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fix: discover underlying mappings for nullable types #140

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fix: discover underlying mappings for nullable types #140

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6e0acec
fix: discover underlying mappings for nullable types
mjameson-se Jun 10, 2022
df610f7
add tests
mjameson-se Jun 10, 2022
d0a992c
fix warning
mjameson-se Jun 10, 2022
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29 changes: 23 additions & 6 deletions src/AutoMapper.Extensions.ExpressionMapping/MapperExtensions.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -265,12 +265,29 @@ private static bool HasUnderlyingType(this Type type)

private static void AddUnderlyingTypes(this Dictionary<Type, Type> typeMappings, IConfigurationProvider configurationProvider, Type sourceType, Type destType)
{
typeMappings.DoAddTypeMappings
(
configurationProvider,
!sourceType.HasUnderlyingType() ? new List<Type>() : ElementTypeHelper.GetElementTypes(sourceType).ToList(),
!destType.HasUnderlyingType() ? new List<Type>() : ElementTypeHelper.GetElementTypes(destType).ToList()
);
if (sourceType.IsNullableType() || destType.IsNullableType())
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Not a fan of adding literal types to typeMappings. Is there a chance of unwanted conversions?

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Since we're expressly checking below for a user-defined mapping between the two... It seems unlikely

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Probably need more tests. I suspect if you're mapping a LINQ select for a class like this one say you want some integers converted but not others then there may be problems.

{
Type underlyingSourceType = Nullable.GetUnderlyingType(sourceType) ?? sourceType;
Type underlyingDestType = Nullable.GetUnderlyingType(destType) ?? destType;
if (configurationProvider.Internal().ResolveTypeMap(underlyingSourceType, underlyingDestType) != null)
{
typeMappings.AddTypeMapping
(
configurationProvider,
underlyingSourceType,
underlyingDestType
);
}
}
else
{
typeMappings.DoAddTypeMappings
(
configurationProvider,
!sourceType.HasUnderlyingType() ? new List<Type>() : ElementTypeHelper.GetElementTypes(sourceType).ToList(),
!destType.HasUnderlyingType() ? new List<Type>() : ElementTypeHelper.GetElementTypes(destType).ToList()
);
}
}

/// <summary>
Expand Down
62 changes: 61 additions & 1 deletion tests/AutoMapper.Extensions.ExpressionMapping.UnitTests/XpressionMapper.Structs.Tests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using Xunit;

namespace AutoMapper.Extensions.ExpressionMapping.UnitTests
Expand Down Expand Up @@ -243,6 +242,37 @@ public void Can_map_local_variable_nullable_in_filter()
//Assert
Assert.NotNull(expMapped);
}

[Fact]
public void Can_map_struct_with_asymmetric_nullability()
{
// Arrange
var config = new MapperConfiguration(c =>
{
c.CreateMap<Instant, DateTimeOffset?>()
.ForMember(d => d.HasValue, c => c.MapFrom(_ => true))
.ConvertUsing(i => DateTimeOffset.FromUnixTimeSeconds(i.SecondsSinceUnixEpoch));
c.CreateMap<DateTimeOffset?, Instant>().ConvertUsing(d => d.HasValue ? new Instant { SecondsSinceUnixEpoch = d.Value.ToUnixTimeSeconds() } : default);
c.CreateMap<DateTimeOffset, Instant>().ConvertUsing(d => new Instant { SecondsSinceUnixEpoch = d.ToUnixTimeSeconds() });

c.CreateMap<ItemWithInstant, ItemWithDateTimeOffset>();
c.CreateMap<ItemWithDateTimeOffset, ItemWithInstant>();
});

config.AssertConfigurationIsValid();
var mapper = config.CreateMapper();
DateTimeOffset firstReleaseDate = DateTimeOffset.FromUnixTimeSeconds(0);
DateTimeOffset lastReleaseDate = DateTimeOffset.FromUnixTimeSeconds(10);
Expression<Func<ItemWithDateTimeOffset, bool>> exp = x => x.Date.HasValue && (x.Date >= firstReleaseDate && x.Date <= lastReleaseDate);

//Act
Expression<Func<ItemWithInstant, bool>> expMapped = mapper.MapExpression<Expression<Func<ItemWithInstant, bool>>>(exp);

//Assert
Assert.NotNull(expMapped);
Assert.True(expMapped.Compile()(new ItemWithInstant { Date = new Instant { SecondsSinceUnixEpoch = 7 } }));
Assert.False(expMapped.Compile()(new ItemWithInstant { Date = new Instant { SecondsSinceUnixEpoch = 12 } }));
}
}

public struct Source
Expand Down Expand Up @@ -460,6 +490,36 @@ public struct ItemWithDateLiteral
public DateTime Date { get; set; }
}

public struct ItemWithDateTimeOffset
{
public DateTimeOffset? Date { get; set; }
}

public struct ItemWithInstant
{
public Instant Date { get; set; }
}

public struct Instant
{
public long SecondsSinceUnixEpoch { get; set; }

public static bool operator >=(Instant self, Instant other) => self.SecondsSinceUnixEpoch >= other.SecondsSinceUnixEpoch;
public static bool operator <=(Instant self, Instant other) => self.SecondsSinceUnixEpoch <= other.SecondsSinceUnixEpoch;
public static bool operator !=(Instant self, Instant other) => self.SecondsSinceUnixEpoch != other.SecondsSinceUnixEpoch;
public static bool operator ==(Instant self, Instant other) => self.SecondsSinceUnixEpoch == other.SecondsSinceUnixEpoch;

public override bool Equals(object obj)
{
return obj is Instant instant && instant.SecondsSinceUnixEpoch == SecondsSinceUnixEpoch;
}

public override int GetHashCode()
{
return SecondsSinceUnixEpoch.GetHashCode();
}
}

static class Extensions
{
internal static ICollection<TModel> GetItems<TModel, TData>(this IQueryable<TData> query, IMapper mapper,
Expand Down