diff --git a/crates/acp_thread/src/diff.rs b/crates/acp_thread/src/diff.rs
index 9e47e70814b01011afc8b854824ae025b524b3f6..8886b458d623237b74f715d3c1d0def33fbefa7d 100644
--- a/crates/acp_thread/src/diff.rs
+++ b/crates/acp_thread/src/diff.rs
@@ -36,6 +36,7 @@ impl Diff {
                     .log_err();
 
                 buffer.update(cx, |buffer, cx| buffer.set_language(language.clone(), cx));
+                buffer.update(cx, |buffer, _| buffer.parsing_idle()).await;
 
                 let diff = build_buffer_diff(
                     old_text.unwrap_or("".into()).into(),
@@ -287,6 +288,7 @@ impl PendingDiff {
         let buffer_diff = cx.spawn({
             let buffer = buffer.clone();
             async move |_this, cx| {
+                buffer.update(cx, |buffer, _| buffer.parsing_idle()).await;
                 build_buffer_diff(base_text, &buffer, language_registry, cx).await
             }
         });