[Breaking change]: * is no longer accepted as a wildcard attribute value in assembly names

[jkotas]

Description

(This breaking is documented retrospectively based on 1P customer feedback.)

Assembly names allowed specifying * as a wildcard value for attribute value that was equivalent to not specifying the value at all. This undocumented feature was removed in .NET 7.

Version

Other (please put exact version in description textbox)

Previous behavior

* can be specified as a value for assembly name attribute. For example, Assembly.Load("System.Runtime, Version=*, PublicKeyToken=*") succeeds. It has identical behavior as not specifying the attribute value at all Assembly.Load("System.Runtime").

New behavior

Assembly.Load("System.Runtime, Version=*, PublicKeyToken=*") fails with FileLoadException with "The given assembly name was invalid." error message.

Type of breaking change

• Binary incompatible: Existing binaries might encounter a breaking change in behavior, such as failure to load or execute, and if so, require recompilation.
• Source incompatible: When recompiled using the new SDK or component or to target the new runtime, existing source code might require source changes to compile successfully.
• Behavioral change: Existing binaries might behave differently at run time.

Reason for change

This was undocumented feature and it was not consistent implemented by all .NET assembly name parsers. The undocumented feature was removed to unify the behavior of assembly name parsing throughout .NET.

Recommended action

Omit assembly name attributes with wildcard value. For example, change System.Runtime, Version=* to just System.Runtime.

Feature area

Core .NET libraries

Affected APIs

• System.Reflection.Assembly.Load(string assemblyString)
• Type.GetType (all overloads)
• AssemblyName..ctor(string assemblyName)