add: notify when adding a file that would cause a case-folding collision On a case-sensitive file system, files can be added with names that differ only in case (a "case collision"). This would cause an error on case-insensitive filesystems. A warning or error is now given for such collisions, depending on the value of ui.portablefilenames ('warn', 'abort', or 'ignore'): $ touch file File $ hg add --config ui.portablefilenames=abort File abort: possible case-folding collision for File $ hg add File warning: possible case-folding collision for File