Warnings with custom contexts and \addQuote

Thank you for all your work on LilyPond!

I’ve found that when defining a stream of music using \addQuote, if the music contains a custom context, “cannot create context” warnings are thrown when the music is passed to \addQuote.

I suspect that these warnings are accurate—the custom context really can’t be created—but I’m reporting it as a bug because, as far as I can tell, there’s no way to cause \addQuote to create the custom context. (The warnings can be silenced with ly:expect-warning, however.)

I can reproduce this in LilyPond 2.24.4 and 2.25.27. Note that in 2.24.4, the behavior is a little different; LilyPond 2.24.4 reports that converting to a PDF failed with “fatal error: failed files: [filename]”, but the PDF is actually written. LilyPond 2.25.27 reports “Success: compilation successfully completed”.

Here is a minimal example:

\version "2.25.24"

\layout {
  \context {
    \name MyContext
    \type Engraver_group
    \alias Voice
  }
  \inherit-acceptability MyContext Voice
}

music = \new MyContext { s1 }

\score {
  \new Staff { \music }
}

% #(ly:expect-warning (G_ "cannot create context: ~a") "MyContext")
\addQuote "music" \music