when a change happens on a clearcase directory, content of previous and new version is retrieved by listing directory content, however there could be private files, these private files should be ignored.
Moreover, this directory comparison mecanism must work when snap or dynamic view

touch dir/private_files.txt

post-review --revision-range=dir@/main/1:dir@/main/2 --output-diff

dir/private_files.txt is no more listed in diff