Files
llmx/codex-rs/tui/src/pager_overlay.rs
Jeremy Rose f54a49157b Fix pager overlay clear between pages (#3952)
should fix characters sometimes hanging around while scrolling the
transcript.
2025-09-22 15:12:29 -07:00

837 lines
28 KiB
Rust

use std::io::Result;
use std::sync::Arc;
use std::time::Duration;
use crate::history_cell::HistoryCell;
use crate::render::line_utils::push_owned_lines;
use crate::tui;
use crate::tui::TuiEvent;
use crossterm::event::KeyCode;
use crossterm::event::KeyEvent;
use crossterm::event::KeyEventKind;
use ratatui::buffer::Buffer;
use ratatui::layout::Rect;
use ratatui::style::Color;
use ratatui::style::Style;
use ratatui::style::Styled;
use ratatui::style::Stylize;
use ratatui::text::Line;
use ratatui::text::Span;
use ratatui::text::Text;
use ratatui::widgets::Clear;
use ratatui::widgets::Paragraph;
use ratatui::widgets::Widget;
use ratatui::widgets::WidgetRef;
pub(crate) enum Overlay {
Transcript(TranscriptOverlay),
Static(StaticOverlay),
}
impl Overlay {
pub(crate) fn new_transcript(cells: Vec<Arc<dyn HistoryCell>>) -> Self {
Self::Transcript(TranscriptOverlay::new(cells))
}
pub(crate) fn new_static_with_title(lines: Vec<Line<'static>>, title: String) -> Self {
Self::Static(StaticOverlay::with_title(lines, title))
}
pub(crate) fn handle_event(&mut self, tui: &mut tui::Tui, event: TuiEvent) -> Result<()> {
match self {
Overlay::Transcript(o) => o.handle_event(tui, event),
Overlay::Static(o) => o.handle_event(tui, event),
}
}
pub(crate) fn is_done(&self) -> bool {
match self {
Overlay::Transcript(o) => o.is_done(),
Overlay::Static(o) => o.is_done(),
}
}
}
// Common pager navigation hints rendered on the first line
const PAGER_KEY_HINTS: &[(&str, &str)] = &[
("↑/↓", "scroll"),
("PgUp/PgDn", "page"),
("Home/End", "jump"),
];
// Render a single line of key hints from (key, description) pairs.
fn render_key_hints(area: Rect, buf: &mut Buffer, pairs: &[(&str, &str)]) {
let key_hint_style = Style::default().fg(Color::Cyan);
let mut spans: Vec<Span<'static>> = vec![" ".into()];
let mut first = true;
for (key, desc) in pairs {
if !first {
spans.push(" ".into());
}
spans.push(Span::from(key.to_string()).set_style(key_hint_style));
spans.push(" ".into());
spans.push(Span::from(desc.to_string()));
first = false;
}
Paragraph::new(vec![Line::from(spans).dim()]).render_ref(area, buf);
}
/// Generic widget for rendering a pager view.
struct PagerView {
texts: Vec<Text<'static>>,
scroll_offset: usize,
title: String,
wrap_cache: Option<WrapCache>,
last_content_height: Option<usize>,
/// If set, on next render ensure this chunk is visible.
pending_scroll_chunk: Option<usize>,
}
impl PagerView {
fn new(texts: Vec<Text<'static>>, title: String, scroll_offset: usize) -> Self {
Self {
texts,
scroll_offset,
title,
wrap_cache: None,
last_content_height: None,
pending_scroll_chunk: None,
}
}
fn render(&mut self, area: Rect, buf: &mut Buffer) {
Clear.render(area, buf);
self.render_header(area, buf);
let content_area = self.scroll_area(area);
self.update_last_content_height(content_area.height);
self.ensure_wrapped(content_area.width);
// If there is a pending request to scroll a specific chunk into view,
// satisfy it now that wrapping is up to date for this width.
if let (Some(idx), Some(cache)) =
(self.pending_scroll_chunk.take(), self.wrap_cache.as_ref())
&& let Some(range) = cache.chunk_ranges.get(idx).cloned()
{
self.ensure_range_visible(range, content_area.height as usize, cache.wrapped.len());
}
// Compute page bounds without holding an immutable borrow on cache while mutating self
let wrapped_len = self
.wrap_cache
.as_ref()
.map(|c| c.wrapped.len())
.unwrap_or(0);
self.scroll_offset = self
.scroll_offset
.min(wrapped_len.saturating_sub(content_area.height as usize));
let start = self.scroll_offset;
let end = (start + content_area.height as usize).min(wrapped_len);
let wrapped = self.cached();
let page = &wrapped[start..end];
self.render_content_page_prepared(content_area, buf, page);
self.render_bottom_bar(area, content_area, buf, wrapped);
}
fn render_header(&self, area: Rect, buf: &mut Buffer) {
Span::from("/ ".repeat(area.width as usize / 2))
.dim()
.render_ref(area, buf);
let header = format!("/ {}", self.title);
header.dim().render_ref(area, buf);
}
// Removed unused render_content_page (replaced by render_content_page_prepared)
fn render_content_page_prepared(&self, area: Rect, buf: &mut Buffer, page: &[Line<'static>]) {
Clear.render(area, buf);
Paragraph::new(page.to_vec()).render_ref(area, buf);
let visible = page.len();
if visible < area.height as usize {
for i in 0..(area.height as usize - visible) {
let add = ((visible + i).min(u16::MAX as usize)) as u16;
let y = area.y.saturating_add(add);
Span::from("~")
.dim()
.render_ref(Rect::new(area.x, y, 1, 1), buf);
}
}
}
fn render_bottom_bar(
&self,
full_area: Rect,
content_area: Rect,
buf: &mut Buffer,
wrapped: &[Line<'static>],
) {
let sep_y = content_area.bottom();
let sep_rect = Rect::new(full_area.x, sep_y, full_area.width, 1);
Span::from("".repeat(sep_rect.width as usize))
.dim()
.render_ref(sep_rect, buf);
let percent = if wrapped.is_empty() {
100
} else {
let max_scroll = wrapped.len().saturating_sub(content_area.height as usize);
if max_scroll == 0 {
100
} else {
(((self.scroll_offset.min(max_scroll)) as f32 / max_scroll as f32) * 100.0).round()
as u8
}
};
let pct_text = format!(" {percent}% ");
let pct_w = pct_text.chars().count() as u16;
let pct_x = sep_rect.x + sep_rect.width - pct_w - 1;
Span::from(pct_text)
.dim()
.render_ref(Rect::new(pct_x, sep_rect.y, pct_w, 1), buf);
}
fn handle_key_event(&mut self, tui: &mut tui::Tui, key_event: KeyEvent) -> Result<()> {
match key_event {
KeyEvent {
code: KeyCode::Up,
kind: KeyEventKind::Press | KeyEventKind::Repeat,
..
} => {
self.scroll_offset = self.scroll_offset.saturating_sub(1);
}
KeyEvent {
code: KeyCode::Down,
kind: KeyEventKind::Press | KeyEventKind::Repeat,
..
} => {
self.scroll_offset = self.scroll_offset.saturating_add(1);
}
KeyEvent {
code: KeyCode::PageUp,
kind: KeyEventKind::Press | KeyEventKind::Repeat,
..
} => {
let area = self.scroll_area(tui.terminal.viewport_area);
self.scroll_offset = self.scroll_offset.saturating_sub(area.height as usize);
}
KeyEvent {
code: KeyCode::PageDown | KeyCode::Char(' '),
kind: KeyEventKind::Press | KeyEventKind::Repeat,
..
} => {
let area = self.scroll_area(tui.terminal.viewport_area);
self.scroll_offset = self.scroll_offset.saturating_add(area.height as usize);
}
KeyEvent {
code: KeyCode::Home,
kind: KeyEventKind::Press | KeyEventKind::Repeat,
..
} => {
self.scroll_offset = 0;
}
KeyEvent {
code: KeyCode::End,
kind: KeyEventKind::Press | KeyEventKind::Repeat,
..
} => {
self.scroll_offset = usize::MAX;
}
_ => {
return Ok(());
}
}
tui.frame_requester()
.schedule_frame_in(Duration::from_millis(16));
Ok(())
}
fn update_last_content_height(&mut self, height: u16) {
self.last_content_height = Some(height as usize);
}
fn scroll_area(&self, area: Rect) -> Rect {
let mut area = area;
area.y = area.y.saturating_add(1);
area.height = area.height.saturating_sub(2);
area
}
}
#[derive(Debug, Clone)]
struct WrapCache {
width: u16,
wrapped: Vec<Line<'static>>,
/// For each input Text chunk, the inclusive-excluded range of wrapped lines produced.
chunk_ranges: Vec<std::ops::Range<usize>>,
base_len: usize,
}
impl PagerView {
fn ensure_wrapped(&mut self, width: u16) {
let width = width.max(1);
let needs = match self.wrap_cache {
Some(ref c) => c.width != width || c.base_len != self.texts.len(),
None => true,
};
if !needs {
return;
}
let mut wrapped: Vec<Line<'static>> = Vec::new();
let mut chunk_ranges: Vec<std::ops::Range<usize>> = Vec::with_capacity(self.texts.len());
for text in &self.texts {
let start = wrapped.len();
for line in &text.lines {
let ws = crate::wrapping::word_wrap_line(line, width as usize);
push_owned_lines(&ws, &mut wrapped);
}
let end = wrapped.len();
chunk_ranges.push(start..end);
}
self.wrap_cache = Some(WrapCache {
width,
wrapped,
chunk_ranges,
base_len: self.texts.len(),
});
}
fn cached(&self) -> &[Line<'static>] {
if let Some(cache) = self.wrap_cache.as_ref() {
&cache.wrapped
} else {
&[]
}
}
fn is_scrolled_to_bottom(&self) -> bool {
if self.scroll_offset == usize::MAX {
return true;
}
let Some(cache) = &self.wrap_cache else {
return false;
};
let Some(height) = self.last_content_height else {
return false;
};
if cache.wrapped.is_empty() {
return true;
}
let visible = height.min(cache.wrapped.len());
let max_scroll = cache.wrapped.len().saturating_sub(visible);
self.scroll_offset >= max_scroll
}
/// Request that the given text chunk index be scrolled into view on next render.
fn scroll_chunk_into_view(&mut self, chunk_index: usize) {
self.pending_scroll_chunk = Some(chunk_index);
}
fn ensure_range_visible(
&mut self,
range: std::ops::Range<usize>,
viewport_height: usize,
total_wrapped: usize,
) {
if viewport_height == 0 || total_wrapped == 0 {
return;
}
let first = range.start.min(total_wrapped.saturating_sub(1));
let last = range
.end
.saturating_sub(1)
.min(total_wrapped.saturating_sub(1));
let current_top = self.scroll_offset.min(total_wrapped.saturating_sub(1));
let current_bottom = current_top.saturating_add(viewport_height.saturating_sub(1));
if first < current_top {
self.scroll_offset = first;
} else if last > current_bottom {
// Scroll just enough so that 'last' is visible at the bottom
self.scroll_offset = last.saturating_sub(viewport_height.saturating_sub(1));
}
}
}
pub(crate) struct TranscriptOverlay {
view: PagerView,
cells: Vec<Arc<dyn HistoryCell>>,
highlight_cell: Option<usize>,
is_done: bool,
}
impl TranscriptOverlay {
pub(crate) fn new(transcript_cells: Vec<Arc<dyn HistoryCell>>) -> Self {
Self {
view: PagerView::new(
Self::render_cells_to_texts(&transcript_cells, None),
"T R A N S C R I P T".to_string(),
usize::MAX,
),
cells: transcript_cells,
highlight_cell: None,
is_done: false,
}
}
fn render_cells_to_texts(
cells: &[Arc<dyn HistoryCell>],
highlight_cell: Option<usize>,
) -> Vec<Text<'static>> {
let mut texts: Vec<Text<'static>> = Vec::new();
let mut first = true;
for (idx, cell) in cells.iter().enumerate() {
let mut lines: Vec<Line<'static>> = Vec::new();
if !cell.is_stream_continuation() && !first {
lines.push(Line::from(""));
}
let cell_lines = if Some(idx) == highlight_cell {
cell.transcript_lines()
.into_iter()
.map(Stylize::reversed)
.collect()
} else {
cell.transcript_lines()
};
lines.extend(cell_lines);
texts.push(Text::from(lines));
first = false;
}
texts
}
pub(crate) fn insert_cell(&mut self, cell: Arc<dyn HistoryCell>) {
let follow_bottom = self.view.is_scrolled_to_bottom();
// Append as a new Text chunk (with a separating blank if needed)
let mut lines: Vec<Line<'static>> = Vec::new();
if !cell.is_stream_continuation() && !self.cells.is_empty() {
lines.push(Line::from(""));
}
lines.extend(cell.transcript_lines());
self.view.texts.push(Text::from(lines));
self.cells.push(cell);
self.view.wrap_cache = None;
if follow_bottom {
self.view.scroll_offset = usize::MAX;
}
}
pub(crate) fn set_highlight_cell(&mut self, cell: Option<usize>) {
self.highlight_cell = cell;
self.view.wrap_cache = None;
self.view.texts = Self::render_cells_to_texts(&self.cells, self.highlight_cell);
if let Some(idx) = self.highlight_cell {
self.view.scroll_chunk_into_view(idx);
}
}
fn render_hints(&self, area: Rect, buf: &mut Buffer) {
let line1 = Rect::new(area.x, area.y, area.width, 1);
let line2 = Rect::new(area.x, area.y.saturating_add(1), area.width, 1);
render_key_hints(line1, buf, PAGER_KEY_HINTS);
let mut pairs: Vec<(&str, &str)> = vec![("q", "quit"), ("Esc", "edit prev")];
if self.highlight_cell.is_some() {
pairs.push(("", "edit message"));
}
render_key_hints(line2, buf, &pairs);
}
pub(crate) fn render(&mut self, area: Rect, buf: &mut Buffer) {
let top_h = area.height.saturating_sub(3);
let top = Rect::new(area.x, area.y, area.width, top_h);
let bottom = Rect::new(area.x, area.y + top_h, area.width, 3);
self.view.render(top, buf);
self.render_hints(bottom, buf);
}
}
impl TranscriptOverlay {
pub(crate) fn handle_event(&mut self, tui: &mut tui::Tui, event: TuiEvent) -> Result<()> {
match event {
TuiEvent::Key(key_event) => match key_event {
KeyEvent {
code: KeyCode::Char('q'),
kind: KeyEventKind::Press,
..
}
| KeyEvent {
code: KeyCode::Char('t'),
modifiers: crossterm::event::KeyModifiers::CONTROL,
kind: KeyEventKind::Press,
..
}
| KeyEvent {
code: KeyCode::Char('c'),
modifiers: crossterm::event::KeyModifiers::CONTROL,
kind: KeyEventKind::Press,
..
} => {
self.is_done = true;
Ok(())
}
other => self.view.handle_key_event(tui, other),
},
TuiEvent::Draw => {
tui.draw(u16::MAX, |frame| {
self.render(frame.area(), frame.buffer);
})?;
Ok(())
}
_ => Ok(()),
}
}
pub(crate) fn is_done(&self) -> bool {
self.is_done
}
}
pub(crate) struct StaticOverlay {
view: PagerView,
is_done: bool,
}
impl StaticOverlay {
pub(crate) fn with_title(lines: Vec<Line<'static>>, title: String) -> Self {
Self {
view: PagerView::new(vec![Text::from(lines)], title, 0),
is_done: false,
}
}
fn render_hints(&self, area: Rect, buf: &mut Buffer) {
let line1 = Rect::new(area.x, area.y, area.width, 1);
let line2 = Rect::new(area.x, area.y.saturating_add(1), area.width, 1);
render_key_hints(line1, buf, PAGER_KEY_HINTS);
let pairs = [("q", "quit")];
render_key_hints(line2, buf, &pairs);
}
pub(crate) fn render(&mut self, area: Rect, buf: &mut Buffer) {
let top_h = area.height.saturating_sub(3);
let top = Rect::new(area.x, area.y, area.width, top_h);
let bottom = Rect::new(area.x, area.y + top_h, area.width, 3);
self.view.render(top, buf);
self.render_hints(bottom, buf);
}
}
impl StaticOverlay {
pub(crate) fn handle_event(&mut self, tui: &mut tui::Tui, event: TuiEvent) -> Result<()> {
match event {
TuiEvent::Key(key_event) => match key_event {
KeyEvent {
code: KeyCode::Char('q'),
kind: KeyEventKind::Press,
..
}
| KeyEvent {
code: KeyCode::Char('c'),
modifiers: crossterm::event::KeyModifiers::CONTROL,
kind: KeyEventKind::Press,
..
} => {
self.is_done = true;
Ok(())
}
other => self.view.handle_key_event(tui, other),
},
TuiEvent::Draw => {
tui.draw(u16::MAX, |frame| {
self.render(frame.area(), frame.buffer);
})?;
Ok(())
}
_ => Ok(()),
}
}
pub(crate) fn is_done(&self) -> bool {
self.is_done
}
}
#[cfg(test)]
mod tests {
use super::*;
use insta::assert_snapshot;
use std::collections::HashMap;
use std::path::PathBuf;
use std::sync::Arc;
use std::time::Duration;
use crate::history_cell::CommandOutput;
use crate::history_cell::HistoryCell;
use crate::history_cell::PatchEventType;
use crate::history_cell::new_patch_event;
use codex_core::protocol::FileChange;
use codex_protocol::parse_command::ParsedCommand;
use ratatui::Terminal;
use ratatui::backend::TestBackend;
#[derive(Debug)]
struct TestCell {
lines: Vec<Line<'static>>,
}
impl crate::history_cell::HistoryCell for TestCell {
fn display_lines(&self, _width: u16) -> Vec<Line<'static>> {
self.lines.clone()
}
fn transcript_lines(&self) -> Vec<Line<'static>> {
self.lines.clone()
}
}
#[test]
fn edit_prev_hint_is_visible() {
let mut overlay = TranscriptOverlay::new(vec![Arc::new(TestCell {
lines: vec![Line::from("hello")],
})]);
// Render into a small buffer and assert the backtrack hint is present
let area = Rect::new(0, 0, 40, 10);
let mut buf = Buffer::empty(area);
overlay.render(area, &mut buf);
// Flatten buffer to a string and check for the hint text
let mut s = String::new();
for y in area.y..area.bottom() {
for x in area.x..area.right() {
s.push(buf[(x, y)].symbol().chars().next().unwrap_or(' '));
}
s.push('\n');
}
assert!(
s.contains("edit prev"),
"expected 'edit prev' hint in overlay footer, got: {s:?}"
);
}
#[test]
fn transcript_overlay_snapshot_basic() {
// Prepare a transcript overlay with a few lines
let mut overlay = TranscriptOverlay::new(vec![
Arc::new(TestCell {
lines: vec![Line::from("alpha")],
}),
Arc::new(TestCell {
lines: vec![Line::from("beta")],
}),
Arc::new(TestCell {
lines: vec![Line::from("gamma")],
}),
]);
let mut term = Terminal::new(TestBackend::new(40, 10)).expect("term");
term.draw(|f| overlay.render(f.area(), f.buffer_mut()))
.expect("draw");
assert_snapshot!(term.backend());
}
fn buffer_to_text(buf: &Buffer, area: Rect) -> String {
let mut out = String::new();
for y in area.y..area.bottom() {
for x in area.x..area.right() {
let symbol = buf[(x, y)].symbol();
if symbol.is_empty() {
out.push(' ');
} else {
out.push(symbol.chars().next().unwrap_or(' '));
}
}
// Trim trailing spaces for stability.
while out.ends_with(' ') {
out.pop();
}
out.push('\n');
}
out
}
#[test]
fn transcript_overlay_apply_patch_scroll_vt100_clears_previous_page() {
let cwd = PathBuf::from("/repo");
let mut cells: Vec<Arc<dyn HistoryCell>> = Vec::new();
let mut approval_changes = HashMap::new();
approval_changes.insert(
PathBuf::from("foo.txt"),
FileChange::Add {
content: "hello\nworld\n".to_string(),
},
);
let approval_cell: Arc<dyn HistoryCell> = Arc::new(new_patch_event(
PatchEventType::ApprovalRequest,
approval_changes,
&cwd,
));
cells.push(approval_cell);
let mut apply_changes = HashMap::new();
apply_changes.insert(
PathBuf::from("foo.txt"),
FileChange::Add {
content: "hello\nworld\n".to_string(),
},
);
let apply_begin_cell: Arc<dyn HistoryCell> = Arc::new(new_patch_event(
PatchEventType::ApplyBegin {
auto_approved: false,
},
apply_changes,
&cwd,
));
cells.push(apply_begin_cell);
let apply_end_cell: Arc<dyn HistoryCell> =
Arc::new(crate::history_cell::new_user_approval_decision(vec![
"✓ Patch applied".green().bold().into(),
"src/foo.txt".dim().into(),
]));
cells.push(apply_end_cell);
let mut exec_cell = crate::history_cell::new_active_exec_command(
"exec-1".into(),
vec!["bash".into(), "-lc".into(), "ls".into()],
vec![ParsedCommand::Unknown { cmd: "ls".into() }],
);
exec_cell.complete_call(
"exec-1",
CommandOutput {
exit_code: 0,
stdout: "src\nREADME.md\n".into(),
stderr: String::new(),
formatted_output: "src\nREADME.md\n".into(),
},
Duration::from_millis(420),
);
let exec_cell: Arc<dyn HistoryCell> = Arc::new(exec_cell);
cells.push(exec_cell);
let mut overlay = TranscriptOverlay::new(cells);
let area = Rect::new(0, 0, 80, 12);
let mut buf = Buffer::empty(area);
overlay.render(area, &mut buf);
overlay.view.scroll_offset = 0;
overlay.view.wrap_cache = None;
overlay.render(area, &mut buf);
let snapshot = buffer_to_text(&buf, area);
assert_snapshot!("transcript_overlay_apply_patch_scroll_vt100", snapshot);
}
#[test]
fn transcript_overlay_keeps_scroll_pinned_at_bottom() {
let mut overlay = TranscriptOverlay::new(
(0..20)
.map(|i| {
Arc::new(TestCell {
lines: vec![Line::from(format!("line{i}"))],
}) as Arc<dyn HistoryCell>
})
.collect(),
);
let mut term = Terminal::new(TestBackend::new(40, 12)).expect("term");
term.draw(|f| overlay.render(f.area(), f.buffer_mut()))
.expect("draw");
assert!(
overlay.view.is_scrolled_to_bottom(),
"expected initial render to leave view at bottom"
);
overlay.insert_cell(Arc::new(TestCell {
lines: vec!["tail".into()],
}));
assert_eq!(overlay.view.scroll_offset, usize::MAX);
}
#[test]
fn transcript_overlay_preserves_manual_scroll_position() {
let mut overlay = TranscriptOverlay::new(
(0..20)
.map(|i| {
Arc::new(TestCell {
lines: vec![Line::from(format!("line{i}"))],
}) as Arc<dyn HistoryCell>
})
.collect(),
);
let mut term = Terminal::new(TestBackend::new(40, 12)).expect("term");
term.draw(|f| overlay.render(f.area(), f.buffer_mut()))
.expect("draw");
overlay.view.scroll_offset = 0;
overlay.insert_cell(Arc::new(TestCell {
lines: vec!["tail".into()],
}));
assert_eq!(overlay.view.scroll_offset, 0);
}
#[test]
fn static_overlay_snapshot_basic() {
// Prepare a static overlay with a few lines and a title
let mut overlay = StaticOverlay::with_title(
vec!["one".into(), "two".into(), "three".into()],
"S T A T I C".to_string(),
);
let mut term = Terminal::new(TestBackend::new(40, 10)).expect("term");
term.draw(|f| overlay.render(f.area(), f.buffer_mut()))
.expect("draw");
assert_snapshot!(term.backend());
}
#[test]
fn pager_wrap_cache_reuses_for_same_width_and_rebuilds_on_change() {
let long = "This is a long line that should wrap multiple times to ensure non-empty wrapped output.";
let mut pv = PagerView::new(
vec![Text::from(vec![long.into()]), Text::from(vec![long.into()])],
"T".to_string(),
0,
);
// Build cache at width 24
pv.ensure_wrapped(24);
let w1 = pv.cached();
assert!(!w1.is_empty(), "expected wrapped output to be non-empty");
let ptr1 = w1.as_ptr();
// Re-run with same width: cache should be reused (pointer stability heuristic)
pv.ensure_wrapped(24);
let w2 = pv.cached();
let ptr2 = w2.as_ptr();
assert_eq!(ptr1, ptr2, "cache should not rebuild for unchanged width");
// Change width: cache should rebuild and likely produce different length
// Drop immutable borrow before mutating
let prev_len = w2.len();
pv.ensure_wrapped(36);
let w3 = pv.cached();
assert_ne!(
prev_len,
w3.len(),
"wrapped length should change on width change"
);
}
#[test]
fn pager_wrap_cache_invalidates_on_append() {
let long = "Another long line for wrapping behavior verification.";
let mut pv = PagerView::new(vec![Text::from(vec![long.into()])], "T".to_string(), 0);
pv.ensure_wrapped(28);
let w1 = pv.cached();
let len1 = w1.len();
// Append new lines should cause ensure_wrapped to rebuild due to len change
pv.texts.push(Text::from(vec![long.into()]));
pv.texts.push(Text::from(vec![long.into()]));
pv.ensure_wrapped(28);
let w2 = pv.cached();
assert!(
w2.len() >= len1,
"wrapped length should grow or stay same after append"
);
}
}