fix: undo/redo produces wrong results when text contains multiple newlines#852
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Giggitycountless wants to merge 1 commit intomicrosoft:mainfrom
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fix: undo/redo produces wrong results when text contains multiple newlines#852Giggitycountless wants to merge 1 commit intomicrosoft:mainfrom
Giggitycountless wants to merge 1 commit intomicrosoft:mainfrom
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…lines The undo_redo reinsert loop used `lines_fwd(added, beg, 0, 1)` to find newlines, but lines_fwd is designed to seek to a specific line number. On the second iteration, line >= line_stop causes lines_fwd to return immediately without advancing, resulting in only the first line being reinserted (or an infinite loop in debug builds). Replaced with `memchr2(b'\r', b'\n', ...)` which correctly iterates through all newlines regardless of position. Also properly handles \r\n as a single newline unit to avoid double-inserting line endings in CRLF buffers. Fixes microsoft#834
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What changed
Fixes the undo/redo reinsert loop in
TextBuffer::undo_redo()that produces incorrect results when the edited text contains multiple newlines.Root cause
The reinsert loop used
simd::lines_fwd(added, beg, 0, 1)to find newlines in the recorded text. However,lines_fwdis designed to seek to a specific line number — on the second iteration,line >= line_stopcauses it to return immediately without advancing the offset. This means only the first line of a multi-line edit is reinserted during undo/redo.Fix
Replaced
lines_fwdwithsimd::memchr2(b'\r', b'\n', ...)which correctly finds the next newline byte regardless of iteration state. Also properly handles\r\nas a single newline unit to avoid double-inserting line endings in CRLF buffers.Tests added
8 regression tests covering:
Fixes #834