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Add System.Linq Chunk extension method (#47965)
* Add System.Linq Chunk extension method Fix #27449 * Use explicit types instead of type inference * Seperate inner and outer loop * Rename parameter maxSize to size * Add missing license header * Remove Chunk.SpeedOpt.cs * Add tests to verify Chunk works after mutations * Add/remove before getting enumerator in tests * Test content of chunk method for IQueryable<T>
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‎src/libraries/System.Linq.Queryable/ref/System.Linq.Queryable.cs

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@@ -65,6 +65,7 @@ public static partial class Queryable
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public static float? Average<TSource>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<System.Func<TSource, float?>> selector) { throw null; }
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public static float Average<TSource>(this System.Linq.IQueryable<TSource> source, System.Linq.Expressions.Expression<System.Func<TSource, float>> selector) { throw null; }
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public static System.Linq.IQueryable<TResult> Cast<TResult>(this System.Linq.IQueryable source) { throw null; }
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public static System.Linq.IQueryable<TSource[]> Chunk<TSource>(this System.Linq.IQueryable<TSource> source, int size) { throw null; }
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public static System.Linq.IQueryable<TSource> Concat<TSource>(this System.Linq.IQueryable<TSource> source1, System.Collections.Generic.IEnumerable<TSource> source2) { throw null; }
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public static bool Contains<TSource>(this System.Linq.IQueryable<TSource> source, TSource item) { throw null; }
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public static bool Contains<TSource>(this System.Linq.IQueryable<TSource> source, TSource item, System.Collections.Generic.IEqualityComparer<TSource>? comparer) { throw null; }

‎src/libraries/System.Linq.Queryable/src/ILLink/ILLink.Suppressions.xml

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@@ -109,6 +109,12 @@
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<property name="Scope">member</property>
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<property name="Target">M:System.Linq.CachedReflectionInfo.Cast_TResult_1(System.Type)</property>
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</attribute>
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<attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
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<argument>ILLink</argument>
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<argument>IL2060</argument>
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<property name="Scope">member</property>
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<property name="Target">M:System.Linq.CachedReflectionInfo.Chunk_TSource_1(System.Type)</property>
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</attribute>
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<attribute fullname="System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute">
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<argument>ILLink</argument>
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<argument>IL2060</argument>

‎src/libraries/System.Linq.Queryable/src/System/Linq/CachedReflection.cs

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@@ -188,6 +188,13 @@ public static MethodInfo Cast_TResult_1(Type TResult) =>
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(s_Cast_TResult_1 = new Func<IQueryable, IQueryable<object>>(Queryable.Cast<object>).GetMethodInfo().GetGenericMethodDefinition()))
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.MakeGenericMethod(TResult);
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private static MethodInfo? s_Chunk_TSource_1;
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public static MethodInfo Chunk_TSource_1(Type TSource) =>
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(s_Chunk_TSource_1 ??
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(s_Chunk_TSource_1 = new Func<IQueryable<object>, int, IQueryable<object>>(Queryable.Chunk).GetMethodInfo().GetGenericMethodDefinition()))
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.MakeGenericMethod(TSource);
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private static MethodInfo? s_Concat_TSource_2;
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public static MethodInfo Concat_TSource_2(Type TSource) =>

‎src/libraries/System.Linq.Queryable/src/System/Linq/Queryable.cs

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@@ -614,6 +614,19 @@ public static IQueryable<TSource> Distinct<TSource>(this IQueryable<TSource> sou
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));
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}
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[DynamicDependency("Chunk`1", typeof(Enumerable))]
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public static IQueryable<TSource[]> Chunk<TSource>(this IQueryable<TSource> source, int size)
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{
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if (source == null)
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throw Error.ArgumentNull(nameof(source));
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return source.Provider.CreateQuery<TSource[]>(
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Expression.Call(
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null,
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CachedReflectionInfo.Chunk_TSource_1(typeof(TSource)),
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source.Expression, Expression.Constant(size)
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));
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}
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[DynamicDependency("Concat`1", typeof(Enumerable))]
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public static IQueryable<TSource> Concat<TSource>(this IQueryable<TSource> source1, IEnumerable<TSource> source2)
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{

‎src/libraries/System.Linq.Queryable/tests/ChunkTests.cs

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@@ -0,0 +1,26 @@
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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using Xunit;
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namespace System.Linq.Tests
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{
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public class ChunkTests : EnumerableBasedTests
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{
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[Fact]
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public void ThrowsOnNullSource()
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{
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IQueryable<int> source = null;
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AssertExtensions.Throws<ArgumentNullException>("source", () => source.Chunk(5));
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}
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[Fact]
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public void Chunk()
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{
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var chunked = new[] {0, 1, 2}.AsQueryable().Chunk(2);
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Assert.Equal(2, chunked.Count());
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Assert.Equal(new[] {new[] {0, 1}, new[] {2}}, chunked);
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}
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}
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}

‎src/libraries/System.Linq.Queryable/tests/System.Linq.Queryable.Tests.csproj

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@@ -9,6 +9,7 @@
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<Compile Include="AppendPrependTests.cs" />
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<Compile Include="AverageTests.cs" />
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<Compile Include="CastTests.cs" />
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<Compile Include="ChunkTests.cs" />
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<Compile Include="ConcatTests.cs" />
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<Compile Include="ContainsTests.cs" />
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<Compile Include="CountTests.cs" />

‎src/libraries/System.Linq/ref/System.Linq.cs

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@@ -41,6 +41,7 @@ public static System.Collections.Generic.IEnumerable<
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TResult
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#nullable restore
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> Cast<TResult>(this System.Collections.IEnumerable source) { throw null; }
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public static System.Collections.Generic.IEnumerable<TSource[]> Chunk<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, int size) { throw null; }
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public static System.Collections.Generic.IEnumerable<TSource> Concat<TSource>(this System.Collections.Generic.IEnumerable<TSource> first, System.Collections.Generic.IEnumerable<TSource> second) { throw null; }
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public static bool Contains<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource value) { throw null; }
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public static bool Contains<TSource>(this System.Collections.Generic.IEnumerable<TSource> source, TSource value, System.Collections.Generic.IEqualityComparer<TSource>? comparer) { throw null; }

‎src/libraries/System.Linq/src/System.Linq.csproj

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@@ -50,6 +50,7 @@
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<Compile Include="System\Linq\Average.cs" />
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<Compile Include="System\Linq\Buffer.cs" />
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<Compile Include="System\Linq\Cast.cs" />
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<Compile Include="System\Linq\Chunk.cs" />
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<Compile Include="System\Linq\Concat.cs" />
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<Compile Include="System\Linq\Contains.cs" />
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<Compile Include="System\Linq\Count.cs" />

‎src/libraries/System.Linq/src/System/Linq/Chunk.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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namespace System.Linq
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{
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public static partial class Enumerable
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{
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/// <summary>
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/// Split the elements of a sequence into chunks of size at most <paramref name="size"/>.
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/// </summary>
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/// <remarks>
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/// Every chunk except the last will be of size <paramref name="size"/>.
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/// The last chunk will contain the remaining elements and may be of a smaller size.
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/// </remarks>
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/// <param name="source">
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/// An <see cref="IEnumerable{T}"/> whose elements to chunk.
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/// </param>
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/// <param name="size">
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/// Maximum size of each chunk.
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/// </param>
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/// <typeparam name="TSource">
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/// The type of the elements of source.
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/// </typeparam>
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/// <returns>
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/// An <see cref="IEnumerable{T}"/> that contains the elements the input sequence split into chunks of size <paramref name="size"/>.
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/// </returns>
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/// <exception cref="ArgumentNullException">
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/// <paramref name="source"/> is null.
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/// </exception>
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/// <exception cref="ArgumentOutOfRangeException">
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/// <paramref name="size"/> is below 1.
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/// </exception>
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public static IEnumerable<TSource[]> Chunk<TSource>(this IEnumerable<TSource> source, int size)
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{
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if (source == null)
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{
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ThrowHelper.ThrowArgumentNullException(ExceptionArgument.source);
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}
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if (size < 1)
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{
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ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.size);
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}
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return ChunkIterator(source, size);
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}
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private static IEnumerable<TSource[]> ChunkIterator<TSource>(IEnumerable<TSource> source, int size)
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{
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using IEnumerator<TSource> e = source.GetEnumerator();
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while (e.MoveNext())
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{
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TSource[] chunk = new TSource[size];
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chunk[0] = e.Current;
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for (int i = 1; i < size; i++)
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{
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if (!e.MoveNext())
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{
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Array.Resize(ref chunk, i);
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yield return chunk;
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yield break;
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}
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chunk[i] = e.Current;
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}
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yield return chunk;
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}
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}
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}
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}

‎src/libraries/System.Linq/src/System/Linq/ThrowHelper.cs

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@@ -51,6 +51,7 @@ private static string GetArgumentString(ExceptionArgument argument)
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case ExceptionArgument.selector: return nameof(ExceptionArgument.selector);
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case ExceptionArgument.source: return nameof(ExceptionArgument.source);
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case ExceptionArgument.third: return nameof(ExceptionArgument.third);
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case ExceptionArgument.size: return nameof(ExceptionArgument.size);
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default:
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Debug.Fail("The ExceptionArgument value is not defined.");
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return string.Empty;
@@ -78,5 +79,6 @@ internal enum ExceptionArgument
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selector,
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source,
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third,
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size
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}
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}

‎src/libraries/System.Linq/tests/ChunkTests.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Collections.Generic;
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using Xunit;
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namespace System.Linq.Tests
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{
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public class ChunkTests : EnumerableTests
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{
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[Fact]
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public void ThrowsOnNullSource()
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{
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int[] source = null;
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AssertExtensions.Throws<ArgumentNullException>("source", () => source.Chunk(5));
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}
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[Theory]
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[InlineData(0)]
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[InlineData(-1)]
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public void ThrowsWhenSizeIsNonPositive(int size)
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{
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int[] source = {1};
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AssertExtensions.Throws<ArgumentOutOfRangeException>("size", () => source.Chunk(size));
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}
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[Fact]
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public void ChunkSourceLazily()
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{
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using IEnumerator<int[]> chunks = new FastInfiniteEnumerator<int>().Chunk(5).GetEnumerator();
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chunks.MoveNext();
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Assert.Equal(new[] {0, 0, 0, 0, 0}, chunks.Current);
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Assert.True(chunks.MoveNext());
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}
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private static IEnumerable<T> ConvertToType<T>(T[] array, Type type)
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{
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return type switch
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{
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{} x when x == typeof(TestReadOnlyCollection<T>) => new TestReadOnlyCollection<T>(array),
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{} x when x == typeof(TestCollection<T>) => new TestCollection<T>(array),
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{} x when x == typeof(TestEnumerable<T>) => new TestEnumerable<T>(array),
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_ => throw new Exception()
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};
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}
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[Theory]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2, -12345}, typeof(TestReadOnlyCollection<int>))]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2, -12345}, typeof(TestCollection<int>))]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2, -12345}, typeof(TestEnumerable<int>))]
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public void ChunkSourceRepeatCalls(int[] array, Type type)
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{
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IEnumerable<int> source = ConvertToType(array, type);
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Assert.Equal(source.Chunk(3), source.Chunk(3));
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}
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[Theory]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2, -12345}, typeof(TestReadOnlyCollection<int>))]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2, -12345}, typeof(TestCollection<int>))]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2, -12345}, typeof(TestEnumerable<int>))]
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public void ChunkSourceEvenly(int[] array, Type type)
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{
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IEnumerable<int> source = ConvertToType(array, type);
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using IEnumerator<int[]> chunks = source.Chunk(3).GetEnumerator();
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chunks.MoveNext();
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Assert.Equal(new[] {9999, 0, 888}, chunks.Current);
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chunks.MoveNext();
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Assert.Equal(new[] {-1, 66, -777}, chunks.Current);
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chunks.MoveNext();
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Assert.Equal(new[] {1, 2, -12345}, chunks.Current);
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Assert.False(chunks.MoveNext());
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}
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[Theory]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2}, typeof(TestReadOnlyCollection<int>))]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2}, typeof(TestCollection<int>))]
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[InlineData(new[] {9999, 0, 888, -1, 66, -777, 1, 2}, typeof(TestEnumerable<int>))]
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public void ChunkSourceUnevenly(int[] array, Type type)
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{
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IEnumerable<int> source = ConvertToType(array, type);
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using IEnumerator<int[]> chunks = source.Chunk(3).GetEnumerator();
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chunks.MoveNext();
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Assert.Equal(new[] {9999, 0, 888}, chunks.Current);
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chunks.MoveNext();
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Assert.Equal(new[] {-1, 66, -777}, chunks.Current);
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chunks.MoveNext();
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Assert.Equal(new[] {1, 2}, chunks.Current);
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Assert.False(chunks.MoveNext());
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}
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[Theory]
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[InlineData(new[] {9999, 0}, typeof(TestReadOnlyCollection<int>))]
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[InlineData(new[] {9999, 0}, typeof(TestCollection<int>))]
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[InlineData(new[] {9999, 0}, typeof(TestEnumerable<int>))]
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public void ChunkSourceSmallerThanMaxSize(int[] array, Type type)
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{
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IEnumerable<int> source = ConvertToType(array, type);
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using IEnumerator<int[]> chunks = source.Chunk(3).GetEnumerator();
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chunks.MoveNext();
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Assert.Equal(new[] {9999, 0}, chunks.Current);
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Assert.False(chunks.MoveNext());
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}
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[Theory]
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[InlineData(new int[] {}, typeof(TestReadOnlyCollection<int>))]
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[InlineData(new int[] {}, typeof(TestCollection<int>))]
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[InlineData(new int[] {}, typeof(TestEnumerable<int>))]
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public void EmptySourceYieldsNoChunks(int[] array, Type type)
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{
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IEnumerable<int> source = ConvertToType(array, type);
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using IEnumerator<int[]> chunks = source.Chunk(3).GetEnumerator();
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Assert.False(chunks.MoveNext());
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}
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[Fact]
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public void RemovingFromSourceBeforeIterating()
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{
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var list = new List<int>
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{
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9999, 0, 888, -1, 66, -777, 1, 2, -12345
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};
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IEnumerable<int[]> chunks = list.Chunk(3);
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list.Remove(66);
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Assert.Equal(new[] {new[] {9999, 0, 888}, new[] {-1, -777, 1}, new[] {2, -12345}}, chunks);
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}
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[Fact]
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public void AddingToSourceBeforeIterating()
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{
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var list = new List<int>
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{
137+
9999, 0, 888, -1, 66, -777, 1, 2, -12345
138+
};
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IEnumerable<int[]> chunks = list.Chunk(3);
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list.Add(10);
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Assert.Equal(new[] {new[] {9999, 0, 888}, new[] {-1, 66, -777}, new[] {1, 2, -12345}, new[] {10}}, chunks);
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}
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}
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}

‎src/libraries/System.Linq/tests/System.Linq.Tests.csproj

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<Compile Include="AsEnumerableTests.cs" />
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<Compile Include="AverageTests.cs" />
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<Compile Include="CastTests.cs" />
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<Compile Include="ChunkTests.cs" />
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<Compile Include="ConcatTests.cs" />
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<Compile Include="ConsistencyTests.cs" />
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<Compile Include="ContainsTests.cs" />

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