When to migrate from PostSharp to Metalama

Before you migrate your code from PostSharp to Metalama, it is important to consider whether you should do it now. After all, PostSharp will still be maintained for several years, so you may have no time to migrate to Metalama now.

Avoid mixing PostSharp and Metalama in the same project

Mixing PostSharp and Metalama in the same project is in theory possible, but it is not recommended for the following reasons:

• Metalama, like PostSharp, introduces helper methods and properties, i.e., methods with no equivalent in source code. PostSharp, since it runs after Metalama, will see these helper declarations and the aspects will pick them as if they were user code, which could create incorrect and confusing situations.
• All Metalama aspects will be applied before any PostSharp aspect, just because Metalama runs before PostSharp. This limits the way you will be able to order aspects.
• We have not tested PostSharp with Metalama and will not investigate or address issues arising from the combined use of these products. In other words, this scenario is not supported.

Migrating is not an all-or-nothing decision

As a team or company, you can use both PostSharp and Metalama simultaneously. There is no need to take a global, company-wide decision to perform the migration.

You may keep using PostSharp for one product but migrate to Metalama for another. This may be a sound decision as long as these products have no dependencies that would result in a single C# project using both Metalama and PostSharp.

When to migrate to Metalama

Consider migrating to Metalama if:

• your project relies on a platform to which PostSharp will not be ported (for example, an ARM64 build environment or WinUI projects), or
• there are strong enough benefits to justify the migration effort. For details, see Benefits of Metalama over PostSharp.

DO NOT migrate to Metalama at the moment if:

• your project relies on a platform that is supported by PostSharp, but not by Metalama (for instance, a pre-2020 platform):

  • Visual Studio 2019 or earlier
  • .NET Standard 1.6 or earlier
  • .NET Framework 4.6 or earlier
  • Visual Basic (Metalama is available for C# projects only)

• your project relies on PostSharp features that have not yet been ported to Metalama. For details, see Status of the migration of PostSharp features to Metalama.

• your company has a large team on a business-critical mission with a tight deadline and therefore prefers the production-honed PostSharp (2008) over the relatively new Metalama (2023).