From 9746f4f267a5f726fa6dab9992758dee409a736f Mon Sep 17 00:00:00 2001
From: Bennet Bo Fenner <53836821+bennetbo@users.noreply.github.com>
Date: Mon, 29 Apr 2024 15:54:40 +0200
Subject: [PATCH] Fix relative line numbers (#11161)

Closes #11105

Release Notes:

- Fixed rendering of relative line numbers in editor
([#11105](https://github.com/zed-industries/zed/issues/11105)).

Co-authored-by: Thorsten <thorsten@zed.dev>
---
 crates/editor/src/element.rs | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

diff --git a/crates/editor/src/element.rs b/crates/editor/src/element.rs
index c384f13bf0..203f33b44b 100644
--- a/crates/editor/src/element.rs
+++ b/crates/editor/src/element.rs
@@ -1375,7 +1375,7 @@ impl EditorElement {
 
     fn calculate_relative_line_numbers(
         &self,
-        buffer_rows: Vec<Option<u32>>,
+        snapshot: &EditorSnapshot,
         rows: &Range<u32>,
         relative_to: Option<u32>,
     ) -> HashMap<u32, u32> {
@@ -1385,6 +1385,12 @@ impl EditorElement {
         };
 
         let start = rows.start.min(relative_to);
+        let end = rows.end.max(relative_to);
+
+        let buffer_rows = snapshot
+            .buffer_rows(start)
+            .take(1 + (end - start) as usize)
+            .collect::<Vec<_>>();
 
         let head_idx = relative_to - start;
         let mut delta = 1;
@@ -1459,9 +1465,7 @@ impl EditorElement {
             None
         };
 
-        let buffer_rows = buffer_rows.collect::<Vec<_>>();
-        let relative_rows =
-            self.calculate_relative_line_numbers(buffer_rows.clone(), &rows, relative_to);
+        let relative_rows = self.calculate_relative_line_numbers(snapshot, &rows, relative_to);
 
         for (ix, row) in buffer_rows.into_iter().enumerate() {
             let display_row = rows.start + ix as u32;
@@ -4578,8 +4582,12 @@ mod tests {
             .unwrap();
         assert_eq!(layouts.len(), 6);
 
-        let relative_rows =
-            element.calculate_relative_line_numbers((0..6).map(Some).collect(), &(0..6), Some(3));
+        let relative_rows = window
+            .update(cx, |editor, cx| {
+                let snapshot = editor.snapshot(cx);
+                element.calculate_relative_line_numbers(&snapshot, &(0..6), Some(3))
+            })
+            .unwrap();
         assert_eq!(relative_rows[&0], 3);
         assert_eq!(relative_rows[&1], 2);
         assert_eq!(relative_rows[&2], 1);
@@ -4588,16 +4596,24 @@ mod tests {
         assert_eq!(relative_rows[&5], 2);
 
         // works if cursor is before screen
-        let relative_rows =
-            element.calculate_relative_line_numbers((0..6).map(Some).collect(), &(3..6), Some(1));
+        let relative_rows = window
+            .update(cx, |editor, cx| {
+                let snapshot = editor.snapshot(cx);
+                element.calculate_relative_line_numbers(&snapshot, &(3..6), Some(1))
+            })
+            .unwrap();
         assert_eq!(relative_rows.len(), 3);
         assert_eq!(relative_rows[&3], 2);
         assert_eq!(relative_rows[&4], 3);
         assert_eq!(relative_rows[&5], 4);
 
         // works if cursor is after screen
-        let relative_rows =
-            element.calculate_relative_line_numbers((0..6).map(Some).collect(), &(0..3), Some(6));
+        let relative_rows = window
+            .update(cx, |editor, cx| {
+                let snapshot = editor.snapshot(cx);
+                element.calculate_relative_line_numbers(&snapshot, &(0..3), Some(6))
+            })
+            .unwrap();
         assert_eq!(relative_rows.len(), 3);
         assert_eq!(relative_rows[&0], 5);
         assert_eq!(relative_rows[&1], 4);