I haven't used perforce so am unfamiliar with any behaviors specific to that but the logic to have git automatically tell watchman to start watching repos is just a convenience feature. Feel free to remove/disable/modify it in the fsmonitor-watchman integration script:
if ($retry > 0 and $o->{error} and $o->{error} =~ m/unable to resolve root .* directory (.*) is not watched/) {
print STDERR "Adding '$git_work_tree' to watchman's watch list.\n";
$retry--;
qx/watchman watch "$git_work_tree"/;
Ben
> -----Original Message-----
> From: Luke Diamand [mailto:luke@xxxxxxxxxxx]
> Sent: Monday, January 8, 2018 12:15 PM
> To: Git Users <git@xxxxxxxxxxxxxxx>
> Cc: Alex Vandiver <alexmv@xxxxxxxxxxx>; Ben Peart
> <Ben.Peart@xxxxxxxxxxxxx>
> Subject: git-p4 + watchman - watching the p4 repo?
>
> Hi!
>
> I could be wrong about this, but I when I tried mixing watchman with git-p4, I
> found that on "git p4 submit" it ended up watching the p4 repo, which seems
> a bit pointless (and was also very slow).
>
> $ [create git-p4 clone of some p4 repo]
> $ : >bar
> $ git add bar && git commit -m 'adding bar'
> $ git p4 submit --origin HEAD^ --shelve
> Perforce checkout for depot path //depot/ located at /tmp/p4/cli/
> Synchronizing p4 checkout...
> ... - file(s) up-to-date.
> Applying 4ce4057 change
> //depot/bar#1 - opened for edit
> Adding '/tmp/p4/cli' to watchman's watch list.
>
> Is there any way to stop it doing this?
>
> Thanks!
> Luke
