From 9b521d6097e9620f714e880318cb02bc7c214cfd Mon Sep 17 00:00:00 2001
From: Antonio Scandurra <me@as-cii.com>
Date: Wed, 22 Jun 2022 17:39:34 +0200
Subject: [PATCH] Use `Arc<Deterministic>` to understand which await points are
 parking

---
 crates/collab/src/integration_tests.rs | 23 +++++++++++++++++------
 crates/gpui/src/executor.rs            | 17 ++++++++++-------
 2 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/crates/collab/src/integration_tests.rs b/crates/collab/src/integration_tests.rs
index 3d8b128659a54a27c98c2eca2815ad34bec8288c..02c3a2ea8a6fe1d5e95aabcabab6b3b7ce27522f 100644
--- a/crates/collab/src/integration_tests.rs
+++ b/crates/collab/src/integration_tests.rs
@@ -4400,7 +4400,7 @@ async fn test_random_collaboration(
     deterministic: Arc<Deterministic>,
     rng: StdRng,
 ) {
-    cx.foreground().forbid_parking();
+    deterministic.forbid_parking();
     let max_peers = env::var("MAX_PEERS")
         .map(|i| i.parse().expect("invalid `MAX_PEERS` variable"))
         .unwrap_or(5);
@@ -4626,10 +4626,13 @@ async fn test_random_collaboration(
     while operations < max_operations {
         if operations == disconnect_host_at {
             server.disconnect_client(user_ids[0]);
-            cx.foreground().advance_clock(RECEIVE_TIMEOUT);
+            deterministic.advance_clock(RECEIVE_TIMEOUT);
             drop(op_start_signals);
+
+            deterministic.start_waiting();
             let mut clients = futures::future::join_all(clients).await;
-            cx.foreground().run_until_parked();
+            deterministic.finish_waiting();
+            deterministic.run_until_parked();
 
             let (host, host_project, mut host_cx, host_err) = clients.remove(0);
             if let Some(host_err) = host_err {
@@ -4681,6 +4684,8 @@ async fn test_random_collaboration(
                     cx.leak_detector(),
                     next_entity_id,
                 );
+
+                deterministic.start_waiting();
                 let guest = server.create_client(&mut guest_cx, &guest_username).await;
                 let guest_project = Project::remote(
                     host_project_id,
@@ -4693,6 +4698,8 @@ async fn test_random_collaboration(
                 )
                 .await
                 .unwrap();
+                deterministic.finish_waiting();
+
                 let op_start_signal = futures::channel::mpsc::unbounded();
                 user_ids.push(guest.current_user_id(&guest_cx));
                 op_start_signals.push(op_start_signal.0);
@@ -4715,8 +4722,10 @@ async fn test_random_collaboration(
                 op_start_signals.remove(guest_ix);
                 server.forbid_connections();
                 server.disconnect_client(removed_guest_id);
-                cx.foreground().advance_clock(RECEIVE_TIMEOUT);
+                deterministic.advance_clock(RECEIVE_TIMEOUT);
+                deterministic.start_waiting();
                 let (guest, guest_project, mut guest_cx, guest_err) = guest.await;
+                deterministic.finish_waiting();
                 server.allow_connections();
 
                 if let Some(guest_err) = guest_err {
@@ -4766,15 +4775,17 @@ async fn test_random_collaboration(
                 }
 
                 if rng.lock().gen_bool(0.8) {
-                    cx.foreground().run_until_parked();
+                    deterministic.run_until_parked();
                 }
             }
         }
     }
 
     drop(op_start_signals);
+    deterministic.start_waiting();
     let mut clients = futures::future::join_all(clients).await;
-    cx.foreground().run_until_parked();
+    deterministic.finish_waiting();
+    deterministic.run_until_parked();
 
     let (host_client, host_project, mut host_cx, host_err) = clients.remove(0);
     if let Some(host_err) = host_err {
diff --git a/crates/gpui/src/executor.rs b/crates/gpui/src/executor.rs
index 1bc8d61c44306abd612d412f4db9a5c18ba17136..76ee8ca4d6628bba8b72d31dd1ff78c191202088 100644
--- a/crates/gpui/src/executor.rs
+++ b/crates/gpui/src/executor.rs
@@ -366,6 +366,14 @@ impl Deterministic {
         self.state.lock().now = new_now;
     }
 
+    pub fn start_waiting(&self) {
+        self.state.lock().waiting_backtrace = Some(backtrace::Backtrace::new_unresolved());
+    }
+
+    pub fn finish_waiting(&self) {
+        self.state.lock().waiting_backtrace.take();
+    }
+
     pub fn forbid_parking(&self) {
         use rand::prelude::*;
 
@@ -500,10 +508,7 @@ impl Foreground {
     #[cfg(any(test, feature = "test-support"))]
     pub fn start_waiting(&self) {
         match self {
-            Self::Deterministic { executor, .. } => {
-                executor.state.lock().waiting_backtrace =
-                    Some(backtrace::Backtrace::new_unresolved());
-            }
+            Self::Deterministic { executor, .. } => executor.start_waiting(),
             _ => panic!("this method can only be called on a deterministic executor"),
         }
     }
@@ -511,9 +516,7 @@ impl Foreground {
     #[cfg(any(test, feature = "test-support"))]
     pub fn finish_waiting(&self) {
         match self {
-            Self::Deterministic { executor, .. } => {
-                executor.state.lock().waiting_backtrace.take();
-            }
+            Self::Deterministic { executor, .. } => executor.finish_waiting(),
             _ => panic!("this method can only be called on a deterministic executor"),
         }
     }