Tonight's failures all traced to one blind spot: the converter could
only reason about text within a single block. A position at a chapter
heading sends walk-up context (heading + the paragraphs below, joined by
the plugin's block capture); a selection can span several paragraphs.
Neither shape could be verified (containment compared one block against
a multi-block quote, so the CORRECT structural landing at the heading
was rejected) nor matched by text search (it never crossed block
boundaries). The ladder then fell to the percentage rung — which labeled
its char-count guess Precision "exact" — and that confidently-wrong CFI
was stored: reading positions reopened paragraphs away from the true
spot, and a highlight echo overwrote the row's good web CFIs with a
garbage start anchor that made the highlight unpaintable ("disappeared").
Four changes, all in the forward converter and its consumers:
- Quote verification: after the structural walk lands, read the
whitespace-normalized document text forward from the landing point
(crossing block boundaries; inline spans join directly so drop-cap
splits still read as one word). A usable context must be a prefix of
that stream — which is exactly what device captures are: the text from
the position onward, or the selection between two anchors. The old
single-block containment checks remain as secondary acceptance.
- Cross-block text search: the search rung matches against the whole
document flattened in reading order, with every rune mapped back to
its source node and offset. A context spanning blocks now matches, and
the matched extent yields a true range end (EndEPUBCFI) that
highlights use as their end anchor, threaded through the facade as
CanonicalLocator.EndCFI.
- Honest labels: the percentage rung returns Precision "percentage" —
a char-count estimate must never masquerade as an exact anchor.
- Confident-only storage: progress adopts a converted locator solely at
structural/exact precision (section hrefs keep their legacy handling;
anything lower stores percentage only), and highlight conversion
returns CFIs only at structural/exact precision — a low-confidence
echo yields empty, which applyLWW coalescing turns into preservation
of the row's existing web CFIs instead of clobbering them.
Tests: walk-up context at a heading verifies structurally and lands in
the heading; a block-spanning context is found by search with a range
end landing in the following paragraph; the percentage rung is honestly
labeled; all drop-cap guards stay green.
john-okeefe
b6f507b9e5