bash completions have undocumented dependency for _filedir etc, produce "command not found" otherwise
All three completion files in https://gitlab.kitware.com/cmake/cmake/-/tree/v3.27.8/Auxiliary/bash-completion depend on the presence of shell helper functions such as _filedir, __split_longopt, _ncpus, and _parse_help. These are not built-in bash functions, but could be provided by various completion libraries. None of the documentation or packaging metadata, or even comments in these files, mentions this dependency.
At the very least, it should be mentioned, including naming a specific completion library which provides the necessary functions with behavior compatible with these scripts.
Ideally, this dependency would not exist, and the completions would function on their own.