nullglob must be active before a glob is used on a potentially empty
directory. Call shopt immediately after the shebang line.
FixesQubesOS/qubes-issues#3552
Before, the script skipped none existing ro paths even if the path
existed below /rw. This would require someone who wants to use bind-dirs
only in TemplateBasedVM to ensure that the paths exist before the
bind-dirs script gets called.
This patch changes this behavior so that if the path exists below /rw, it
is ensured that an (empty) file/directory is present in ro (where the
corresponding path from /rw is then bind mounted over).
Requires: Docs update. I can open a PR when this PRs looks good.
Fixes limitation: "Does not work if the file / folder in question does
not already exist in the root image. I.e. a file that does not exist in
the root image cannot be bind mounted in the TemplateBasedVM."
Example use case: https://github.com/debops/ansible-persistent_paths
Tested on: Qubes OS 3.2; Debian 8 TemplateBasedVM (and Template)
Related to: https://github.com/QubesOS/qubes-issues/issues/2661
f4d367a6 dropped the check if the bind target exists and added
"--no-clobber" to the cp call. For directories this does not work as
desired: cp checks per (recursive) file instead of once for the
specified directory.
