[PATCH 1/2] Documentation: explain how safe.directory works when running under sudo

["Carlo Marcelo Arenas Belón" <carenas@gmail.com>]

In a previous patch, the behaviour of git was changed so it will be able
to find the "effective uid" that is required when git was invoked with
sudo to root, for example:

  $ sudo make install

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
---
 Documentation/config/safe.txt | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/config/safe.txt b/Documentation/config/safe.txt
index 6d764fe0ccf..67f8ef5d766 100644
--- a/Documentation/config/safe.txt
+++ b/Documentation/config/safe.txt
@@ -26,3 +26,11 @@ directory was listed in the `safe.directory` list. If `safe.directory=*`
 is set in system config and you want to re-enable this protection, then
 initialize your list with an empty value before listing the repositories
 that you deem safe.
++
+When git tries to check for ownership of git repositories it will obviously
+use the user that is being used to run git itself, but if git is running
+as root, it will first check if it might had been started through `sudo`,
+and if that is the case, will use the user id that invoked sudo instead.
+If that is not what you would prefer and want git to instead only trust
+repositories that are owned by root, then you should remove the `SUDO_UID`
+variable from root's environment.
-- 
2.36.0.266.g59f845bde02