[augeas-devel] Setting nodes with empty values (0.7 regression?)

[Matthew Palmer]

We've got an internal lens that, for various mostly-sane reasons, uses a key
with no value (because we want to set modifiers on it in subkeys).  In 0.5,
we could just do:

    set /files/etc/x/y/z/A null

And the save would succeed.  When we reloaded the file, we'd see

    /files/etc/x/y/z/A (none)

And all would be happy.  In 0.7, however, attempting to do this results in
the message:

message = Failed to match
    ({ /[^\001-\004\t\n ,/A-Z\\]+/ } | { /A|L|U|K|P/ })({ /[^\001-\004\t\n ,/A-Z\\]+/ } | { /A|L|U|K|P/ })*
  with tree
    { "A" = "null" }

Now, I expect this is due to the value matching code that got introduced a
while ago (so I guess this is all my own fault, in a way), but I'm wondering
if there's any way to work around this, or perhaps relax the requirement in
sublenses that don't have a value regex at all?

For reference, I can use "set /files/etc/x/y/z/A ''" to do the right thing
in augtool, but I need to do this edit in the Puppet type, which maintains
it's reputation for being epsilon short of being just too damned painful to
use.

- Matt