fix(in-memory): resolve orphaned skiplist arena leak on Close

db.go

@@ -625,6 +625,9 @@ func (db *DB) close() (err error) {
 	db.threshold.close()
 
 	if db.opt.InMemory {
+		for _, mem := range db.imm{
+			mem.DecrRef()
+		}
 		return
 	}
 

issue_2205_test.go

@@ -0,0 +1,34 @@
+package badger
+
+import (
+	"testing"
+)
+
+func TestIssue2205_MemoryLeak(t *testing.T) {
+	// Loop 1000 times to force the leak to accumulate
+	for i := 0; i < 1000; i++ {
+		// Initialize an in-memory database configuration
+		opt := DefaultOptions("").WithInMemory(true)
+		opt.Logger = nil // Turn off logging so our terminal doesn't get spammed
+
+		db, err := Open(opt)
+		if err != nil {
+			t.Fatalf("Failed to open DB on iteration %d: %v", i, err)
+		}
+
+		// Perform a single write transaction
+		err = db.Update(func(txn *Txn) error {
+			return txn.Set([]byte("leak-test"), []byte("value"))
+		})
+		if err != nil {
+			t.Fatalf("Failed to write on iteration %d: %v", i, err)
+		}
+
+		// Close the database. This is where the bug lives!
+		// It is supposed to clean up everything, but it's leaving something behind.
+		err = db.Close()
+		if err != nil {
+			t.Fatalf("Failed to close DB on iteration %d: %v", i, err)
+		}
+	}
+}