Panic during drawing a calendar

[pskrgag]

Reproduces on current HEAD (54b06cd).

Steps to reproduce:

1. Run taskwarrior-tui
2. Press [ 2 times
3. App panics

Backtrace:

Backtrace (most recent call first):
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/buffer/buffer.rs", line 137, in ratatui::buffer::buffer::Buffer::index_of
    debug_assert!(
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/buffer/buffer.rs", line 105, in ratatui::buffer::buffer::Buffer::get_mut
    let i = self.index_of(x, y);
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/buffer/buffer.rs", line 221, in ratatui::buffer::buffer::Buffer::set_stringn
    self.get_mut(x, y).set_symbol(symbol).set_style(style);
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/buffer/buffer.rs", line 191, in ratatui::buffer::buffer::Buffer::set_string
    self.set_stringn(x, y, string, usize::MAX, style);
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/calendar.rs", line 208, in <taskwarrior_tui::calendar::Calendar as ratatui::widgets::Widget>::render
    buf.set_string(x, y, s, style);
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/terminal/frame.rs", line 75, in ratatui::terminal::frame::Frame::render_widget
    widget.render(area, self.buffer);
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/app.rs", line 530, in taskwarrior_tui::app::TaskwarriorTui::draw_calendar
    f.render_widget(c, layout);
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/app.rs", line 454, in taskwarrior_tui::app::TaskwarriorTui::draw
    Mode::Calendar => self.draw_calendar(f, main_layout),
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/app.rs", line 383, in taskwarrior_tui::app::TaskwarriorTui::run::{{closure}}::{{closure}}
    terminal.draw(|f| self.draw(f))?;
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/terminal/terminal.rs", line 269, in ratatui::terminal::terminal::Terminal<B>::draw
    f(&mut frame);
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/app.rs", line 383, in taskwarrior_tui::app::TaskwarriorTui::run::{{closure}}
    terminal.draw(|f| self.draw(f))?;
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/main.rs", line 117, in taskwarrior_tui::tui_main::{{closure}}
    let r = app.run(&mut terminal).await;
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/main.rs", line 187, in taskwarrior_tui::main::{{closure}}
    .block_on(async { tui_main(report).await });
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/park.rs", line 281, in tokio::runtime::park::CachedParkThread::block_on::{{closure}}
    if let Ready(v) = crate::runtime::coop::budget(|| f.as_mut().poll(&mut cx)) {
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/coop.rs", line 107, in tokio::runtime::coop::with_budget
    f()
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/coop.rs", line 73, in tokio::runtime::coop::budget
    with_budget(Budget::initial(), f)
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/park.rs", line 281, in tokio::runtime::park::CachedParkThread::block_on
    if let Ready(v) = crate::runtime::coop::budget(|| f.as_mut().poll(&mut cx)) {
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/context/blocking.rs", line 66, in tokio::runtime::context::blocking::BlockingRegionGuard::block_on
    park.block_on(f)
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/scheduler/multi_thread/mod.rs", line 87, in tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}}
    blocking.block_on(future).expect("failed to park thread")
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/context/runtime.rs", line 65, in tokio::runtime::context::runtime::enter_runtime
    return f(&mut guard.blocking);
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/scheduler/multi_thread/mod.rs", line 86, in tokio::runtime::scheduler::multi_thread::MultiThread::block_on
    crate::runtime::context::enter_runtime(handle, true, |blocking| {
  File "/home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.38.0/src/runtime/runtime.rs", line 349, in tokio::runtime::runtime::Runtime::block_on
    Scheduler::MultiThread(exec) => exec.block_on(&self.handle.inner, future),
  File "/home/paskripkin/Documents/git/taskwarrior-tui/src/main.rs", line 184, in taskwarrior_tui::main
    let r = tokio::runtime::Builder::new_multi_thread()

The application panicked (crashed).
  Trying to access position outside the buffer: x=38, y=77, area=Rect { x: 0, y: 0, width: 165, height: 77 }
in /home/paskripkin/.cargo/registry/src/index.crates.io-6f17d22bba15001f/ratatui-0.26.3/src/buffer/buffer.rs, line 221
thread: main

Sort of analysis

Code panics here, since y > area.height

            if d.1 == Local::now().date_naive() {
              buf.set_string(x, y, s, self.today_style);
            } else {
              buf.set_string(x, y, s, style); <-- here
            }

Simple fix like:

--- a/src/calendar.rs
+++ b/src/calendar.rs
@@ -212,7 +212,7 @@ impl<'a> Widget for Calendar<'a> {
           moredays |= d.0.month() == d.1.month() || d.1 < d.0;
         }
         y += 1;
-        if !moredays {
+        if !moredays || y >= area.height {
           break;
         }
       }

fixes for me, but I am not sure if it's complete fix, since code is kinda not straightforward.