tailcallhq · tusharmath · Oct 1, 2025 · Oct 1, 2025 · Oct 1, 2025 · Oct 1, 2025
diff --git a/crates/forge_app/src/fmt/snapshots/forge_app__fmt__fmt_output__tests__fs_patch_success.snap b/crates/forge_app/src/fmt/snapshots/forge_app__fmt__fmt_output__tests__fs_patch_success.snap
@@ -2,8 +2,8 @@
 source: crates/forge_app/src/fmt/fmt_output.rs
 expression: actual
 ---
-1        |-Hello world
-2        |-This is a test
-    1    |+Hello universe
-    2    |+This is a test
-    3    |+New line
+1   |-Hello world
+2   |-This is a test
+  1 |+Hello universe
+  2 |+This is a test
+  3 |+New line
diff --git a/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_create_overwrite.snap b/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_create_overwrite.snap
@@ -6,7 +6,7 @@ expression: to_value(actual)
   path="/home/user/existing_file.txt"
   total_lines="1"
 >
-<file_diff><![CDATA[1        |-Old content
-    1    |+New content for the file
+<file_diff><![CDATA[1   |-Old content
+  1 |+New content for the file
 ]]></file_diff>
 </file_overwritten>
diff --git a/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_patch_basic.snap b/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_patch_basic.snap
@@ -5,8 +5,8 @@ expression: to_value(actual)
 <file_diff
   path="/home/user/test.txt"
   total_lines="2"
-><![CDATA[1        |-Hello world
-    1    |+Hello universe
-2   2    | This is a test
+><![CDATA[1   |-Hello world
+  1 |+Hello universe
+2 2 | This is a test
 ]]>
 </file_diff>
diff --git a/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_patch_with_warning.snap b/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_patch_with_warning.snap
@@ -5,9 +5,9 @@ expression: to_value(actual)
 <file_diff
   path="/home/user/large_file.txt"
   total_lines="3"
-><![CDATA[1   1    | line1
-    2    |+new line
-2   3    | line2
+><![CDATA[1 1 | line1
+  2 |+new line
+2 3 | line2
 ]]>
 <warning>Large file modification</warning>
 </file_diff>
diff --git a/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_undo_file_restored.snap b/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_undo_file_restored.snap
@@ -5,9 +5,9 @@ expression: to_value(actual)
 <file_undo
   path="/home/user/restored_file.txt"
   status="restored"
-><![CDATA[1        |-Original content
-2        |-Before changes
-    1    |+Modified content
-    2    |+After restoration
+><![CDATA[1   |-Original content
+2   |-Before changes
+  1 |+Modified content
+  2 |+After restoration
 ]]>
 </file_undo>
diff --git a/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_undo_success.snap b/crates/forge_app/src/snapshots/forge_app__operation__tests__fs_undo_success.snap
@@ -5,7 +5,7 @@ expression: to_value(actual)
 <file_undo
   path="/home/user/test.txt"
   status="restored"
-><![CDATA[1        |-ABC
-    1    |+PQR
+><![CDATA[1   |-ABC
+  1 |+PQR
 ]]>
 </file_undo>
diff --git a/crates/forge_display/src/diff.rs b/crates/forge_display/src/diff.rs
@@ -3,13 +3,22 @@ use std::fmt;
 use console::{Style, style};
 use similar::{ChangeTag, TextDiff};
 
-struct Line(Option<usize>);
+struct Line {
+    index: Option<usize>,
+    width: usize,
+}
+
+impl Line {
+    fn new(index: Option<usize>, width: usize) -> Self {
+        Self { index, width }
+    }
+}
 
 impl fmt::Display for Line {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self.0 {
-            None => write!(f, "    "),
-            Some(idx) => write!(f, "{:<4}", idx + 1),
+        match self.index {
+            None => write!(f, "{:width$}", "", width = self.width),
+            Some(idx) => write!(f, "{:<width$}", idx + 1, width = self.width),
         }
     }
 }
@@ -52,6 +61,28 @@ impl DiffFormat {
             return DiffResult { result: output, lines_added, lines_removed };
         }
 
+        // First pass: Calculate dynamic width based on max line numbers in actual
+        // changes
+        let mut max_line_number = 0;
+        for group in &ops {
+            for op in group {
+                for change in diff.iter_inline_changes(op) {
+                    if let Some(old_idx) = change.old_index() {
+                        max_line_number = max_line_number.max(old_idx + 1);
+                    }
+                    if let Some(new_idx) = change.new_index() {
+                        max_line_number = max_line_number.max(new_idx + 1);
+                    }
+                }
+            }
+        }
+        let width = if max_line_number == 0 {
+            1
+        } else {
+            (max_line_number as f64).log10().floor() as usize + 1
+        };
+
+        // Second pass: Format the output
         for (idx, group) in ops.iter().enumerate() {
             if idx > 0 {
                 output.push_str(&format!("{}\n", style("...").dim()));
@@ -71,9 +102,9 @@ impl DiffFormat {
                     };
 
                     output.push_str(&format!(
-                        "{}{} |{}",
-                        style(Line(change.old_index())).dim(),
-                        style(Line(change.new_index())).dim(),
+                        "{} {} |{}",
+                        style(Line::new(change.old_index(), width)).dim(),
+                        style(Line::new(change.new_index(), width)).dim(),
                         s.apply_to(sign),
                     ));
 
@@ -139,4 +170,45 @@ mod tests {
         assert_eq!(diff.lines_removed(), 1);
         assert_snapshot!(clean_diff);
     }
+
+    #[test]
+    fn test_dynamic_width_with_large_line_numbers() {
+        // Test with 100+ lines to verify width calculation
+        let old_lines = (1..=150).map(|i| format!("line {}", i)).collect::<Vec<_>>();
+        let mut new_lines = old_lines.clone();
+        new_lines[99] = "modified line 100".to_string();
+
+        let old = old_lines.join("\n");
+        let new = new_lines.join("\n");
+        let diff = DiffFormat::format(&old, &new);
+        let clean_diff = strip_ansi_codes(&diff.diff());
+
+        // With 150 lines, width should be 3 (for numbers like "100")
+        // Verify the format includes proper spacing
+        assert!(clean_diff.contains("100"));
+        assert_eq!(diff.lines_added(), 1);
+    }
+
+    #[test]
+    fn test_width_based_on_diff_not_file_size() {
+        // Large file but diff only at the beginning
+        let old_lines = (1..=1000)
+            .map(|i| format!("line {}", i))
+            .collect::<Vec<_>>();
+        let mut new_lines = old_lines.clone();
+        new_lines[4] = "modified line 5".to_string(); // Only change line 5
+
+        let old = old_lines.join("\n");
+        let new = new_lines.join("\n");
+        let diff = DiffFormat::format(&old, &new);
+        let clean_diff = strip_ansi_codes(&diff.diff());
+
+        // Diff only shows lines 3-8 (context), so width should be 1 (for single digit
+        // numbers) NOT 4 (which would be needed for line 1000)
+        assert!(clean_diff.contains("3 3 | line 3"));
+        assert!(clean_diff.contains("5   |-line 5"));
+        assert_eq!(diff.lines_added(), 1);
+        assert_eq!(diff.lines_removed(), 1);
+        assert_snapshot!(clean_diff);
+    }
 }
diff --git a/crates/forge_display/src/snapshots/forge_display__diff__tests__diff_printer_simple_diff.snap b/crates/forge_display/src/snapshots/forge_display__diff__tests__diff_printer_simple_diff.snap
@@ -2,9 +2,9 @@
 source: crates/forge_display/src/diff.rs
 expression: clean_diff
 ---
-1   1    | line 1
-2        |-line 2
-    2    |+modified line
-3   3    | line 3
-4   4    | line 5
-5   5    | line 6
+1 1 | line 1
+2   |-line 2
+  2 |+modified line
+3 3 | line 3
+4 4 | line 5
+5 5 | line 6
diff --git a/crates/forge_display/src/snapshots/forge_display__diff__tests__file_source.snap b/crates/forge_display/src/snapshots/forge_display__diff__tests__file_source.snap
@@ -2,9 +2,9 @@
 source: crates/forge_display/src/diff.rs
 expression: clean_diff
 ---
-1   1    | line 1
-2   2    | line 2
-3        |-line 3
-4        |-line 4
-5        |-line 5
-    3    |+line 3
+1 1 | line 1
+2 2 | line 2
+3   |-line 3
+4   |-line 4
+5   |-line 5
+  3 |+line 3
diff --git a/..._display/src/snapshots/forge_display__diff__tests__width_based_on_diff_not_file_size.snap b/..._display/src/snapshots/forge_display__diff__tests__width_based_on_diff_not_file_size.snap
@@ -0,0 +1,12 @@
+---
+source: crates/forge_display/src/diff.rs
+expression: clean_diff
+---
+2 2 | line 2
+3 3 | line 3
+4 4 | line 4
+5   |-line 5
+  5 |+modified line 5
+6 6 | line 6
+7 7 | line 7
+8 8 | line 8