Install inside MSYS2 proper

Please note that this scenario is not officially supported by Git for Windows

If you need help with the installation steps, you can contact @Elieux on the git-for-windows/git Gitter room or on the #msys2 IRC channel. Please don't file issues with Git for Windows installed this way until you verify them in an official Git for Windows distribution.

This guide assumes that you want the 64-bit version of Git for Windows.

Git for Windows being based on MSYS2, it's possible to install the mingw-w64-git package into an existing MSYS2 installation. That means that if you are already using MSYS2 on your computer, you can use Git for Windows without running the full installer or using the portable version.

Note however that there are some caveats for going this way. Git for Windows created some patches for msys2-runtime that have not been sent upstream. (This had been planned, but it was determined in issue #284 that it would probably not be happening.) This means that you have to install Git for Windows customized msys2-runtime to have a fully working git inside MSYS2.

Here the steps to take:

1. Open an MSYS2 terminal with msys2_shell.cmd.

2. Edit /etc/pacman.conf and just before [mingw32] (line #71 on my machine), add the git-for-windows packages repository:

   [git-for-windows]
   Server = https://wingit.blob.core.windows.net/x86-64 
   

   and optionally also the MINGW-only repository for the opposite architecture (i.e. MINGW32 for 64-bit SDK):

   [git-for-windows-mingw32]
   Server = https://wingit.blob.core.windows.net/i686
   

   If you are comfortable with command line and the sed command, the step 2 can be done with the following sed command (make sure to do proper backup before trying it):

   sed -i '/^\[mingw32\]/{ s|^|[git-for-windows]\nServer = https://wingit.blob.core.windows.net/x86-64\n\n|; }' /etc/pacman.conf
   

3. Authorize signing key with:

   curl -L https://raw.githubusercontent.com/git-for-windows/build-extra/HEAD/git-for-windows-keyring/git-for-windows.gpg |
   pacman-key --add - &&
   pacman-key --lsign-key 3B6D86A1BA7701CD0F23AED888138B9E1A9F3986
   

4. Then synchronize new repository with

   pacman -Syyuu
   

5. This updates msys2-runtime and therefore will ask you to close the window (not just exit the pacman process). Don't panic, simply close all currently open MSYS2 shells and MSYS2 programs. Double-check Task Manager and kill pacman.exe it's still running after the window is closed, because it can linger. Once all are closed, start a new terminal again.

   It might happen that the packages are downgrades. This is unfortunate but if you want the authentic Git for Windows experience, it's necessary.

6. Then synchronize again (updating the non-core part of the packages):

   pacman -Suu
   

7. And finally install the Git/cURL packages:

   pacman -S mingw-w64-x86_64-{git,git-doc-html,git-doc-man,curl} git-extra
   

8. Close the current shell and open a MINGW64 shell (msys2_shell.cmd -mingw64).

9. Finally, check that everything went well by doing git --version and it should output something like git version 2.14.1.windows.1 (or newer).