Simplify incrementing of line numbers

3 files changed, 10 insertions, 28 deletions

diff --git a/src/features/line_numbers.rs b/src/features/line_numbers.rs
index 56cb3daa..3afce6b1 100644
--- a/src/features/line_numbers.rs
+++ b/src/features/line_numbers.rs
@@ -66,6 +66,7 @@ pub fn linenumbers_and_styles<'a>(
     line_numbers_data: &'a mut LineNumbersData,
     state: &State,
     config: &'a config::Config,
+    increment: bool,
 ) -> Option<(MinusPlus<Option<usize>>, MinusPlus<Style>)> {
     let nr_left = line_numbers_data.line_number[Left];
     let nr_right = line_numbers_data.line_number[Right];
@@ -76,18 +77,18 @@ pub fn linenumbers_and_styles<'a>(
     );
     let ((minus_number, plus_number), (minus_style, plus_style)) = match state {
         State::HunkMinus(_) => {
-            line_numbers_data.line_number[Left] += 1;
+            line_numbers_data.line_number[Left] += increment as usize;
             ((Some(nr_left), None), (minus_style, plus_style))
         }
         State::HunkMinusWrapped => ((None, None), (minus_style, plus_style)),
         State::HunkZero => {
-            line_numbers_data.line_number[Left] += 1;
-            line_numbers_data.line_number[Right] += 1;
+            line_numbers_data.line_number[Left] += increment as usize;
+            line_numbers_data.line_number[Right] += increment as usize;
             ((Some(nr_left), Some(nr_right)), (zero_style, zero_style))
         }
         State::HunkZeroWrapped => ((None, None), (zero_style, zero_style)),
         State::HunkPlus(_) => {
-            line_numbers_data.line_number[Right] += 1;
+            line_numbers_data.line_number[Right] += increment as usize;
             ((None, Some(nr_right)), (minus_style, plus_style))
         }
         State::HunkPlusWrapped => ((None, None), (minus_style, plus_style)),
diff --git a/src/features/side_by_side.rs b/src/features/side_by_side.rs
index 1485254c..b052f97c 100644
--- a/src/features/side_by_side.rs
+++ b/src/features/side_by_side.rs
@@ -197,15 +197,6 @@ pub fn paint_zero_lines_side_by_side<'a>(
                 config,
             );
             output_buffer.push_str(&panel_line);
-
-            if *panel_side == Left && state != State::HunkZeroWrapped {
-                // TODO: Avoid doing the superimpose_style_sections work twice.
-                // HACK: These are getting incremented twice, so knock them back down once.
-                if let Some(d) = line_numbers_data.as_mut() {
-                    d.line_number[Left] -= 1;
-                    d.line_number[Right] -= 1;
-                }
-            }
         }
         output_buffer.push('\n');
     }
@@ -386,21 +377,6 @@ fn paint_minus_or_plus_panel_line<'a>(
         config,
     );
 
-    // Knock back down spuriously incremented line numbers. See comment above.
-    match (state, &state_for_line_numbers_field) {
-        (s, t) if s == t => {}
-        (State::HunkPlus(_), State::HunkMinus(_)) => {
-            if let Some(d) = line_numbers_data.as_mut() {
-                d.line_number[Left] -= 1;
-            }
-        }
-        (State::HunkMinus(_), State::HunkPlus(_)) => {
-            if let Some(d) = line_numbers_data.as_mut() {
-                d.line_number[Right] -= 1;
-            }
-        }
-        _ => unreachable!(),
-    }
     (line, line_is_empty)
 }
 
diff --git a/src/paint.rs b/src/paint.rs
index bcf3e941..2be015e3 100644
--- a/src/paint.rs
+++ b/src/paint.rs
@@ -532,10 +532,15 @@ impl<'a> Painter<'a> {
 
         let output_line_numbers = config.line_numbers && line_numbers_data.is_some();
         if output_line_numbers {
+            // Unified diff lines are printed in one go, but side-by-side lines
+            // are printed in two parts, so do not increment line numbers when the
+            // first (left) part is printed.
+            let increment = !matches!(side_by_side_panel, Some(side_by_side::Left));
             if let Some((line_numbers, styles)) = line_numbers::linenumbers_and_styles(
                 line_numbers_data.as_mut().unwrap(),
                 state,
                 config,
+                increment,
             ) {
                 ansi_strings.extend(line_numbers::format_and_paint_line_numbers(
                     line_numbers_data.as_ref().unwrap(),