Wrap lines config option

src/config.rs

@@ -60,6 +60,7 @@ pub struct GeneralConfig {
     pub log_author_width: usize,
     pub mouse_support: bool,
     pub mouse_scroll_lines: usize,
+    pub wrap_lines: bool,
 }
 
 #[derive(Default, Debug, Deserialize)]

src/default_config.toml

@@ -14,6 +14,9 @@ recent_commits_limit = 10
 log_author_width = 15
 mouse_support = false
 mouse_scroll_lines = 3
+# Wrap lines that are wider than the screen. When disabled, they are cut off
+# at the right edge instead.
+wrap_lines = true
 
 # When to prompt for discard confirmation. Options:
 # "line"  - always prompt even for individual lines (default),

src/screen/mod.rs

@@ -940,7 +940,7 @@ fn layout_item<'a>(layout: &mut UiTree<'a>, screen: &'a Screen, hide_cursor: boo
     let line_sel = line_selection_highlight(style, &line, is_line_sel);
     let bg = area_sel.patch(line_sel);
 
-    layout.row_with(bg, opts().fill_x(), |layout| {
+    layout.row_with(bg, ui::item::row_opts(&screen.config), |layout| {
         let gutter_char = if !hide_cursor && line.highlighted {
             gutter_char(style, is_line_sel, bg)
         } else {

src/tests/mod.rs

@@ -158,6 +158,24 @@ fn recent_commits_with_limit() {
     snapshot!(ctx, "");
 }
 
+const LONG_SUMMARY: &str =
+    "a commit summary that is far too wide to fit within eighty columns of terminal";
+
+#[test]
+fn long_lines_wrap_by_default() {
+    let ctx = setup_clone!();
+    commit(&ctx.dir, LONG_SUMMARY, "testing\n");
+    snapshot!(ctx, "");
+}
+
+#[test]
+fn long_lines_are_cut_off_with_wrap_lines_disabled() {
+    let mut ctx = setup_clone!();
+    ctx.config().general.wrap_lines = false;
+    commit(&ctx.dir, LONG_SUMMARY, "testing\n");
+    snapshot!(ctx, "");
+}
+
 #[test]
 fn log() {
     let ctx = setup_clone!();

src/tests/snapshots/gitu__tests__long_lines_are_cut_off_with_wrap_lines_disabled.snap

@@ -0,0 +1,25 @@
+---
+source: src/tests/mod.rs
+expression: ctx.redact_buffer()
+---
+▌On branch main                                                                 |
+▌Your branch is ahead of 'origin/main' by 1 commit(s).                          |
+                                                                                |
+ Recent commits                                                                 |
+ ac66c1a main add a commit summary that is far too wide to fit w Author Name __ |
+ b66a0bf origin/main add initial-file                            Author Name __ |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+styles_hash: b2801eef61626397

src/tests/snapshots/gitu__tests__long_lines_wrap_by_default.snap

@@ -0,0 +1,25 @@
+---
+source: src/tests/mod.rs
+expression: ctx.redact_buffer()
+---
+▌On branch main                                                                 |
+▌Your branch is ahead of 'origin/main' by 1 commit(s).                          |
+                                                                                |
+ Recent commits                                                                 |
+ ac66c1a main add a commit summary that is far too wide to fit   Author Name __ |
+        within eighty columns of terminal                                       |
+ b66a0bf origin/main add initial-file                            Author Name __ |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+                                                                                |
+styles_hash: 70b38ef10efcdd9f

src/ui.rs

@@ -293,7 +293,13 @@ fn print_spans(
             Payload::Leaf(span) => {
                 blank_until(term, &mut at, pos, size.0, bg, bg_end)?;
                 term.queue_move_cursor(pos[0], pos[1])?;
-                print_span(term, span, highlight.within(index), highlight.style)?;
+                print_span(
+                    term,
+                    span,
+                    item_size[0],
+                    highlight.within(index),
+                    highlight.style,
+                )?;
 
                 at[0] = pos[0].saturating_add(item_size[0]);
             }
@@ -307,15 +313,21 @@ fn print_spans(
     Ok(())
 }
 
+/// Prints at most `width` columns of the span, which is less than its text
+/// when the layout cut it off at an edge.
 fn print_span(
     term: &mut TermBackend,
     Span(text, style): &Span,
+    width: u16,
     matches: impl Iterator<Item = Range<usize>>,
     match_style: Style,
 ) -> Result<(), Error> {
+    let text = clip(text, width as usize);
     let mut at = 0;
 
     for matched in matches {
+        let matched = matched.start.min(text.len())..matched.end.min(text.len());
+
         if at < matched.start {
             term.queue_print(&text[at..matched.start], style)?;
         }
@@ -331,6 +343,21 @@ fn print_span(
     Ok(())
 }
 
+/// The longest prefix of `text` that fits in `width` columns.
+fn clip(text: &str, width: usize) -> &str {
+    let mut used = 0;
+
+    for (i, grapheme) in text.grapheme_indices(true) {
+        used += UnicodeWidthStr::width(grapheme);
+
+        if used > width {
+            return &text[..i];
+        }
+    }
+
+    text
+}
+
 fn blank_until(
     term: &mut TermBackend,
     at: &mut [u16; 2],
@@ -404,6 +431,15 @@ mod tests {
             .collect()
     }
 
+    #[test]
+    fn clip_stops_before_a_grapheme_that_does_not_fit() {
+        assert_eq!("abc", clip("abcdef", 3));
+        assert_eq!("abcdef", clip("abcdef", 10));
+        // A double-width char that only half fits is left out entirely.
+        assert_eq!("a", clip("a漢", 2));
+        assert_eq!("", clip("漢", 1));
+    }
+
     #[test]
     fn a_match_may_run_from_one_span_into_the_next() {
         assert_eq!(

src/ui/item.rs

@@ -7,11 +7,20 @@ use crate::gitu_diff::Status;
 use crate::highlight;
 use crate::item_data::{ItemData, Ref, SectionHeader};
 use crate::items::Item;
-use crate::ui::layout::opts;
+use crate::ui::layout::{Opts, opts};
 use crate::ui::{UiTree, layout_span};
 use unicode_segmentation::UnicodeSegmentation;
 use unicode_width::UnicodeWidthStr;
 
+/// Options for a row holding an item, honouring `general.wrap_lines`.
+pub(crate) fn row_opts(config: &Config) -> Opts<u16> {
+    if config.general.wrap_lines {
+        opts().fill_x()
+    } else {
+        opts().fill_x().no_wrap()
+    }
+}
+
 /// Lays out an [`Item`] as spans in the caller's container, which is expected to
 /// be a single row.
 ///
@@ -78,7 +87,7 @@ pub(crate) fn layout_item<'a>(
                 ),
             );
 
-            layout.row(opts().fill_x(), |layout| {
+            layout.row(row_opts(config), |layout| {
                 for reference in associated_references {
                     layout_span(layout, (" ".into(), base));
                     layout_reference(layout, reference, config, base);

src/ui/layout/node.rs

@@ -67,7 +67,8 @@ impl<U: Scalar> Opts<U> {
         }
     }
 
-    #[allow(dead_code)]
+    /// Cuts a child that doesn't fit off at the edge, rather than starting a
+    /// new line.
     pub fn no_wrap(self) -> Self {
         Self {
             wrap: Some(false),