agent_ui: Insert thread summary as proper mention URI (#40722)

Paweł Kondzior created 4 days ago

This ensures the thread summary is treated as a tracked mention with
accessible context.

Changes:
- Fixed `MessageEditor::insert_thread_summary()` to use proper mention
URI format
- Added test coverage to verify the fix

Release Notes:

- Fixed an issue where "New From Summary" was not properly inserting
thread summaries as contextual mentions when creating new threads.
Thread summaries are now inserted as proper mention URIs.

Change summary

crates/agent_ui/src/acp/message_editor.rs | 100 +++++++++++++++++++++---
1 file changed, 87 insertions(+), 13 deletions(-)

Detailed changes

crates/agent_ui/src/acp/message_editor.rs

@@ -235,8 +235,16 @@ impl MessageEditor {
         window: &mut Window,
         cx: &mut Context<Self>,
     ) {
+        let uri = MentionUri::Thread {
+            id: thread.id.clone(),
+            name: thread.title.to_string(),
+        };
+        let content = format!("{}\n", uri.as_link());
+
+        let content_len = content.len() - 1;
+
         let start = self.editor.update(cx, |editor, cx| {
-            editor.set_text(format!("{}\n", thread.title), window, cx);
+            editor.set_text(content, window, cx);
             editor
                 .buffer()
                 .read(cx)
@@ -245,18 +253,8 @@ impl MessageEditor {
                 .text_anchor
         });
 
-        self.confirm_mention_completion(
-            thread.title.clone(),
-            start,
-            thread.title.len(),
-            MentionUri::Thread {
-                id: thread.id.clone(),
-                name: thread.title.to_string(),
-            },
-            window,
-            cx,
-        )
-        .detach();
+        self.confirm_mention_completion(thread.title, start, content_len, uri, window, cx)
+            .detach();
     }
 
     #[cfg(test)]
@@ -1601,6 +1599,7 @@ mod tests {
     use gpui::{
         AppContext, Entity, EventEmitter, FocusHandle, Focusable, TestAppContext, VisualTestContext,
     };
+    use language_model::LanguageModelRegistry;
     use lsp::{CompletionContext, CompletionTriggerKind};
     use project::{CompletionIntent, Project, ProjectPath};
     use serde_json::json;
@@ -2746,6 +2745,81 @@ mod tests {
             _ => panic!("Expected Text mention for small file"),
         }
     }
+    #[gpui::test]
+    async fn test_insert_thread_summary(cx: &mut TestAppContext) {
+        init_test(cx);
+        cx.update(LanguageModelRegistry::test);
+
+        let fs = FakeFs::new(cx.executor());
+        fs.insert_tree("/project", json!({"file": ""})).await;
+        let project = Project::test(fs, [Path::new(path!("/project"))], cx).await;
+
+        let (workspace, cx) =
+            cx.add_window_view(|window, cx| Workspace::test_new(project.clone(), window, cx));
+
+        let text_thread_store = cx.new(|cx| TextThreadStore::fake(project.clone(), cx));
+        let history_store = cx.new(|cx| HistoryStore::new(text_thread_store, cx));
+
+        // Create a thread metadata to insert as summary
+        let thread_metadata = agent::DbThreadMetadata {
+            id: acp::SessionId("thread-123".into()),
+            title: "Previous Conversation".into(),
+            updated_at: chrono::Utc::now(),
+        };
+
+        let message_editor = cx.update(|window, cx| {
+            cx.new(|cx| {
+                let mut editor = MessageEditor::new(
+                    workspace.downgrade(),
+                    project.clone(),
+                    history_store.clone(),
+                    None,
+                    Default::default(),
+                    Default::default(),
+                    "Test Agent".into(),
+                    "Test",
+                    EditorMode::AutoHeight {
+                        min_lines: 1,
+                        max_lines: None,
+                    },
+                    window,
+                    cx,
+                );
+                editor.insert_thread_summary(thread_metadata.clone(), window, cx);
+                editor
+            })
+        });
+
+        // Construct expected values for verification
+        let expected_uri = MentionUri::Thread {
+            id: thread_metadata.id.clone(),
+            name: thread_metadata.title.to_string(),
+        };
+        let expected_link = format!("[@{}]({})", thread_metadata.title, expected_uri.to_uri());
+
+        message_editor.read_with(cx, |editor, cx| {
+            let text = editor.text(cx);
+
+            assert!(
+                text.contains(&expected_link),
+                "Expected editor text to contain thread mention link.\nExpected substring: {}\nActual text: {}",
+                expected_link,
+                text
+            );
+
+            let mentions = editor.mentions();
+            assert_eq!(
+                mentions.len(),
+                1,
+                "Expected exactly one mention after inserting thread summary"
+            );
+
+            assert!(
+                mentions.contains(&expected_uri),
+                "Expected mentions to contain the thread URI"
+            );
+        });
+    }
 
     #[gpui::test]
     async fn test_whitespace_trimming(cx: &mut TestAppContext) {