FluxMapper.SourceGenerator 1.0.0

FluxMapper

A next-generation object-mapping framework for .NET: an AutoMapper-shaped fluent API, backed by an adaptive execution engine that picks the fastest safe strategy available — a compile-time source generator when it can, a cached compiled-expression tier when it can't, and real IQueryable projection (ProjectTo<T>) for EF Core and friends — instead of committing to reflection or expression trees alone.

Status: v1.0.0. The API surface and execution engine are implemented and covered by an xunit test suite (69 tests), including a real Microsoft.EntityFrameworkCore.InMemory projection test and a real Native AOT publish smoke test. See "What's implemented" below.

Why another mapper

AutoMapper and Mapster both made real, different trade-offs: reflection-friendly configuration with a runtime cost, or source-generation speed with a narrower feature set. FluxMapper's premise is that you shouldn't have to choose up front — a single fluent configuration surface should let the engine pick the cheapest execution strategy that's actually safe for a given mapping:

• Flat, generator-friendly mappings compile to real C# at build time ([MapFrom] + FluxMapper.SourceGenerator) — zero reflection, zero Expression.Compile(), genuinely Native-AOT-safe.
• Everything else (nested objects, collections, dictionaries, polymorphism, cycles, custom resolvers) runs through a cached compiled-expression tier — still fast, but honestly annotated ([RequiresDynamicCode]/[RequiresUnreferencedCode]) as not AOT-safe, rather than silently breaking a trimmed or Native AOT app.
• Query translation (ProjectTo<TDestination>()) uses a separate, deliberately simpler expression builder so the result is safe to hand to a real IQueryable provider like EF Core, instead of the richer (but provider-opaque) shapes the runtime tier is free to use internally.

Quick start

using FluxMapper.Core.Configuration;

var config = MapperConfiguration.Create(cfg =>
{
    cfg.CreateMap<Order, OrderDto>();
    cfg.CreateMap<User, UserDto>();
});

config.AssertConfigurationIsValid(); // fail at startup, not in production

var mapper = config.CreateMapper();
var dto = mapper.Map<UserDto>(user);

Dependency injection (FluxMapper.Extensions.DependencyInjection):

services.AddFluxMapper(cfg => cfg.CreateMap<Order, OrderDto>());
// later: constructor-inject IMapper

EF Core / IQueryable projection — no EF-specific package needed, ProjectTo works against any IQueryable:

var dtos = await dbContext.Orders.ProjectTo<OrderDto>(config).ToListAsync();

AOT-safe generated mapping for a flat DTO:

[MapFrom(typeof(Order))]
public partial class OrderDto { public int Id { get; set; } public decimal Total { get; set; } }

var dto = OrderDto.MapFrom(order); // emitted at compile time, no IMapper involved

What's implemented

Packages

Installation

dotnet add package FluxMapper.Core
dotnet add package FluxMapper.SourceGenerator

Add FluxMapper.Extensions.DependencyInjection if you're using IServiceCollection, and FluxMapper.Analyzers for edit-time diagnostics on [MapFrom].

License

MIT — see LICENSE.