I just updated arcanist and libphputil today and I can not use arcanist anymore as I am getting:
$ arc diff HEAD^ [2015-07-10 08:13:15] ERROR 2: is_link(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/srv/http/:/home/:/tmp/:/usr/share/pear/:/usr/share/webapps/:/etc/:/usr/share/php/) at [/usr/share/php/libphutil/src/filesystem/Filesystem.php:821] arcanist(), phutil() #0 is_link(string) called at [<phutil>/src/filesystem/Filesystem.php:821] #1 Filesystem::resolvePath(string) called at [<phutil>/src/filesystem/Filesystem.php:744] #2 Filesystem::walkToRoot(string) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:72] #3 ArcanistWorkingCopyIdentity::newFromPathWithConfig(string, NULL) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:22] #4 ArcanistWorkingCopyIdentity::newFromPath(string) called at [<arcanist>/scripts/arcanist.php:113] [2015-07-10 08:13:15] ERROR 2: realpath(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/srv/http/:/home/:/tmp/:/usr/share/pear/:/usr/share/webapps/:/etc/:/usr/share/php/) at [/usr/share/php/libphutil/src/filesystem/Filesystem.php:828] arcanist(), phutil() #0 realpath(string) called at [<phutil>/src/filesystem/Filesystem.php:828] #1 Filesystem::resolvePath(string) called at [<phutil>/src/filesystem/Filesystem.php:744] #2 Filesystem::walkToRoot(string) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:72] #3 ArcanistWorkingCopyIdentity::newFromPathWithConfig(string, NULL) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:22] #4 ArcanistWorkingCopyIdentity::newFromPath(string) called at [<arcanist>/scripts/arcanist.php:113] [2015-07-10 08:13:15] ERROR 2: realpath(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/srv/http/:/home/:/tmp/:/usr/share/pear/:/usr/share/webapps/:/etc/:/usr/share/php/) at [/usr/share/php/libphutil/src/filesystem/Filesystem.php:845] arcanist(), phutil() #0 realpath(string) called at [<phutil>/src/filesystem/Filesystem.php:845] #1 Filesystem::resolvePath(string) called at [<phutil>/src/filesystem/Filesystem.php:744] #2 Filesystem::walkToRoot(string) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:72] #3 ArcanistWorkingCopyIdentity::newFromPathWithConfig(string, NULL) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:22] #4 ArcanistWorkingCopyIdentity::newFromPath(string) called at [<arcanist>/scripts/arcanist.php:113] [2015-07-10 08:13:15] ERROR 2: is_link(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/srv/http/:/home/:/tmp/:/usr/share/pear/:/usr/share/webapps/:/etc/:/usr/share/php/) at [/usr/share/php/libphutil/src/filesystem/Filesystem.php:749] arcanist(), phutil() #0 is_link(string) called at [<phutil>/src/filesystem/Filesystem.php:749] #1 Filesystem::walkToRoot(string) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:72] #2 ArcanistWorkingCopyIdentity::newFromPathWithConfig(string, NULL) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:22] #3 ArcanistWorkingCopyIdentity::newFromPath(string) called at [<arcanist>/scripts/arcanist.php:113] [2015-07-10 08:13:15] ERROR 2: file_exists(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/srv/http/:/home/:/tmp/:/usr/share/pear/:/usr/share/webapps/:/etc/:/usr/share/php/) at [/usr/share/php/libphutil/src/filesystem/Filesystem.php:916] arcanist(), phutil() #0 file_exists(string) called at [<phutil>/src/filesystem/Filesystem.php:916] #1 Filesystem::pathExists(string) called at [<phutil>/src/filesystem/Filesystem.php:1005] #2 Filesystem::assertExists(string) called at [<phutil>/src/filesystem/Filesystem.php:869] #3 Filesystem::isDescendant(string, string) called at [<phutil>/src/filesystem/Filesystem.php:761] #4 Filesystem::walkToRoot(string) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:72] #5 ArcanistWorkingCopyIdentity::newFromPathWithConfig(string, NULL) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:22] #6 ArcanistWorkingCopyIdentity::newFromPath(string) called at [<arcanist>/scripts/arcanist.php:113] [2015-07-10 08:13:15] ERROR 2: is_link(): open_basedir restriction in effect. File(/) is not within the allowed path(s): (/srv/http/:/home/:/tmp/:/usr/share/pear/:/usr/share/webapps/:/etc/:/usr/share/php/) at [/usr/share/php/libphutil/src/filesystem/Filesystem.php:916] arcanist(), phutil() #0 is_link(string) called at [<phutil>/src/filesystem/Filesystem.php:916] #1 Filesystem::pathExists(string) called at [<phutil>/src/filesystem/Filesystem.php:1005] #2 Filesystem::assertExists(string) called at [<phutil>/src/filesystem/Filesystem.php:869] #3 Filesystem::isDescendant(string, string) called at [<phutil>/src/filesystem/Filesystem.php:761] #4 Filesystem::walkToRoot(string) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:72] #5 ArcanistWorkingCopyIdentity::newFromPathWithConfig(string, NULL) called at [<arcanist>/src/workingcopyidentity/ArcanistWorkingCopyIdentity.php:22] #6 ArcanistWorkingCopyIdentity::newFromPath(string) called at [<arcanist>/scripts/arcanist.php:113] Usage Exception: `arc diff` is only supported under git, hg, svn.