Repo is primarily developed on Linux with a lot of users on macOS. Windows is, unfortunately, not a common platform. There is support in repo for Windows, but there might be some rough edges.
Keep in mind that Windows in general is "best effort" and "community supported". That means we don't actively test or verify behavior, but rely heavily on users to report problems back to us, and to contribute fixes as needed.
We only support Windows 10 or newer. This is largely due to symlinks not being available in older versions, but it's also due to most developers not using Windows.
We will never add code specific to older versions of Windows. It might work, but it most likely won't, so please don't bother asking.
*** note Warning: Repo's support for Git worktrees is new & experimental. Please report any bugs and be sure to maintain backups!
The Repo 2.4 release introduced support for Git worktrees. You don't have to worry about or understand this particular feature, so don't worry if this section of the Git manual is particularly impenetrable.
The salient point is that Git worktrees allow Repo to create repo client checkouts that do not require symlinks at all under Windows. This means users no longer need Administrator access to sync code.
Simply use --worktree when running repo init to opt in.
This does not effect specific Git repositories that use symlinks themselves.
*** note NB: This section applies to the default Repo behavior which does not use Git worktrees (see the previous section for more info).
Repo will use symlinks heavily internally. On *NIX platforms, this isn't an issue, but Windows makes it a bit difficult.
There are some documents out there for how to do this, but usually the easiest answer is to run your shell as an Administrator and invoke repo/git in that.
This isn't a great solution, but Windows doesn't make this easy, so here we are.
If you install Git Bash (see below), you can launch that with appropriate permissions so that all programs "just work".
*** note NB: This environment is only needed when running repo, or any specific git command that might involve symlinks (e.g. pull or checkout). You do not need to run all your commands in here such as your editor.
If you want to use ln -s inside of the default Git/bash shell, you might need to export this environment variable:
$ export MSYS="winsymlinks:nativestrict"
Otherwise ln -s will copy files and not actually create a symlink. This also helps tar unpack symlinks, so that's nice.
Python 3.6 or newer is required. Python 2 is known to be broken when running under Windows. See our Python Support document for more details.
You can grab the latest Windows installer here:
https://www.python.org/downloads/release/python-3
You should install the most recent version of Git for Windows:
https://git-scm.com/download/win
When installing, make sure to turn on "Enable symbolic links" when prompted.
If you've already installed Git for Windows, you can simply download the latest installer from above and run it again. It should safely upgrade things in situ for you. This is useful if you want to switch the symbolic link option after the fact.
We don't have a specific requirement for shell environments when running repo. Most developers use MinTTY/bash that's included with the Git for Windows install (so see above for installing Git).
Command & Powershell & the Windows Terminal probably work. Who knows!
When using repo upload in projects that have custom repohooks, you might get an error like the following:
$ repo upload ERROR: You must allow the pre-upload hook or use --no-verify.
This can be confusing as you never get prompted. MinTTY has a bug that breaks isatty checking inside of repo which causes repo to never interactively prompt the user which means the upload check always fails.
You can workaround this by manually granting consent when uploading. Simply add the --verify option whenever uploading:
$ repo upload --verify
You will have to specify this flag every time you upload.
When using the reference repohooks project included in AOSP, you might see errors like this when running repo upload:
$ repo upload ERROR: Traceback (most recent call last): ... File "C:\...\lib\subprocess.py", line 351, in __init__ raise ValueError("close_fds is not supported on Windows " ValueError: close_fds is not supported on Windows platforms if you redirect stdin/stderr/stdout Failed to run main() for pre-upload hook; see traceback above.
This error shows up when using Python 2. You should upgrade to Python 3 instead (see above).
If you already have Python 3 installed, make sure it's the default version. Running python --version should say Python 3, not Python 2. If you didn't install the Python versions, or don't have permission to change the default version, you can probably workaround this by changing $PATH in your shell so the Python 3 version is found first.