From cad44088ac4fc149bfbc99a474bf9edfffc4dc1c Mon Sep 17 00:00:00 2001
From: Anthony Eid <anthony@zed.dev>
Date: Tue, 2 Jun 2026 21:27:53 -0400
Subject: [PATCH] Fix mention pasting crash in agent panel

This crash occurred because metion crease were using raw text ranges
that were precomputed before calling editor.edit(), and didn't take into
account that editor normalizes text inserted

The fix is normalizing the text first, then using the normalize text
range for the crease
---
 crates/agent_ui/src/message_editor.rs | 40 ++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/crates/agent_ui/src/message_editor.rs b/crates/agent_ui/src/message_editor.rs
index c6e52939d603d3..69ebf6d0a1c989 100644
--- a/crates/agent_ui/src/message_editor.rs
+++ b/crates/agent_ui/src/message_editor.rs
@@ -36,6 +36,7 @@ use project::{
 use rope::Point;
 use settings::Settings;
 use std::{cmp::min, fmt::Write, ops::Range, rc::Rc, sync::Arc};
+use text::LineEnding;
 use theme_settings::ThemeSettings;
 use ui::{ContextMenu, prelude::*};
 use util::paths::PathStyle;
@@ -1718,11 +1719,15 @@ impl MessageEditor {
         let path_style = workspace.read(cx).project().read(cx).path_style(cx);
         let mut text = String::new();
         let mut mentions = Vec::new();
+        let append_normalized = |text: &mut String, mut segment: String| {
+            LineEnding::normalize(&mut segment);
+            text.push_str(&segment);
+        };
 
         for chunk in message {
             match chunk {
                 acp::ContentBlock::Text(text_content) => {
-                    text.push_str(&text_content.text);
+                    append_normalized(&mut text, text_content.text);
                 }
                 acp::ContentBlock::Resource(acp::EmbeddedResource {
                     resource: acp::EmbeddedResourceResource::TextResourceContents(resource),
@@ -1733,7 +1738,7 @@ impl MessageEditor {
                         continue;
                     };
                     let start = text.len();
-                    write!(&mut text, "{}", mention_uri.as_link()).ok();
+                    append_normalized(&mut text, mention_uri.as_link().to_string());
                     let end = text.len();
                     mentions.push((
                         start..end,
@@ -1749,7 +1754,7 @@ impl MessageEditor {
                         MentionUri::parse(&resource.uri, path_style).log_err()
                     {
                         let start = text.len();
-                        write!(&mut text, "{}", mention_uri.as_link()).ok();
+                        append_normalized(&mut text, mention_uri.as_link().to_string());
                         let end = text.len();
                         mentions.push((start..end, mention_uri, Mention::Link));
                     }
@@ -1775,7 +1780,7 @@ impl MessageEditor {
                         continue;
                     };
                     let start = text.len();
-                    write!(&mut text, "{}", mention_uri.as_link()).ok();
+                    append_normalized(&mut text, mention_uri.as_link().to_string());
                     let end = text.len();
                     mentions.push((
                         start..end,
@@ -5269,6 +5274,33 @@ mod tests {
         assert!(!message_editor.update(cx, |editor, cx| editor.is_empty(cx)));
     }
 
+    #[gpui::test]
+    async fn test_set_message_normalizes_crlf_before_mention(cx: &mut TestAppContext) {
+        init_test(cx);
+        let (message_editor, cx) = setup_message_editor(cx).await;
+
+        message_editor.update_in(cx, |editor, window, cx| {
+            editor.set_message(
+                vec![
+                    acp::ContentBlock::Text(acp::TextContent::new("before\r\n".to_string())),
+                    acp::ContentBlock::ResourceLink(acp::ResourceLink::new(
+                        "file.txt",
+                        "file:///project/file.txt",
+                    )),
+                ],
+                window,
+                cx,
+            );
+        });
+
+        let text = message_editor.update(cx, |editor, cx| editor.text(cx));
+        assert_eq!(text, "before\n[@file.txt](file:///project/file.txt)");
+
+        let mention_uris =
+            message_editor.update(cx, |editor, cx| editor.mention_set.read(cx).mentions());
+        assert_eq!(mention_uris.len(), 1);
+    }
+
     #[gpui::test]
     async fn test_set_message_replaces_existing_content(cx: &mut TestAppContext) {
         init_test(cx);