exa now ignores errors when checking for extended attributes when the user didn’t explicitly demand that they be checked. If a file does have xattrs, it’ll still display the @ in the permissions column; errors will now just cause the @ to be hidden instead.
This changed a lot of the xtests, which were displaying the error message in a few situations. Those tests have gained @-suffixed companions so the actual error messages can still be tested.
Fixes#178 (finally)
