A paste put an instance of "bg" inside "bg" itself. It saved, loaded, and then
threw "symbol cycle in audio" out of nest/audio-tracks, because a container that
contains itself has no finite expansion.
place-symbol and ui/drag already refused that, each by asking
clip/contains-symbol?. Paste asks clip/problems instead, and problems did not
encode the invariant at all -- it checked missing symbols, pose tracks and audio
links, but never the placement graph. So the rule goes where every command is
already checked: paste, cut, duplicate, correction and the span ops all gate on
problems, so one rule covers them all.
Why it looked like a reasonable thing to do is the other half. place-symbol
copied the symbol's name onto the instance it made, and that copy went stale on
the next rename: the symbol read "bg" in its tab while an instance of it still
read "symbol-18", which is its id from before it was named. One object under two
names, with nothing on screen to connect them.
So instances are no longer given a name at creation, and clip/node-label reads
the symbol's name through on every render. :name on an instance now means only
what a person typed, which is what tells two instances of one symbol apart --
"8625 left" and "8625 right" of one "face" -- so an authored name still wins and
read-through is the fallback. The label logic was duplicated across four call
sites with three different fallback orders; location.cljs already read through
and the others did not. They now share one function.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>