fixes #71295 (#71924)

src/libraries/Microsoft.Extensions.Configuration.Json/src/JsonConfigurationFileParser.cs

@@ -34,13 +34,13 @@ internal sealed class JsonConfigurationFileParser
                 {
                     throw new FormatException(SR.Format(SR.Error_InvalidTopLevelJSONElement, doc.RootElement.ValueKind));
                 }
-                VisitElement(doc.RootElement);
+                VisitObjectElement(doc.RootElement);
             }
 
             return _data;
         }
 
-        private void VisitElement(JsonElement element)
+        private void VisitObjectElement(JsonElement element)
         {
             var isEmpty = true;
 
@@ -52,6 +52,26 @@ private void VisitElement(JsonElement element)
                 ExitContext();
             }
 
+            SetNullIfElementIsEmpty(isEmpty);
+        }
+
+        private void VisitArrayElement(JsonElement element)
+        {
+            int index = 0;
+
+            foreach (JsonElement arrayElement in element.EnumerateArray())
+            {
+                EnterContext(index.ToString());
+                VisitValue(arrayElement);
+                ExitContext();
+                index++;
+            }
+
+            SetNullIfElementIsEmpty(isEmpty: index == 0);
+        }
+
+        private void SetNullIfElementIsEmpty(bool isEmpty)
+        {
             if (isEmpty && _paths.Count > 0)
             {
                 _data[_paths.Peek()] = null;
@@ -65,18 +85,11 @@ private void VisitValue(JsonElement value)
             switch (value.ValueKind)
             {
                 case JsonValueKind.Object:
-                    VisitElement(value);
+                    VisitObjectElement(value);
                     break;
 
                 case JsonValueKind.Array:
-                    int index = 0;
-                    foreach (JsonElement arrayElement in value.EnumerateArray())
-                    {
-                        EnterContext(index.ToString());
-                        VisitValue(arrayElement);
-                        ExitContext();
-                        index++;
-                    }
+                    VisitArrayElement(value);
                     break;
 
                 case JsonValueKind.Number:

src/libraries/Microsoft.Extensions.Configuration.Json/tests/ArrayTest.cs

@@ -254,5 +254,37 @@ public void TrailingCommas()
             Assert.Equal("9.10.11.12", jsonConfigSource.Get("ip:1:0"));
             Assert.Equal("13.14.15.16", jsonConfigSource.Get("ip:1:1"));
         }
+
+        [Fact]
+        public void EmptyArrayNotIgnored()
+        {
+            var json = @"{
+                ""ip"": {
+                    ""array"": [
+                    ],
+                    ""object"":{
+                    }
+                }
+            }";
+
+            var jsonConfigSource = new JsonConfigurationSource { FileProvider = TestStreamHelpers.StringToFileProvider(json) };
+
+            var configurationBuilder = new ConfigurationBuilder();
+            configurationBuilder.Add(jsonConfigSource);
+            var config = configurationBuilder.Build();
+
+            var configurationSection = config.GetSection("ip");
+
+            var ipSectionChildren = configurationSection.GetChildren().ToArray();
+
+            Assert.Equal(1, config.GetChildren().Count());
+            Assert.Equal(2, ipSectionChildren.Count());
+            Assert.Equal("array", ipSectionChildren[0].Key);
+            Assert.Null(ipSectionChildren[0].Value);
+            Assert.Equal("object", ipSectionChildren[1].Key);
+            Assert.Null(ipSectionChildren[1].Value);
+            Assert.Equal(0, ipSectionChildren[0].GetChildren().Count());
+            Assert.Equal(0, ipSectionChildren[1].GetChildren().Count());
+        }
     }
 }