on Windows from the Mercurial sources. If you don't intend to fiddle with the sources, then simply use a pre-built binary package for Windows (for example TortoiseHg, or http://mercurial.berkwood.com/, see Download). If you want to build an installer or Py2exe distribution, see BuildingWindowsInstaller.

Mercurial is mostly programmed in Python (http://www.python.org/). The Python sources don't need a compilation step, but a few Mercurial modules are programmed in C: base85.c, bdiff.c, diffhelpers.c, mpatch.c and osutil.c (http://selenic.com/repo/hg/file/tip/mercurial/). These must be compiled with a C-compiler.

The steps below worked on a Windows XP SP2, that had a Microsoft Visual C++ installed, and on Windows XP SP2, with mingw installed.

• The bug tracker entry "windows installation requires MS C compiler" at http://www.selenic.com/mercurial/bts/issue1109 has some hints about using the free mingw port of the gcc compiler instead.

Install Python 2.5, available from http://www.python.org/download/windows/

Default install path is C:\Python25. Best leave it at that.

Get the Mercurial sources (assuming you already have a working "hg" installed, see for example http://mercurial.berkwood.com/)

>cd C:\tmp\repos
>hg clone http://selenic.com/repo/hg mercurial

See DeveloperRepos for other common repositories (the most other interesting one is the CrewRepository).

Mercurial uses the "Python Distribution Utilities (Distutils)" install process, which also covers building of the extension modules (the files written in C-Code). See http://docs.python.org/inst/inst.html in the Python docs at http://docs.python.org/index.html.

The first step is doing a python setup.py build at the top level directory of the Mercurial package. If using mingw, a setup.cfg needs to be created which directs setuptools to use it:

cd mercurial
echo [build] > setup.cfg
echo compiler=mingw32 >> setup.cfg

For mingw32 using python built using Microsoft Visual Studio (If you have downloaded python installer from main python site or activestate, they are built using MS Visual Studio), you need to create an import library (archive file) for the GCC (Mingw32) toolset:

• Make sure you read the instructions on creating a GCC compatible import archive from a MSVC built DLL

• Download the prerequisites "pexports" and "dlltool" and make sure they are in the PATH
• Assuming the python interpreter is installed under "c:\python" and you are using python 2.6 (if different, change accordingly)

>cd c:\python\libs
>pexports c:\windows\system32\python26.dll > python26.def
>dlltool -C -d python26.def -l libpython26.a
>nm libpython26.a

• The last command "nm" should show you the exported symbols with "I" (as import symbol)
• If for some reason the above step does not work when you try to build "hg" (undefined symbol error due to extra "_"), try editing the "python26.def" file and remove the string "DATA" and rerun the "dlltool"

>cd mercurial
>python setup.py build
running build
running build_py
creating build
creating build\lib.win32-2.5
creating build\lib.win32-2.5\mercurial
copying mercurial\ancestor.py -> build\lib.win32-2.5\mercurial
copying mercurial\archival.py -> build\lib.win32-2.5\mercurial
copying mercurial\bundlerepo.py -> build\lib.win32-2.5\mercurial
...
building 'mercurial.mpatch' extension
creating build\temp.win32-2.5
creating build\temp.win32-2.5\Release
creating build\temp.win32-2.5\Release\mercurial
C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\bin\cl.exe /c /nologo /Ox /MD /W3 /GX /DNDEBUG -IC:\Python25\include -IC:\Python25\PC /Tcmercurial/mpatch.c /Fobuild\temp.win32-2.5\Release\mercurial/mpatch.obj mpatch.c
C:\Program Files\Microsoft Visual Studio .NET 2003\Vc7\bin\link.exe /DLL /nologo /INCREMENTAL:NO /LIBPATH:C:\Python25\libs /LIBPATH:C:\Python25\PCBuild /EXPORT:initmpatch build\temp.win32-2.5\Release\mercurial/mpatch.obj /OUT:build\lib.win32-2.5\mercurial\mpatch.pyd /IMPLIB:build\temp.win32-2.5\Release\mercurial\mpatch.lib
   Creating library build\temp.win32-2.5\Release\mercurial\mpatch.lib and object build\temp.win32-2.5\Release\mercurial\mpatch.exp
...
running build_scripts
creating build\scripts-2.5
copying and adjusting hg -> build\scripts-2.5

In the above example, Python found and used an installed Microsoft C compiler. The C-source files are compiled and linked into windows dll files using the file extension ".pyd". If the above step fails, you can find some additional tips in WindowsInstall. See also "Extending and Embedding the Python Interpreter" and the more specific "Building C and C++ Extensions on Windows" in the Python docs.

Global install

Execute python setup.py install

> python setup.py install
running install
running build
running build_py
running build_ext
running build_scripts
running install_lib
copying build\lib.win32-2.5\hgext\acl.py -> C:\Python25\Lib\site-packages\hgext
...
copying build\lib.win32-2.5\mercurial\ancestor.py -> C:\Python25\Lib\site-packages\mercurial
...
byte-compiling C:\Python25\Lib\site-packages\hgext\acl.py to acl.pyc
...
byte-compiling C:\Python25\Lib\site-packages\mercurial\ancestor.py to ancestor.pyc
...
running install_scripts
copying build\scripts-2.5\hg -> C:\Python25\Scripts
running install_data
creating C:\Python25\Lib\site-packages\mercurial\templates
copying templates\changelog.tmpl -> C:\Python25\Lib\site-packages\mercurial\templates
copying templates\changelogentry.tmpl -> C:\Python25\Lib\site-packages\mercurial\templates
...
running install_egg_info
Writing C:\Python25\Lib\site-packages\mercurial-fb259a3572e9-py2.5.egg-info

This installs hg in C:\Python25\Scripts:

> python C:\Python25\Scripts\hg version
Mercurial Distributed SCM (version fb259a3572e9)

Copyright (C) 2005-2008 Matt Mackall <mpm@selenic.com> and others
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Local install for testing/development

If you want to have a locally ready to run Mercurial (for example for testing your patches, etc.), you can use the following batch file (named it "build-win32-2.5.cmd"):

del mercurial\*.pyd
rd /S /Q build
python setup.py build
copy build\lib.win32-2.5\mercurial\*.pyd mercurial

Run it from the working directory of your cloned repo. This will copy the compiled C modules (the *.pyd files) into the mercurial directory, giving you a ready to run local hg command.

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