From 4b0f5eb6a825578b43a8605ed07e9981009e70aa Mon Sep 17 00:00:00 2001
From: Jeremy Rose <172423086+nornagon-openai@users.noreply.github.com>
Date: Tue, 7 Oct 2025 11:32:13 -0700
Subject: [PATCH] tui: wrapping bugfix (#4674)

this fixes an issue where text lines with long words would sometimes
overflow.

- the default penalties for the OptimalFit algorithm allow overflowing
in some cases. this seems insane to me, and i considered just banning
the OptimalFit algorithm by disabling the 'smawk' feature on textwrap,
but decided to keep it and just bump the overflow penalty to ~infinity
since optimal fit does sometimes produce nicer wrappings. it's not clear
this is worth it, though, and maybe we should just dump the optimal fit
algorithm completely.
- user history messages weren't rendering with the same wrap algorithm
as used in the composer, which sometimes resulted in wrapping messages
differently in the history vs. in the composer.
---
 codex-rs/tui/src/history_cell.rs | 3 ++-
 codex-rs/tui/src/wrapping.rs     | 7 ++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/codex-rs/tui/src/history_cell.rs b/codex-rs/tui/src/history_cell.rs
index e3a89da3..61640c33 100644
--- a/codex-rs/tui/src/history_cell.rs
+++ b/codex-rs/tui/src/history_cell.rs
@@ -104,7 +104,8 @@ impl HistoryCell for UserHistoryCell {
                 .lines()
                 .map(|l| Line::from(l).style(style))
                 .collect::<Vec<_>>(),
-            RtOptions::new(wrap_width as usize),
+            // Wrap algorithm matches textarea.rs.
+            RtOptions::new(wrap_width as usize).wrap_algorithm(textwrap::WrapAlgorithm::FirstFit),
         );
 
         lines.push(Line::from("").style(style));
diff --git a/codex-rs/tui/src/wrapping.rs b/codex-rs/tui/src/wrapping.rs
index da79f036..70ca2e46 100644
--- a/codex-rs/tui/src/wrapping.rs
+++ b/codex-rs/tui/src/wrapping.rs
@@ -2,6 +2,7 @@ use ratatui::text::Line;
 use ratatui::text::Span;
 use std::ops::Range;
 use textwrap::Options;
+use textwrap::wrap_algorithms::Penalties;
 
 use crate::render::line_utils::push_owned_lines;
 
@@ -90,7 +91,11 @@ impl<'a> RtOptions<'a> {
             subsequent_indent: Line::default(),
             break_words: true,
             word_separator: textwrap::WordSeparator::new(),
-            wrap_algorithm: textwrap::WrapAlgorithm::new(),
+            wrap_algorithm: textwrap::WrapAlgorithm::OptimalFit(Penalties {
+                // ~infinite overflow penalty, we never want to overflow a line.
+                overflow_penalty: usize::MAX / 4,
+                ..Default::default()
+            }),
             word_splitter: textwrap::WordSplitter::HyphenSplitter,
         }
     }