Edition Engraver master vs refactor override branch: changing bound-details

[Stefano Troncaro]

Hi all, long time since I posted here, hope you all have been well!

While using the Edition Engraver today I noticed that the following override works in the old refactor override branch, while on the current master it prints a textless spanner and a warning:

\version "2.19.80"

\include "oll-core/package.ily"
\loadPackage edition-engraver

\consistToContexts #edition-engraver Voice
\addEdition test

\editionMod test 1 0 Voice.A {
  \override TextSpanner.bound-details.left.text = "span this"
  <>\startTextSpan
}
\editionMod test 2 3/4 Voice.A \stopTextSpan

\new Staff {
  \new Voice \relative {
    c' d e f g a b c
  }
}

Said warning is

warning: type check for `bound-details' failed; value `"span this"' must be of type `list'

In the current master I could set this like this:

\override TextSpanner.bound-details = #'((left . ((text . "span this"))))

but this has the undesirable effect of resetting all the other settings of the bound-details alist

Without having been able to dive down into the code, this looks like a simple issue with type checking, but I realize this may have been implemented this way to circumvent other problems.

So, how can I achieve this with the current master? Or should I go back to using the earlier branch until this is solved?

Thanks for your help,

Stéfano