Your proposed behavior is broken too, since it changes the directory of the environment...

Fixed it as e93d8e2.

https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2020-3719cd8b93

The cmake-configure script is executed, not sourced. So changing the current working directory inside the script does not change the current working directory in the calling shell.

[ellert@ellert ~]$ cat a.sh
#!/bin/bash
mkdir -p x
cd x
[ellert@ellert ~]$ pwd
/home/ellert
[ellert@ellert ~]$ ./a.sh
[ellert@ellert ~]$ pwd
/home/ellert
[ellert@ellert ~]$ . ./a.sh
[ellert@ellert x]$ pwd
/home/ellert/x

Yes, but the arguments passed to CMake would be wrong, since we don't assume you're changing directories.

And the assumption that the directory will always be a level up is flawed, unfortunately, because you can change %_vpath_builddir and %_vpath_srcdir to whatever you please.