bug#46908: 28.0.50; Dozens of spurious markers in buffer-undo-list

[martin rudalics]

> `add-to-history' has no relevance here, no.  There mere existence of a
> marker in any buffer does, IIUC, cause it to be referenced by
> buffer-undo-list sooner or later, because undoing and redoing inside
> text containing a marker is not always without ambiguity regarding
> marker positioning, so the undo system adds hints to buffer-undo-list
> how these markers must be placed/repositioned.

Suppose I put a marker into a buffer and do ten distinct modifications
of the buffer, each modifying that marker's position.  So I get ten
additional entries in the undo list.  Does this mean I get ten copies of
that marker too?

martin