FA-54709 / Accessibility interaction semantics / Member archive

Forward queries include a previous line end in a gap · case 04

Forward queries include a previous line end in a gap.

Member previewVariant 4 · 3 implementations · 9 checks per implementation

Case contract

Input [text,lines,offset,affinity] lines ordered nonoverlapping [start,end,hard_break] in codepoint coordinates. Each line covers half-open text range; an offset on shared line boundary selects next line for forward affinity, previous for backward. Final document-end offset selects final line. Empty text with one empty line is valid. Return [index,start,end,text_segment,hard_break], or None for offsets outside text or gaps. Newline characters are included only if line bounds include them. No text wrapping is performed.

Why this case matters

Offline accessibility bridge model with explicit policy; useful for testing semantic API adapters independently of browser implementations.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
contract fixture 5	`[0, 0, 1, "a", false]`	`null`	Failed

MEMBER ARCHIVE

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