From 2f17b3e2599a1ae8b0cc448c623fa0c25d6c50cb Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Fri, 11 Nov 2022 18:55:27 -0600
Subject: [PATCH] Fix create resource concurrently with Stat call race

https://github.com/jackc/pgx/issues/1148#issuecomment-1304898720
---
 pool.go      | 4 ++++
 pool_test.go | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/pool.go b/pool.go
index e18658c..f9190d6 100644
--- a/pool.go
+++ b/pool.go
@@ -427,8 +427,12 @@ func (p *Pool[T]) initResourceValue(ctx context.Context, res *Resource[T]) (*Res
 			return
 		}
 
+		// The resource is already in p.allResources where it might be read. So we need to acquire the lock to update its
+		// status.
+		p.mux.Lock()
 		res.value = value
 		res.status = resourceStatusAcquired
+		p.mux.Unlock()
 
 		// This select works because the channel is unbuffered.
 		select {
diff --git a/pool_test.go b/pool_test.go
index 45ee822..ac0d15b 100644
--- a/pool_test.go
+++ b/pool_test.go
@@ -985,6 +985,11 @@ func TestStress(t *testing.T) {
 				res.Release()
 			}
 		},
+		// Stat
+		func() {
+			stat := pool.Stat()
+			assert.NotNil(t, stat)
+		},
 	}
 
 	workerCount := int(poolSize) * 2