toRangeCfi required stored start and end CFIs to share a base path and
otherwise fell back to a bare point CFI, which resolves to a collapsed
range and paints nothing - or painted from the wrong anchor after end
repair. A legitimate selection crossing inline elements anchors at two
different text nodes by definition, so requiring a shared base path
discarded correct endpoints.
Build the range parent from the endpoints' longest shared step prefix
(down to the bare spine step when needed) and emit each divergent
remainder per the EPUB CFI range grammar, epubcfi(parent,start,end).
Degenerate-end repair (missing end, or end before start) now only
applies when both sides terminate on the SAME node - equal remaining
step count with different step values is a valid two-node range, not a
degenerate pair; document order is verified for those instead.
Verified with foliate's own parser against the real chapter XHTML:
ranges resolve to exactly the selected text for same-node, two-node,
and repaired-degenerate cases.
John O'Keefe
93a468b435