1 files changed, 35 insertions, 0 deletions
diff --git a/third_party/rust/tracing/tests/scoped_clobbers_default.rs b/third_party/rust/tracing/tests/scoped_clobbers_default.rs
new file mode 100644
index 0000000000..362d34a82c
--- /dev/null
+++ b/third_party/rust/tracing/tests/scoped_clobbers_default.rs
@@ -0,0 +1,35 @@
+#![cfg(feature = "std")]
+use tracing_mock::*;
+
+#[test]
+fn scoped_clobbers_global() {
+    // Reproduces https://github.com/tokio-rs/tracing/issues/2050
+
+    let (scoped, scoped_handle) = subscriber::mock()
+        .event(event::msg("before global"))
+        .event(event::msg("before drop"))
+        .done()
+        .run_with_handle();
+
+    let (global, global_handle) = subscriber::mock()
+        .event(event::msg("after drop"))
+        .done()
+        .run_with_handle();
+
+    // Set a scoped default subscriber, returning a guard.
+    let guard = tracing::subscriber::set_default(scoped);
+    tracing::info!("before global");
+
+    // Now, set the global default.
+    tracing::subscriber::set_global_default(global)
+        .expect("global default should not already be set");
+    // This event should still be collected by the scoped default.
+    tracing::info!("before drop");
+
+    // Drop the guard. Now, the global default subscriber should be used.
+    drop(guard);
+    tracing::info!("after drop");
+
+    scoped_handle.assert_finished();
+    global_handle.assert_finished();
+}