2 files changed, 36 insertions, 6 deletions

diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index a77d63dc5e..0764c7d17a 100644
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -2944,15 +2944,17 @@ func (rs *Rows) initContextClose(ctx, txctx context.Context) {
 	if bypassRowsAwaitDone {
 		return
 	}
-	ctx, rs.cancel = context.WithCancel(ctx)
-	go rs.awaitDone(ctx, txctx)
+	closectx, cancel := context.WithCancel(ctx)
+	rs.cancel = cancel
+	go rs.awaitDone(ctx, txctx, closectx)
 }
 
-// awaitDone blocks until either ctx or txctx is canceled. The ctx is provided
-// from the query context and is canceled when the query Rows is closed.
+// awaitDone blocks until ctx, txctx, or closectx is canceled. 
+// The ctx is provided from the query context.
 // If the query was issued in a transaction, the transaction's context
-// is also provided in txctx to ensure Rows is closed if the Tx is closed.
-func (rs *Rows) awaitDone(ctx, txctx context.Context) {
+// is also provided in txctx, to ensure Rows is closed if the Tx is closed.
+// The closectx is closed by an explicit call to rs.Close.
+func (rs *Rows) awaitDone(ctx, txctx, closectx context.Context) {
 	var txctxDone <-chan struct{}
 	if txctx != nil {
 		txctxDone = txctx.Done()
@@ -2964,6 +2966,9 @@ func (rs *Rows) awaitDone(ctx, txctx context.Context) {
 	case <-txctxDone:
 		err := txctx.Err()
 		rs.contextDone.Store(&err)
+	case <-closectx.Done():
+		// rs.cancel was called via Close(); don't store this into contextDone
+		// to ensure Err() is unaffected.
 	}
 	rs.close(ctx.Err())
 }
diff --git a/src/database/sql/sql_test.go b/src/database/sql/sql_test.go
index 718056c351..e6a5cd912a 100644
--- a/src/database/sql/sql_test.go
+++ b/src/database/sql/sql_test.go
@@ -4493,6 +4493,31 @@ func TestContextCancelBetweenNextAndErr(t *testing.T) {
 	}
 }
 
+func TestNilErrorAfterClose(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	// This WithCancel is important; Rows contains an optimization to avoid
+	// spawning a goroutine when the query/transaction context cannot be
+	// canceled, but this test tests a bug which is caused by said goroutine.
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	r, err := db.QueryContext(ctx, "SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := r.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	time.Sleep(10 * time.Millisecond) // increase odds of seeing failure
+	if err := r.Err(); err != nil {
+		t.Fatal(err)
+	}
+}
+
 // badConn implements a bad driver.Conn, for TestBadDriver.
 // The Exec method panics.
 type badConn struct{}