Jeff King [off-list ref] writes:

On Wed, Nov 18, 2020 at 08:04:13PM +0100, SZEDER Gábor wrote:

quoted

So to prevent nested prereqs from interfering with each other let's
evaluate each prereq in its own dedicated directory by appending the
prereq's name to the directory name, e.g. 'prereq-test-dir-SYMLINKS'.
In the test we check not only that the prereq test dir is still there,
but also that the inner prereq can't mess with the outer prereq's
files.

That sounds reasonable. I do wonder, though, whether simply creating the
prereq directory in the _current_ directory would be sufficient. Then
you'd get prereq-test-dir/prereq-test-dir for a nested invocation. But
the prereqs aren't supposed to care about which specific directory
they're in.

True.  That does sound conceptually simpler.  As we've already seen
the patch, I do not mind too deeply either way, though.

Thanks.