mirror of
https://github.com/deepseek-ai/deepseek-harness
synced 2026-08-15 21:04:50 +00:00
f8ef2cf36b
Review caught a real divergence the earlier measurements missed: mirroring an offset is only correct while both layers can reach it, and for a draft ending in a newline the backdrop could not. A textarea reserves a line box for the caret after a final newline. `white-space: pre-wrap` collapses a text node's trailing newline and generates none. So a draft ending in a newline made the backdrop exactly one line shorter than the textarea — measured 628 against 652 — and the mirrored assignment clamped, leaving the glyphs one line behind the caret at the very bottom of the draft. The backdrop now carries the same trailing-line sentinel the mirror div has carried all along: its content is the decoration walk plus one newline. The same pre-wrap collapse absorbs it when the draft does not end in a newline, so it costs no height in the ordinary case, and it supplies the missing line box when it does. Verified in isolation first: a bare pre-wrap div measures 180/180/198 against a textarea's 180/198/216 for zero, one and two trailing newlines, and 180/198/216 with the sentinel. Coverage for the shape that exposed it: the browser scenario asserts the two extents are equal before asserting the glyphs reach the end, observing each layer's maximum by asking for an impossible offset and reading back the clamp rather than computing it from scrollHeight, and the golden records the relation. The unit spec pins the backdrop's text as the draft plus exactly one newline. Removing the sentinel fails both, the e2e with the same 628 against 652. The scrollbar-gutter half of the same review point does not reproduce here: both layers measure clientWidth 776 against a border box of 776 while the draft overflows, so this engine's textarea scrollbar is an overlay and takes no width out of the wrap.