fix(sandbox): publish empty diff snapshots to clear stale views

crates/sandbox-core/CHANGELOG.md

@@ -1,3 +1,9 @@
+## Unreleased
+
+### Fixes
+
+- Send empty sandbox diff snapshots after the final change is removed, clearing stale diff views.
+
 
 
 ## v0.1.0 (2026-09-03)

crates/sandbox-core/src/server.rs

@@ -1788,7 +1788,7 @@ async fn push_diff_view<B: SandboxBackend, M: MetadataStore, C: CallbackClient>(
     };
 
     let files: Vec<serde_json::Value> = match &repo_state.mode {
-        SandboxMode::Direct => Vec::new(),
+        SandboxMode::Direct => return,
         _ => {
             let Ok(changed) = state.backend.diff_files(sandbox_dir, &repo_state).await else {
                 return;
@@ -1807,16 +1807,14 @@ async fn push_diff_view<B: SandboxBackend, M: MetadataStore, C: CallbackClient>(
         }
     };
 
-    if !files.is_empty() {
-        rap_protocol::send_view_update(
-            &state.callback_client,
-            &invocation.callback_url,
-            invocation.group_id.clone(),
-            "diff",
-            serde_json::json!({ "files": files }),
-        )
-        .await;
-    }
+    rap_protocol::send_view_update(
+        &state.callback_client,
+        &invocation.callback_url,
+        invocation.group_id.clone(),
+        "diff",
+        serde_json::json!({ "files": files }),
+    )
+    .await;
 }
 
 /// Build a pretty-printed unified diff for display in the CLI.

crates/sandbox-local/tests/execute_command.rs

@@ -234,3 +234,50 @@ async fn sandboxed_command_can_write_sccache_cache_dir() {
         std::env::remove_var("SCCACHE_DIR");
     }
 }
+
+#[tokio::test]
+async fn deleting_last_added_file_clears_diff_view() {
+    let repo = jj_init_with_file("README.md", "hello\n");
+    let metadata = tempfile::tempdir().expect("create metadata directory");
+    let server_url = start_test_server(metadata.path()).await;
+    let (callback_url, mut rx) = start_callback_channel()
+        .await
+        .expect("start callback channel");
+    let group = "empty-diff-test";
+    let result = invoke(
+        &server_url,
+        &callback_url,
+        group,
+        "clone_repo",
+        serde_json::json!({ "repo": repo.path().to_str().expect("repository path") }),
+        &mut rx,
+        None,
+    )
+    .await;
+    assert!(result.contains("Repository initialized"), "{result}");
+
+    let (_, created_views) = invoke_collecting_views(
+        &server_url,
+        &callback_url,
+        group,
+        "create_file",
+        serde_json::json!({ "path": "added.txt", "content": "new content\n" }),
+        &mut rx,
+        1,
+    )
+    .await;
+    assert_eq!(created_views[0].content["files"][0]["path"], "added.txt");
+
+    let (_, deleted_views) = invoke_collecting_views(
+        &server_url,
+        &callback_url,
+        group,
+        "execute_command",
+        serde_json::json!({ "command": "rm added.txt" }),
+        &mut rx,
+        1,
+    )
+    .await;
+    assert_eq!(deleted_views[0].view_type, "diff");
+    assert_eq!(deleted_views[0].content["files"], serde_json::json!([]));
+}