fix UseDestinationValue with collection

src/Mapster.Tests/WhenUsingDestinationValue.cs

@@ -1,4 +1,6 @@
-using System.Linq.Expressions;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Shouldly;
 
@@ -10,20 +12,23 @@ public class WhenUsingDestinationValue
  [TestMethod]
  public void MapUsingDestinationValue()
  {
+ TypeAdapterConfig.GlobalSettings.Compiler = exp => exp.CompileWithDebugInfo();
  TypeAdapterConfig<Invoice, InvoiceDto>.NewConfig().TwoWays();
 
  var dto = new InvoiceDto
  {
  Id = 1,
  DocumentNumber = "AA001",
  SupplierCompany = "COM01",
- SupplierName = "Apple"
+ SupplierName = "Apple",
+ Numbers = Enumerable.Range(1, 5).ToList(),
  };
  var poco = dto.Adapt<Invoice>();
  poco.Id.ShouldBe(dto.Id);
  poco.DocumentNumber.ShouldBe("FOO");
  poco.Supplier.Name.ShouldBe(dto.SupplierName);
  poco.Supplier.Company.ShouldBe(dto.SupplierCompany);
+ poco.Numbers.ShouldBe(Enumerable.Range(1, 5));
  }
 
  public class ContractingParty
@@ -41,6 +46,9 @@ public class Invoice
 
  [UseDestinationValue]
  public ContractingParty Supplier { get; } = new ContractingParty();
+
+ [UseDestinationValue]
+ public ICollection<int> Numbers { get; } = new List<int>();
  }
 
  public class InvoiceDto
@@ -49,6 +57,7 @@ public class InvoiceDto
  public string DocumentNumber { get; set; }
  public string SupplierName { get; set; }
  public string SupplierCompany { get; set; }
+ public IEnumerable<int> Numbers { get; set; }
  }
  }
 }

src/Mapster/Adapters/ArrayAdapter.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
@@ -19,7 +20,26 @@ protected override bool CanMap(PreCompileArgument arg)
 
  protected override bool CanInline(Expression source, Expression? destination, CompileArgument arg)
  {
- return arg.MapType == MapType.Projection || ExpressionEx.CreateCountExpression(source) == null;
+ return arg.MapType == MapType.Projection;
+ }
+
+ protected override Expression TransformSource(Expression source)
+ {
+ if (ExpressionEx.CreateCountExpression(source) != null)
+ return source;
+ var transformed = source;
+ var elemType = source.Type.ExtractCollectionType();
+ var type = typeof(IEnumerable<>).MakeGenericType(elemType);
+ if (!type.IsAssignableFrom(source.Type))
+ {
+ var cast = typeof(Enumerable).GetMethod(nameof(Enumerable.Cast))!
+ .MakeGenericMethod(elemType);
+ transformed = Expression.Call(cast, transformed);
+ }
+
+ var toList = typeof(Enumerable).GetMethod(nameof(Enumerable.ToList))!
+ .MakeGenericMethod(elemType);
+ return Expression.Call(toList, transformed);
  }
 
  protected override Expression CreateInstantiationExpression(Expression source, Expression? destination, CompileArgument arg)
@@ -39,7 +59,12 @@ protected override Expression CreateBlockExpression(Expression source, Expressio
  {
  //Array.Copy(src, 0, dest, 0, src.Length)
  var method = typeof(Array).GetMethod("Copy", new[] { typeof(Array), typeof(int), typeof(Array), typeof(int), typeof(int) });
- return Expression.Call(method, source, Expression.Constant(0), destination, Expression.Constant(0), ExpressionEx.CreateCountExpression(source));
+ var len = arg.UseDestinationValue
+ ? Expression.Call(typeof(Math).GetMethod("Min", new[] {typeof(int), typeof(int)}),
+ ExpressionEx.CreateCountExpression(source), 
+ ExpressionEx.CreateCountExpression(destination))
+ : ExpressionEx.CreateCountExpression(source);
+ return Expression.Call(method, source, Expression.Constant(0), destination, Expression.Constant(0), len);
  }
 
  return CreateArraySet(source, destination, arg);

src/Mapster/Adapters/BaseAdapter.cs

@@ -111,6 +111,7 @@ protected virtual Expression CreateExpressionBody(Expression source, Expression?
 
  if (arg.Context.Running.Count > 1 && 
  !arg.Context.Config.SelfContainedCodeGeneration &&
+ !arg.UseDestinationValue &&
  !arg.Context.IsSubFunction())
  {
  if (destination == null)
@@ -195,7 +196,7 @@ protected Expression CreateBlockExpressionBody(Expression source, Expression? de
  transformedSource = src;
  }
  var set = CreateInstantiationExpression(transformedSource, destination, arg);
- if (destination != null && this.UseTargetValue && arg.GetConstructUsing()?.Parameters.Count != 2 && destination.CanBeNull())
+ if (destination != null && (this.UseTargetValue || arg.UseDestinationValue) && arg.GetConstructUsing()?.Parameters.Count != 2 && destination.CanBeNull())
  {
  //dest ?? new TDest();
  set = Expression.Coalesce(destination, set);

src/Mapster/Adapters/CollectionAdapter.cs

@@ -94,6 +94,13 @@ protected override Expression CreateBlockExpression(Expression source, Expressio
  actions.Add(ExpressionEx.Assign(list, destination)); //convert to list type
  }
 
+ //list.Clear();
+ if (arg.UseDestinationValue && arg.MapType == MapType.MapToTarget)
+ {
+ var clear = list.Type.GetMethod("Clear", Type.EmptyTypes);
+ actions.Add(Expression.Call(list, clear));
+ }
+
  actions.Add(CreateListSet(source, list, arg));
 
  if (shouldConvert)

src/Mapster/Adapters/DictionaryAdapter.cs

@@ -70,12 +70,10 @@ protected override Expression CreateBlockExpression(Expression source, Expressio
  : mapped;
  }
 
-
  //if (object.ReferenceEquals(source, destination))
  // return destination;
  LabelTarget? label = null;
- if (destination != null && 
- source.Type.IsObjectReference() &&
+ if (source.Type.IsObjectReference() &&
  destination.Type.IsObjectReference() &&
  (source.Type.IsAssignableFrom(destination.Type) || destination.Type.IsAssignableFrom(source.Type)))
  {
@@ -84,7 +82,6 @@ protected override Expression CreateBlockExpression(Expression source, Expressio
  actions.Add(Expression.IfThen(refEquals, Expression.Return(label, destination)));
  }
 
-
  var keyType = srcDictType.GetGenericArguments().First();
  var kvpType = source.Type.ExtractCollectionType();
  var kvp = Expression.Variable(kvpType, "kvp");

src/Mapster/Compile/CompileArgument.cs

@@ -14,6 +14,7 @@ public class CompileArgument
  public bool ExplicitMapping { get; set; }
  public TypeAdapterSettings Settings { get; set; }
  public CompileContext Context { get; set; }
+ public bool UseDestinationValue { get; set; }
 
  private HashSet<string>? _srcNames;
  internal HashSet<string> GetSourceNames()

src/Mapster/TypeAdapterConfig.cs

@@ -407,6 +407,7 @@ internal LambdaExpression CreateInlineMapExpression(Type sourceType, Type destin
  {
  arg.Settings.Resolvers.AddRange(mapping.NextResolvers);
  arg.Settings.Ignore.Apply(mapping.NextIgnore);
+ arg.UseDestinationValue = mapping.UseDestinationValue;
  }
 
  return CreateMapExpression(arg);