Fix #2488 LockRecursionException when doing FindById

LiteDB.Tests/Issues/Issue2471_Test.cs

@@ -0,0 +1,36 @@
+using FluentAssertions;
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Xunit;
+
+namespace LiteDB.Tests.Issues;
+
+public class Issue2471_Test
+{
+    [Fact]
+    public void TestFragmentDB_FindByIDException()
+    {
+        using var db = new LiteDatabase(":memory:");
+        var collection = db.GetCollection<object>("fragtest");
+
+        var fragment = new object { };
+        var id = collection.Insert(fragment);
+
+        id.Should().BeGreaterThan(0);
+
+        var frag2 = collection.FindById(id);
+        frag2.Should().NotBeNull();
+
+        Action act = () => db.Checkpoint();
+
+        //act.Should().Throw<LockRecursionException>();
+        act.Should().NotThrow();
+    }
+}

LiteDB/Engine/Query/QueryExecutor.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using static LiteDB.Constants;
@@ -130,28 +130,9 @@ IEnumerable<BsonDocument> RunQuery()
 
                 using (var enumerator = pipe.Pipe(nodes, queryPlan).GetEnumerator())
                 {
-                    var read = false;
-
                     try
                     {
-                        read = enumerator.MoveNext();
-                    }
-                    catch (Exception ex)
-                    {
-                        _state.Handle(ex);
-                        throw ex;
-                    }
-
-                    while (read)
-                    {
-                        _cursor.Fetched++;
-                        _cursor.Elapsed.Stop();
-
-                        yield return enumerator.Current;
-
-                        if (transaction.State != TransactionState.Active) throw new LiteException(0, $"There is no more active transaction for this cursor: {_cursor.Query.ToSQL(_cursor.Collection)}");
-
-                        _cursor.Elapsed.Start();
+                        var read = false;
 
                         try
                         {
@@ -162,6 +143,36 @@ IEnumerable<BsonDocument> RunQuery()
                             _state.Handle(ex);
                             throw ex;
                         }
+
+                        while (read)
+                        {
+                            _cursor.Fetched++;
+                            _cursor.Elapsed.Stop();
+
+                            yield return enumerator.Current;
+
+                            if (transaction.State != TransactionState.Active) throw new LiteException(0, $"There is no more active transaction for this cursor: {_cursor.Query.ToSQL(_cursor.Collection)}");
+
+                            _cursor.Elapsed.Start();
+
+                            try
+                            {
+                                read = enumerator.MoveNext();
+                            }
+                            catch (Exception ex)
+                            {
+                                _state.Handle(ex);
+                                throw ex;
+                            }
+                        }
+                    }
+                    finally
+                    {
+                        if (isNew)
+                        {
+                            _monitor.ReleaseTransaction(transaction);
+                            isNew = false;
+                        }
                     }
                 }