Avoid a JsonException that gets thrown when there are ignored properties under some circumstances.

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/StjFeatureCollectionConverter.cs

@@ -65,7 +65,7 @@ public override FeatureCollection Read(ref Utf8JsonReader reader, Type objectTyp
                 else
                 {
                     reader.ReadOrThrow();
-                    reader.Skip();
+                    reader.SkipOrThrow();
                     reader.ReadOrThrow();
                 }
             }

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/StjFeatureConverter.cs

@@ -162,7 +162,7 @@ public override IFeature Read(ref Utf8JsonReader reader, Type objectType, JsonSe
 
                     default:
                         // If property name is not one of the above: skip it entirely (foreign member)
-                        reader.Skip();
+                        reader.SkipOrThrow();
                         // Advance
                         while (reader.Read())
                         {

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/StjGeometryConverter.cs

@@ -96,7 +96,7 @@ public override Geometry Read(ref Utf8JsonReader reader, Type typeToConvert, Jso
                         break;
                     default: // included "bbox" property
                         //read, but can't do anything with it (see NetTopologySuite.IO.GeoJSON => NetTopologySuite.IO.Converters.GeometryConverter.ParseGeometry)
-                        reader.Skip();
+                        reader.SkipOrThrow();
                         reader.Read();
                         break;
                 }

src/NetTopologySuite.IO.GeoJSON4STJ/Converters/Utility.cs

@@ -61,6 +61,21 @@ internal static void AssertToken(this ref Utf8JsonReader reader, JsonTokenType r
             }
         }
 
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        internal static void SkipOrThrow(this ref Utf8JsonReader reader)
+        {
+            // #143: Even though JsonConverter<T> always seems to see a Utf8JsonReader positioned on
+            // a full node, that node might be contained in a larger incomplete block. For whatever
+            // reason, reader.Skip() throws JsonException immediately if the reader is in a partial
+            // block, even if the current block has plenty of data to read past it. TrySkip will do
+            // the right thing, but we should still check the return value to make sure that we get
+            // a JsonException if the reader *does* terminate abruptly (airbreather 2024-04-24).
+            if (!reader.TrySkip())
+            {
+                ThrowForUnexpectedPartialJson();
+            }
+        }
+
         internal static object ObjectFromJsonNode(JsonNode node, JsonSerializerOptions serializerOptions)
         {
             switch (node)
@@ -93,6 +108,10 @@ internal static JsonNode ObjectToJsonNode(object obj, JsonSerializerOptions seri
         private static void ThrowForUnexpectedEndOfStream()
             => throw new JsonException(Resources.EX_UnexpectedEndOfStream);
 
+        [MethodImpl(MethodImplOptions.NoInlining)]
+        private static void ThrowForUnexpectedPartialJson()
+            => throw new JsonException(Resources.EX_UnexpectedPartialJson);
+
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static void ThrowForUnexpectedToken(JsonTokenType requiredNextTokenType, ref Utf8JsonReader reader)
             => throw new JsonException(string.Format(Resources.EX_UnexpectedToken, requiredNextTokenType, reader.TokenType, CurrentTokenAsString(in reader)));

src/NetTopologySuite.IO.GeoJSON4STJ/Properties/Resources.resx

@@ -141,4 +141,7 @@
   <data name="EX_UnexpectedToken" xml:space="preserve">
     <value>Expected token is '{0}' but was '{1}' (Value '{2}').</value>
   </data>
+  <data name="EX_UnexpectedPartialJson" xml:space="preserve">
+    <value>JsonConverter received partial JSON. This is likely the result of a bug in the System.Text.Json library.</value>
+  </data>
 </root>

test/NetTopologySuite.IO.GeoJSON4STJ.Test/Converters/FeatureCollectionConverterTest.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Linq;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 using NetTopologySuite.Features;
 using NetTopologySuite.Geometries;
@@ -68,5 +70,20 @@ public void TestSanD(OgcGeometryType type, int num, bool threeD)
             for (int i = 0; i < fc.Count; i++)
                 FeatureConverterTest.CheckEquality(fc[i], d[i]);
         }
+
+        [Test]
+        [GeoJsonIssueNumber(143)]
+        public void SkippedPropertiesShouldNotThrowWithCompleteObjectInPartialBuffer()
+        {
+            var options = DefaultOptions;
+            var node = JsonSerializer.SerializeToNode(new FeatureCollection(), options)!;
+            node["_skippedProperty"] = "irrelevant";
+            var nodes = Enumerable.Repeat(node, 500).ToArray();
+            using SingleByteReadingMemoryStream stream = new();
+            JsonSerializer.Serialize(stream, nodes, options);
+            stream.Position = 0;
+            var roundtrip = JsonSerializer.Deserialize<FeatureCollection[]>(stream, options);
+            Assert.That(roundtrip, Has.Length.EqualTo(500));
+        }
     }
 }

test/NetTopologySuite.IO.GeoJSON4STJ.Test/Converters/FeatureConverterTest.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
@@ -128,6 +129,21 @@ public void WriteJsonWithIdTest(string idPropertyName, object id)
             CheckEquality(value, deserialized, idPropertyName);
         }
 
+        [Test]
+        [GeoJsonIssueNumber(143)]
+        public void SkippedPropertiesShouldNotThrowWithCompleteObjectInPartialBuffer()
+        {
+            var options = DefaultOptions;
+            var node = JsonSerializer.SerializeToNode(new Feature(), options)!;
+            node["_skippedProperty"] = "irrelevant";
+            var nodes = Enumerable.Repeat(node, 500).ToArray();
+            using SingleByteReadingMemoryStream stream = new();
+            JsonSerializer.Serialize(stream, nodes, options);
+            stream.Position = 0;
+            var roundtrip = JsonSerializer.Deserialize<IFeature[]>(stream, options);
+            Assert.That(roundtrip, Has.Length.EqualTo(500));
+        }
+
         public static IEnumerable<object[]> FeatureIdTestCases
         {
             get

test/NetTopologySuite.IO.GeoJSON4STJ.Test/Converters/GeometryConverterTest.cs

@@ -1,4 +1,5 @@
 using System.IO;
+using System.Linq;
 using System.Text.Json;
 using NetTopologySuite.Geometries;
 using NUnit.Framework;
@@ -184,5 +185,20 @@ public void TestWriteReadWkt(string wkt)
 
             Assert.That(geomS.IsEmpty ? geomD.IsEmpty : geomS.EqualsTopologically(geomD));
         }
+
+        [Test]
+        [GeoJsonIssueNumber(143)]
+        public void SkippedPropertiesShouldNotThrowWithCompleteObjectInPartialBuffer()
+        {
+            var options = DefaultOptions;
+            var node = JsonSerializer.SerializeToNode(Point.Empty, options)!;
+            node["_skippedProperty"] = "irrelevant";
+            var nodes = Enumerable.Repeat(node, 500).ToArray();
+            using SingleByteReadingMemoryStream stream = new();
+            JsonSerializer.Serialize(stream, nodes, options);
+            stream.Position = 0;
+            var roundtrip = JsonSerializer.Deserialize<Geometry[]>(stream, options);
+            Assert.That(roundtrip, Has.Length.EqualTo(500));
+        }
     }
 }

test/NetTopologySuite.IO.GeoJSON4STJ.Test/SingleByteReadingMemoryStream.cs

@@ -0,0 +1,32 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace NetTopologySuite.IO.GeoJSON4STJ.Test;
+
+/// <summary>
+/// A <see cref="MemoryStream"/> implementation that will never read more than one byte at a time.
+/// </summary>
+internal sealed class SingleByteReadingMemoryStream : MemoryStream
+{
+    public override int Read(byte[] buffer, int offset, int count)
+    {
+        return base.Read(buffer, offset, Math.Min(1, count));
+    }
+
+    public override int Read(Span<byte> buffer)
+    {
+        return base.Read(buffer[.. Math.Min(1, buffer.Length)]);
+    }
+
+    public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+    {
+        return base.ReadAsync(buffer, offset, Math.Min(1, count), cancellationToken);
+    }
+
+    public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+    {
+        return base.ReadAsync(buffer[.. Math.Min(1, buffer.Length)], cancellationToken);
+    }
+}