From ca1a89c5c549a6e38ea807463f0096490086142f Mon Sep 17 00:00:00 2001
From: Jussi Maki <jussi@isovalent.com>
Date: Mon, 15 Apr 2024 10:48:03 +0200
Subject: [PATCH] Add finalizers to delete trackers

For safety, set a finalizer to make sure delete trackers are always
closed.

Signed-off-by: Jussi Maki <jussi@isovalent.com>
---
 deletetracker.go | 8 ++++++++
 txn.go           | 5 ++++-
 types.go         | 1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/deletetracker.go b/deletetracker.go
index a2e6a03..dc664ba 100644
--- a/deletetracker.go
+++ b/deletetracker.go
@@ -4,6 +4,7 @@
 package statedb
 
 import (
+	"runtime"
 	"sync/atomic"
 
 	"github.com/cilium/statedb/index"
@@ -53,8 +54,14 @@ func (dt *deleteTracker[Obj]) mark(upTo Revision) {
 }
 
 func (dt *deleteTracker[Obj]) close() {
+	if dt.db == nil {
+		return
+	}
+	runtime.SetFinalizer(dt, nil)
+
 	// Remove the delete tracker from the table.
 	txn := dt.db.WriteTxn(dt.table).getTxn()
+	dt.db = nil
 	db := txn.db
 	table := txn.modifiedTables[dt.table.tablePos()]
 	if table == nil {
@@ -71,6 +78,7 @@ func (dt *deleteTracker[Obj]) close() {
 	case db.gcTrigger <- struct{}{}:
 	default:
 	}
+
 }
 
 var closedWatchChannel = func() <-chan struct{} {
diff --git a/txn.go b/txn.go
index 3645a4c..310a84a 100644
--- a/txn.go
+++ b/txn.go
@@ -244,8 +244,11 @@ func (txn *txn) addDeleteTracker(meta TableMeta, trackerName string, dt anyDelet
 	table := txn.modifiedTables[meta.tablePos()]
 	_, _, table.deleteTrackers = table.deleteTrackers.Insert([]byte(trackerName), dt)
 	txn.db.metrics.DeleteTrackerCount(meta.Name(), table.deleteTrackers.Len())
-	return nil
 
+	// Add a finalizer to make sure delete trackers are always closed.
+	runtime.SetFinalizer(dt, func(dt anyDeleteTracker) { dt.close() })
+
+	return nil
 }
 
 func (txn *txn) delete(meta TableMeta, guardRevision Revision, data any) (object, bool, error) {
diff --git a/types.go b/types.go
index 4c6f811..84d6d15 100644
--- a/types.go
+++ b/types.go
@@ -352,6 +352,7 @@ type anyIndexer struct {
 type anyDeleteTracker interface {
 	setRevision(uint64)
 	getRevision() uint64
+	close()
 }
 
 type indexEntry struct {