From d4adce7e004bf5855aad7f68dbf89eb913ddc96c Mon Sep 17 00:00:00 2001 From: Michael Grant Date: Tue, 22 Sep 2026 17:16:25 +0100 Subject: [PATCH] screen-redraw: use the prompt's own screen to clip its damage range redraw_damage_draw_pane_prompt() recomposes a pane's separately rendered prompt (wp->prompt) over a damaged sub-range of a REDRAW_SPAN_PANE span, reusing the (x, n) range that redraw_client_damage() already clipped and grew against the pane's own *content* grid (wp->screen) via redraw_damage_grow_span_clip(). That growing exists specifically to avoid splitting a wide character at the range's edge - but the prompt is drawn into its own, freshly allocated one-line screen with no relationship to the content grid, so a range that's clean (or correctly grown) for the content can still land mid-character in the prompt's own grid. This is invisible whenever the pane's content is plain ASCII: the content grid has no padding cells to find, so redraw_damage_grow_span_clip() never grows the range at all, and the raw geometric range - however it landed - is passed straight through to the prompt. If that range's end lands right after a base cell whose padding half falls just outside it, tty_draw_line() has no room left for that cell's second column (tty_draw_line_get_empty()'s gc->data.width > nx check) and blanks it entirely, even though the pane's own content never needed the fix at all. Reproduced with a floating pane's CJK prompt straddling the boundary between two tiled panes underneath it: a palette change (OSC 4) in one of the tiled panes triggers a redraw of its own rectangle, which is occluded by the floating pane but still geometrically overlaps its prompt row, recomposing a partial range of the prompt that cuts through a character. Fix: extract the grid-probing tail of redraw_span_cell_is_padding() into redraw_screen_cell_is_padding(), usable against any screen, and add redraw_damage_grow_screen_clip() - the same left/right one-step growth as redraw_damage_grow_span_clip(), but against an explicit screen and column origin. redraw_damage_draw_pane_prompt() now re-derives its own (x0, x1) range from the caller's (x, n) by growing it against the prompt's own screen before drawing, clamped to the span so it can't bleed into a neighbouring one. New regress/floating-pane-prompt-wide-character.sh constructs the exact tiled-pane-boundary scenario above and checks the CJK prompt text is intact after the trigger. Verified failing 3/3 against the pre-fix code (a character is blanked) and passing 5/5 standalone plus 2/2 in the full regress suite (twice, since this touches the same damage-composition path as every other redraw) against the fix, with no other tests newly broken (prompt-words-history.sh and the untracked image-support scratch tests are pre-existing, unrelated failures). Co-Authored-By: Claude Sonnet 5 --- .../floating-pane-prompt-wide-character.sh | 179 ++++++++++++++++++ screen-redraw.c | 59 +++++- 2 files changed, 229 insertions(+), 9 deletions(-) create mode 100755 regress/floating-pane-prompt-wide-character.sh diff --git a/regress/floating-pane-prompt-wide-character.sh b/regress/floating-pane-prompt-wide-character.sh new file mode 100755 index 000000000..cdd892a54 --- /dev/null +++ b/regress/floating-pane-prompt-wide-character.sh @@ -0,0 +1,179 @@ +#!/bin/sh + +# A damage rectangle's clip range is grown to avoid splitting a wide +# character, but redraw_damage_grow_span_clip() (screen-redraw.c) only ever +# checks the span's own pane *content* grid (wp->screen) for that. For a +# REDRAW_SPAN_PANE span, that same range is then also handed to +# redraw_damage_draw_pane_prompt() to recompose the pane's separately +# rendered prompt (wp->prompt, e.g. from "command-prompt -P") over the +# damaged sub-range - but the prompt is drawn into its own, freshly +# allocated one-line screen, unrelated to the pane's content grid, so a +# range grown (or left ungrown) against the content is not necessarily +# grown correctly for the prompt's own wide characters. +# +# This is invisible when the pane's own content is plain ASCII (as here): +# redraw_damage_grow_span_clip() never finds anything to grow against, so +# the raw, ungrown geometric range is passed straight through to the +# prompt - and if that range's edge lands mid-character in the *prompt's* +# grid, tty_draw_line() clears the character it cuts through +# (tty_draw_line_get_empty()'s gc->data.width > nx check, for a trailing +# base cell with no room left for its padding half). +# +# The trigger is a palette change (OSC 4) in a tiled pane that is one half +# of a vertical split running the full height of the window - occluded +# under the floating pane, but still geometrically triggering a redraw of +# its own rectangle. Positioned so the split boundary falls inside the +# floating pane's own CJK prompt, this reproduces exactly Codex's report: +# "a floating pane containing a CJK prompt across a tiled-pane boundary - +# a palette update in the tiled pane blanks a prompt character." + +PATH=/bin:/usr/bin +TERM=screen +LC_ALL=C.UTF-8 +export PATH TERM LC_ALL + +[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux) + +DIR=$(mktemp -d) || exit 1 +cd "$DIR" || exit 1 +INNER="$TEST_TMUX -Lpromptwide-inner-$$ -f/dev/null" +OUTER="$TEST_TMUX -Lpromptwide-outer-$$ -f/dev/null" +EMITTER=$DIR/emitter.pl +CAPTURE=$DIR/capture +FLOAT= + +fail() +{ + echo "$*" >&2 + [ -s "$CAPTURE" ] && cat "$CAPTURE" >&2 + exit 1 +} + +cleanup() +{ + $OUTER kill-server 2>/dev/null + $INNER kill-server 2>/dev/null + cd / + rm -rf "$DIR" +} +trap cleanup 0 1 15 + +wait_for_client() +{ + i=0 + while [ "$i" -lt 50 ]; do + CLIENT=$($INNER list-clients -F '#{client_name}' 2>/dev/null) + [ -n "$CLIENT" ] && return 0 + sleep 0.1 + i=$((i + 1)) + done + fail "inner client did not attach" +} + +wait_outer_has() +{ + marker=$1 + i=0 + while [ "$i" -lt 50 ]; do + $OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true + grep -q "$marker" "$CAPTURE" && return 0 + sleep 0.1 + i=$((i + 1)) + done + fail "outer client did not show $marker" +} + +wait_prompt_row_intact() +{ + i=0 + while [ "$i" -lt 50 ]; do + $OUTER capture-pane -p -t outer:0.0 >"$CAPTURE" 2>/dev/null || true + line=$(sed -n "${PROMPTROW}p" "$CAPTURE") + case $line in + *"$PROMPTTEXT"*) return 0 ;; + esac + sleep 0.1 + i=$((i + 1)) + done + fail "the CJK prompt was not intact after the palette-triggered damage - got: $line" +} + +cat >"$EMITTER" <<'PERL' +use strict; +use warnings; + +$| = 1; +my $line = ; +print "\e]4;1;rgb:11/22/33\e\\"; +sleep 100; +PERL + +$INNER new-session -d -s inner -x 60 -y 12 "perl '$EMITTER'" || exit 1 +$INNER set-option -g status off || exit 1 +$INNER set-option -g window-size manual || exit 1 +LEFT=$($INNER list-panes -t inner -F '#{pane_id}') || exit 1 + +# Split so the boundary between the two tiled panes falls at column 17 - +# used below to pick a floating-pane column that lands the boundary +# mid-character inside the prompt. +RIGHT=$($INNER split-window -t inner -h -l 43 -PF '#{pane_id}' \ + 'sleep 100') || exit 1 +RX=$($INNER display-message -p -t "$RIGHT" '#{pane_left}') || exit 1 + +# Create the floating pane, then check its actual resulting position (the +# border-framing offset added to -X is not something to hand-compute). Try +# adjacent starting columns until the split boundary lands on an odd +# (padding-half) column of the prompt's own numbering, and within the +# prompt's 12-column width. +startx=10 +tries=0 +while [ "$tries" -lt 4 ]; do + [ -n "$FLOAT" ] && $INNER kill-pane -t "$FLOAT" 2>/dev/null + FLOAT=$($INNER new-pane -d -PF '#{pane_id}' -x 24 -y 5 -X "$startx" \ + -Y 2 "sh -c 'i=0; while [ \$i -lt 10 ]; do \ +printf AAAAAAAAAAAAAAAAAAAAAA\\\\n; i=\$((i+1)); done; sleep 100'") || + exit 1 + sleep 0.2 + X1=$($INNER display-message -p -t "$FLOAT" '#{pane_left}') + Y1=$($INNER display-message -p -t "$FLOAT" '#{pane_top}') + H1=$($INNER display-message -p -t "$FLOAT" '#{pane_height}') + local=$((RX - X1 - 1)) + if [ "$local" -ge 1 ] && [ "$local" -le 11 ] && + [ $((local % 2)) -eq 1 ]; then + break + fi + startx=$((startx + 1)) + tries=$((tries + 1)) +done +local=$((RX - X1 - 1)) +[ "$local" -ge 1 ] && [ "$local" -le 11 ] && [ $((local % 2)) -eq 1 ] || + fail "could not find bad-parity starting column" + +$OUTER new-session -d -s outer -x 60 -y 12 'sleep 100' || exit 1 +$OUTER set-option -g status off || exit 1 +$OUTER set-option -g window-size manual || exit 1 +$OUTER set-option -g default-terminal screen-256color || exit 1 +$OUTER respawn-pane -k -t outer:0.0 \ + "$TEST_TMUX -Lpromptwide-inner-$$ -f/dev/null attach-session -t inner" || + exit 1 + +wait_for_client +wait_outer_has AAAAAAAAAAAAAAAAAAAAAA +CLIENT=$($INNER list-clients -F '#{client_name}') || exit 1 + +$INNER select-pane -t "$FLOAT" || exit 1 +PROMPTTEXT=$(printf '\344\270\255' | perl -CSD -ne 'print $_ x 6') +$INNER command-prompt -b -P -t "$CLIENT" -p "$PROMPTTEXT" \ + 'display-message -- %1' || exit 1 +wait_outer_has "$PROMPTTEXT" + +PROMPTROW=$((Y1 + H1)) + +# Trigger the damage: unblock the emitter so it fires the palette change in +# the left tiled pane, which is occluded under (but geometrically overlaps) +# the floating pane's prompt row. +$INNER send-keys -t "$LEFT" Enter || exit 1 + +wait_prompt_row_intact + +exit 0 diff --git a/screen-redraw.c b/screen-redraw.c index 31b760fae..d8f4bc0fa 100644 --- a/screen-redraw.c +++ b/screen-redraw.c @@ -2069,6 +2069,18 @@ redraw_damage_refresh_status(struct redraw_draw_ctx *dctx, wp->status_serial = redraw_status_serial; } +/* Whether the cell at (px, py) in screen s is a padding cell. */ +static int +redraw_screen_cell_is_padding(struct screen *s, u_int px, u_int py) +{ + struct grid_cell gc; + + if (px >= screen_size_x(s)) + return (0); + grid_view_get_cell(s->grid, px, py, &gc); + return ((gc.flags & GRID_FLAG_PADDING) != 0); +} + /* * Whether the cell at scene x-coordinate x within this span is the second * (padding) half of a wide character - the condition under which growing a @@ -2092,7 +2104,6 @@ static int redraw_span_cell_is_padding(struct redraw_span *span, u_int x) { struct screen *s; - struct grid_cell gc; u_int px, py; switch (span->data.type) { @@ -2114,10 +2125,7 @@ redraw_span_cell_is_padding(struct redraw_span *span, u_int x) default: return (1); } - if (px >= screen_size_x(s)) - return (0); - grid_view_get_cell(s->grid, px, py, &gc); - return ((gc.flags & GRID_FLAG_PADDING) != 0); + return (redraw_screen_cell_is_padding(s, px, py)); } /* @@ -2144,6 +2152,26 @@ redraw_damage_grow_span_clip(struct redraw_span *span, u_int *xp, u_int *endp) (*endp)++; } +/* + * As redraw_damage_grow_span_clip(), but against an explicit screen: px0 is + * the column in that screen corresponding to span->x, py the row. Used for + * a span's separately rendered content (e.g. a pane's prompt) that isn't + * span->data.p.wp->screen (or whichever grid redraw_span_cell_is_padding() + * would otherwise consult for this span's type), and so has its own, + * unrelated wide-character boundaries at the same columns. + */ +static void +redraw_damage_grow_screen_clip(struct redraw_span *span, struct screen *s, + u_int px0, u_int py, u_int *xp, u_int *endp) +{ + if (*xp > span->x && + redraw_screen_cell_is_padding(s, px0 + (*xp - span->x), py)) + (*xp)--; + if (*endp < span->x + span->width && + redraw_screen_cell_is_padding(s, px0 + (*endp - span->x), py)) + (*endp)++; +} + /* Recompose a pane's prompt over a damaged section of its display row. */ static void redraw_damage_draw_pane_prompt(struct redraw_draw_ctx *dctx, @@ -2153,7 +2181,7 @@ redraw_damage_draw_pane_prompt(struct redraw_draw_ctx *dctx, struct window_pane *wp = span->data.p.wp; struct tty *tty = &scene->c->tty; struct screen screen; - u_int px, width, prompt_y; + u_int px, width, prompt_y, x0, x1; if (wp->prompt == NULL || wp->sx == 0 || wp->sy == 0) return; @@ -2165,12 +2193,25 @@ redraw_damage_draw_pane_prompt(struct redraw_draw_ctx *dctx, return; redraw_make_pane_prompt(wp, &screen); - px = span->data.p.px + (x - span->x); + + /* + * x and n were clipped and grown against wp->screen, whose character + * boundaries have nothing to do with the prompt's separately + * rendered screen - realign the range on the prompt's own grid + * instead, clamped to this span so it cannot bleed into a + * neighbouring one. + */ + x0 = x; + x1 = x + n; + redraw_damage_grow_screen_clip(span, &screen, span->data.p.px, 0, &x0, + &x1); + + px = span->data.p.px + (x0 - span->x); if (px < screen_size_x(&screen)) { - width = n; + width = x1 - x0; if (width > screen_size_x(&screen) - px) width = screen_size_x(&screen) - px; - tty_draw_line(tty, &screen, px, 0, width, x, y, NULL); + tty_draw_line(tty, &screen, px, 0, width, x0, y, NULL); } screen_free(&screen); }