gh-145448: Fix REPL tab completion cursor position in pending wrap state#145727
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mvanhorn wants to merge 1 commit intopython:mainfrom
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gh-145448: Fix REPL tab completion cursor position in pending wrap state#145727mvanhorn wants to merge 1 commit intopython:mainfrom
mvanhorn wants to merge 1 commit intopython:mainfrom
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…rap state When __write_changed_line writes to the last column of the terminal, the cursor enters "pending wrap" state where it physically stays at width-1. However, posxy was recording width, causing subsequent CUB (Cursor Backward) calculations to overshoot by one cell. Cap posxy x-coordinate at width-1 to match the physical cursor position in pending wrap state. This fixes the cursor moving backward during tab completion in xterm and Ghostty. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Fixes #145448
Summary
When the PyREPL's
__write_changed_linewrites to the last column of the terminal, the cursor enters "pending wrap" state - it physically stays at columnwidth-1butposxywas recordingwidth. This caused subsequent CUB (Cursor Backward) escape sequences to overshoot by one cell, moving the cursor one position too far left.Root cause: In
unix_console.py, three code paths in__write_changed_linesetposxyto the full line width without accounting for pending wrap state. When the cursor is later moved back (e.g., to return to the input line after showing "[ complete but not unique ]"), the CUB count is calculated astarget_x - widthinstead oftarget_x - (width-1), producing one extra backward movement.Fix: Cap
posxy[0]atself.width - 1when writing reaches the terminal edge. This matches the physical cursor position in pending wrap state, so CUB calculations produce the correct count.Why Terminal.app isn't affected: Terminal.app compensates by subtracting 1 from CUB in pending wrap state. xterm and Ghostty do not compensate, matching the spec more strictly.
Test plan
test_pyrepltests passposxyassignment paths in__write_changed_lineThis contribution was developed with AI assistance (Claude Code).