[release/6.0] Revert bind single elements to array in configuration binder (#59733)

* Revert "Apply feedback from PR #57204 (#57872)"

This reverts commit e4a455f.

* Revert "Allow ConfigBinder to bind arrays to Singular elements (#57204)"

This reverts commit 7f595ce.

Co-authored-by: Santiago Fernandez Madero <[email protected]>

Author: github-actions[bot]

src/libraries/Microsoft.Extensions.Configuration.Binder/src/ConfigurationBinder.cs

@@ -19,10 +19,6 @@ public static class ConfigurationBinder
         private const string TrimmingWarningMessage = "In case the type is non-primitive, the trimmer cannot statically analyze the object's type so its members may be trimmed.";
         private const string InstanceGetTypeTrimmingWarningMessage = "Cannot statically analyze the type of instance so its members may be trimmed";
         private const string PropertyTrimmingWarningMessage = "Cannot statically analyze property.PropertyType so its members may be trimmed.";
-        private const string BindSingleElementsToArraySwitch = "Microsoft.Extensions.Configuration.BindSingleElementsToArray";
-
-        // Enable this switch by default.
-        private static bool ShouldBindSingleElementsToArray { get; } = AppContext.TryGetSwitch(BindSingleElementsToArraySwitch, out bool verifyCanBindSingleElementsToArray) ? verifyCanBindSingleElementsToArray : true;
 
         /// <summary>
         /// Attempts to bind the configuration instance to a new instance of type T.
@@ -366,7 +362,7 @@ private static object BindInstance(
                 return convertedValue;
             }
 
-            if (config != null && (config.GetChildren().Any() || (configValue != null && ShouldBindSingleElementsToArray)))
+            if (config != null && config.GetChildren().Any())
             {
                 // If we don't have an instance, try to create one
                 if (instance == null)
@@ -499,7 +495,7 @@ private static void BindCollection(
             Type itemType = collectionType.GenericTypeArguments[0];
             MethodInfo addMethod = collectionType.GetMethod("Add", DeclaredOnlyLookup);
 
-            foreach (IConfigurationSection section in GetChildrenOrSelf(config))
+            foreach (IConfigurationSection section in config.GetChildren())
             {
                 try
                 {
@@ -522,7 +518,7 @@ private static void BindCollection(
         [RequiresUnreferencedCode("Cannot statically analyze what the element type is of the Array so its members may be trimmed.")]
         private static Array BindArray(Array source, IConfiguration config, BinderOptions options)
         {
-            IConfigurationSection[] children = GetChildrenOrSelf(config).ToArray();
+            IConfigurationSection[] children = config.GetChildren().ToArray();
             int arrayLength = source.Length;
             Type elementType = source.GetType().GetElementType();
             var newArray = Array.CreateInstance(elementType, arrayLength + children.Length);
@@ -706,26 +702,5 @@ private static string GetPropertyName(MemberInfo property)
 
             return property.Name;
         }
-
-        private static IEnumerable<IConfigurationSection> GetChildrenOrSelf(IConfiguration config)
-        {
-            if (!ShouldBindSingleElementsToArray)
-            {
-                return config.GetChildren();
-            }
-
-            IEnumerable<IConfigurationSection> children;
-            // If configuration's children is an array, the configuration key will be a number
-            if (config.GetChildren().Any(a => long.TryParse(a.Key, out _)))
-            {
-                children = config.GetChildren();
-            }
-            else
-            {
-                children = new[] { config as IConfigurationSection };
-            }
-
-            return children;
-        }
     }
-}
+}

src/libraries/Microsoft.Extensions.Configuration.Binder/tests/ConfigurationBinderTests.cs

@@ -5,7 +5,6 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Reflection;
-using Microsoft.DotNet.RemoteExecutor;
 using Xunit;
 
 namespace Microsoft.Extensions.Configuration.Binder.Test
@@ -937,59 +936,6 @@ public void ExceptionWhenTryingToBindToByteArray()
                 exception.Message);
         }
 
-        [Fact]
-        public void CanBindSingleElementToCollection()
-        {
-            var dic = new Dictionary<string, string>
-            {
-                {"MyString", "hello world"},
-                {"Nested:Integer", "11"},
-            };
-
-            var configurationBuilder = new ConfigurationBuilder();
-            configurationBuilder.AddInMemoryCollection(dic);
-            IConfiguration config = configurationBuilder.Build();
-
-            var stringArr = config.GetSection("MyString").Get<string[]>();
-            Assert.Equal("hello world", stringArr[0]);
-            Assert.Equal(1, stringArr.Length);
-
-            var stringAsStr = config.GetSection("MyString").Get<string>();
-            Assert.Equal("hello world", stringAsStr);
-
-            var nested = config.GetSection("Nested").Get<NestedOptions>();
-            Assert.Equal(11, nested.Integer);
-
-            var nestedAsArray = config.GetSection("Nested").Get<NestedOptions[]>();
-            Assert.Equal(11, nestedAsArray[0].Integer);
-            Assert.Equal(1, nestedAsArray.Length);
-        }
-
-        [ConditionalFact(typeof(RemoteExecutor), nameof(RemoteExecutor.IsSupported))]
-        public void CannotBindSingleElementToCollectionWhenSwitchSet()
-        {
-            RemoteExecutor.Invoke(() =>
-            {
-                AppContext.SetSwitch("Microsoft.Extensions.Configuration.BindSingleElementsToArray", false);
-
-                var dic = new Dictionary<string, string>
-                {
-                    {"MyString", "hello world"},
-                    {"Nested:Integer", "11"},
-                };
-
-                var configurationBuilder = new ConfigurationBuilder();
-                configurationBuilder.AddInMemoryCollection(dic);
-                IConfiguration config = configurationBuilder.Build();
-
-                var stringArr = config.GetSection("MyString").Get<string[]>();
-                Assert.Null(stringArr);
-
-                var stringAsStr = config.GetSection("MyString").Get<string>();
-                Assert.Equal("hello world", stringAsStr);
-            }).Dispose();
-        }
-
         private interface ISomeInterface
         {
         }

src/libraries/Microsoft.Extensions.Configuration.Binder/tests/Microsoft.Extensions.Configuration.Binder.Tests.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);net461</TargetFrameworks>
     <EnableDefaultItems>true</EnableDefaultItems>
-    <IncludeRemoteExecutor>true</IncludeRemoteExecutor>
   </PropertyGroup>
 
   <ItemGroup>