WIP: failing randomized test

SEED=175 MAX_PEERS=2 ITERATIONS=1 OPERATIONS=159 cargo test --package=collab random -- --nocapture

Cargo.lock

@@ -4437,6 +4437,7 @@ dependencies = [
  "aho-corasick",
  "anyhow",
  "async-trait",
+ "backtrace",
  "client",
  "clock",
  "collections",

crates/project/Cargo.toml

@@ -37,6 +37,7 @@ util = { path = "../util" }
 aho-corasick = "0.7"
 anyhow = "1.0.57"
 async-trait = "0.1"
+backtrace = "0.3"
 futures = "0.3"
 ignore = "0.4"
 lazy_static = "1.4.0"

crates/project/src/project.rs

@@ -4635,7 +4635,12 @@ impl Project {
             let is_host = collaborator.replica_id == 0;
             this.collaborators.insert(new_peer_id, collaborator);
 
-            if let Some(buffers) = this.shared_buffers.remove(&old_peer_id) {
+            let buffers = this.shared_buffers.remove(&old_peer_id);
+            println!(
+                "peer {} became {}. moving buffers {:?}",
+                old_peer_id, new_peer_id, &buffers
+            );
+            if let Some(buffers) = buffers {
                 this.shared_buffers.insert(new_peer_id, buffers);
             }
 
@@ -5610,6 +5615,13 @@ impl Project {
     ) -> u64 {
         let buffer_id = buffer.read(cx).remote_id();
         if let Some(project_id) = self.remote_id() {
+            if buffer_id == 300015 {
+                println!(
+                    "creating buffer for peer {}. {:?}",
+                    peer_id,
+                    backtrace::Backtrace::new()
+                );
+            }
             let shared_buffers = self.shared_buffers.entry(peer_id).or_default();
             if shared_buffers.insert(buffer_id) {
                 let buffer = buffer.read(cx);