[feat] crude version of line wrapping implemented

build.zig

@@ -58,7 +58,7 @@ pub fn build(b: *std.Build) void {
     build_options.addOption(
         usize,
         "expected_package_root_test_count",
-        if (!provider_enabled and test_filters.len == 0) 1988 else 0,
+        if (!provider_enabled and test_filters.len == 0) 2000 else 0,
     );
     const build_options_mod = build_options.createModule();
 

docs/guide.md

@@ -114,6 +114,34 @@ available for source selections in side-by-side mode and includes the
 before/after commit IDs and the selected side. Unified diff selections use
 diff text. Without a selection, `Y` in a diff pane copies the current hunk.
 
+### Wrap long lines
+
+Press `W` to toggle line wrapping in the Changes, History, or Compare diff
+view, or in Repository source text. Diff wrapping works in unified and
+side-by-side layouts, including the unified layout used in narrow terminals.
+Help (`?`) shows the effective key if you remap `toggle_line_wrap`.
+
+Wrapping starts off. Each page keeps its own choice while its viewer is
+retained, including file changes, reloads, and switching away and back. A
+newly created viewer starts with wrapping off; Repository also resets it
+when switching repositories. The choice is not saved
+across restarts. With wrapping off, long lines are clipped and you can
+scroll horizontally with the left/right arrows.
+
+With wrapping on, continuation rows repeat neither line numbers nor diff
+markers. Use the mouse wheel, Page Up/Down, or Ctrl+u/d/b/f to read long
+wrapped lines. `j` / `k` still move between original source rows. Diff search
+moves by original row and reveals its first fragment; scroll down to read a
+match farther along that row. Repository search retains each matching
+occurrence, including multiple matches on one line, and reveals the matching
+fragment. Selection and copying use the original text,
+without inserting newlines at wrap boundaries.
+
+Tabs retain their spacing across wrap boundaries. If a character cannot
+fit even on an empty row, a replacement glyph is shown so scrolling can
+continue; copying still preserves the original character. A pane with no
+room for text shows no fragments and restores them when widened.
+
 ### Switch repositories and branches
 
 Press `R` from any working view to open the repository picker. Select a

src/app/diff_surface.zig

@@ -55,10 +55,43 @@ pub const SelectionCompletionPolicy = enum {
 
 pub const ViewOptions = struct {
     line_numbers: bool = true,
+    line_wrap: bool = false,
 
     pub fn toggleLineNumbers(self: *ViewOptions) void {
         self.line_numbers = !self.line_numbers;
     }
+
+    pub fn toggleLineWrap(self: *ViewOptions) void {
+        self.line_wrap = !self.line_wrap;
+    }
+};
+
+/// One position: OFF and ordinary rows have no independently mutable wrap state.
+pub const ViewportPosition = union(enum) {
+    logical: usize,
+    wrapped: struct {
+        row: usize,
+        target: ?context.SelectedTarget,
+        content: ContentToken,
+        anchor: WrapAnchor,
+    },
+
+    pub fn atRow(value: usize) ViewportPosition {
+        return .{ .logical = value };
+    }
+
+    pub fn row(self: ViewportPosition) usize {
+        return switch (self) {
+            .logical => |value| value,
+            .wrapped => |value| value.row,
+        };
+    }
+};
+
+pub const WrapAnchor = struct {
+    side: ?diff_selection.Side = null,
+    byte: usize = 0,
+    tab_cell: usize = 0,
 };
 
 pub const ViewerState = struct {
@@ -73,7 +106,7 @@ pub const ViewerState = struct {
     sidebar_hidden: bool = false,
     sidebar_width: ?u16 = null,
     sidebar_horizontal_scroll: usize = 0,
-    diff_scroll: usize = 0,
+    diff_scroll: ViewportPosition = .{ .logical = 0 },
     diff_horizontal_scroll: usize = 0,
     diff_cursor: diff_view_model.BodyCoordinate = .{ .metadata = 0 },
     display_mode: diff_render.DisplayMode = .side_by_side,
@@ -100,8 +133,8 @@ pub const ReloadAnchor = struct {
     visible_sidebar_row: usize,
     diff_cursor: diff_view_model.BodyCoordinate,
     diff_cursor_offset: ?usize,
-    diff_scroll: usize,
-    selection_viewport: ?selection_action.SelectionViewportAnchor = null,
+    diff_scroll: ViewportPosition,
+    selection_viewport: ?navigation.ViewportAnchor = null,
     diff_horizontal_scroll: usize,
     sidebar_horizontal_scroll: usize,
     search_coordinate: ?diff_view_model.BodyCoordinate,
@@ -151,7 +184,7 @@ pub const DisplayNavigationSnapshot = struct {
     selected_target: ?context.SelectedTarget,
     selected_node: usize,
     diff_cursor: diff_view_model.BodyCoordinate,
-    diff_scroll: usize,
+    diff_scroll: ViewportPosition,
     diff_horizontal_scroll: usize,
     sidebar_horizontal_scroll: usize,
     search_coordinate: ?diff_view_model.BodyCoordinate,

src/app/diff_surface/body_resolver.zig

@@ -99,9 +99,11 @@ pub const RenderProjectedBodyArgs = struct {
     requested_mode: diff_render.DisplayMode,
     display_mode_toggle_key: ?[]const u8 = null,
     scroll: usize,
+    wrap_start: usize = 0,
     horizontal_scroll: usize,
     pane_active: bool,
     line_numbers: bool,
+    line_wrap: bool = false,
     highlighted_hunk: ?usize,
     cursor_offset: ?usize,
     palette: theme.Palette,
@@ -414,6 +416,7 @@ test "body resolver forwards render arguments and propagates renderer errors" {
         .horizontal_scroll = 11,
         .pane_active = false,
         .line_numbers = false,
+        .line_wrap = false,
         .highlighted_hunk = 13,
         .cursor_offset = 17,
         .palette = .default(),

src/app/diff_surface/message.zig

@@ -84,4 +84,5 @@ pub const Msg = union(enum) {
     increase_sidebar_width,
     toggle_display_mode,
     toggle_line_numbers,
+    toggle_line_wrap,
 };