Starting with macOS 10.15 (Catalina), Apple introduced a new feature
called 'firmlinks' in order to separate the boot volume into two
volumes, one read-only and one writable but still present them to the
user as a single volume. Along with this change, Apple removed the
ability to create symlinks in the root directory and replaced them with
'synthetic firmlinks'. See 'man synthetic.conf'
When FSEevents reports the path of changed files, if the path involves
a synthetic firmlink, the path is reported from the point of the
synthetic firmlink and not the real path. For example:
Real path:
/System/Volumes/Data/network/working/directory/foo.txt
Synthetic firmlink:
/network -> /System/Volumes/Data/network
FSEvents path:
/network/working/directory/foo.txt
This causes the FSEvents path to not match against the worktree
directory.
There are several ways in which synthetic firmlinks can be created:
they can be defined in /etc/synthetic.conf, the automounter can create
them, and there may be other means. Simply reading /etc/synthetic.conf
is insufficient. No matter what process creates synthetic firmlinks,
they all get created in the root directory.
Therefore, in order to deal with synthetic firmlinks, the root directory
is scanned and the first possible synthetic firmink that, when resolved,
is a prefix of the worktree is used to map FSEvents paths to worktree
paths.
Signed-off-by: Eric DeCosta <edecosta@mathworks.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Provide a common interface for getting basic filesystem information
including filesystem type and whether the filesystem is remote.
Refactor existing code for getting basic filesystem info and detecting
remote file systems to the new interface.
Refactor filesystem checks to leverage new interface. For macOS,
error-out if the Unix Domain socket (UDS) file is on a remote
filesystem.
Signed-off-by: Eric DeCosta <edecosta@mathworks.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
