MetadataLoadContext assembly binding behavior is documented incorrectly
#113,353 opened on Mar 11, 2025
Repository metrics
- Stars
- (17,886 stars)
- PR merge metrics
- (Avg merge 12d 11h) (661 merged PRs in 30d)
Description
When MetadataLoadContext is resolving an assembly and its MetadataAssemblyResolver returns null, it throws an exception with this message:
https://github.com/dotnet/runtime/blob/a49ed697037bad503e32daa23f4339ebfb8962ea/src/libraries/System.Reflection.MetadataLoadContext/src/Resources/Strings.resx#L181
The message suggests that 'pre-loading' the assembly with LoadFromAssemblyPath will populate the MetadataLoadContext's assembly binding cache.
The API documentation for the LoadFrom methods also suggests this is the case:
MetadataLoadContext.LoadFromAssemblyPath Loads an assembly from a specific path on the disk and binds its assembly name to it in the MetadataLoadContext.
But these methods do not do this: https://github.com/dotnet/runtime/blob/a49ed697037bad503e32daa23f4339ebfb8962ea/src/libraries/System.Reflection.MetadataLoadContext/src/System/Reflection/MetadataLoadContext.Loading.cs#L47-L49
It looks like this behavior was changed, but the documentation and exception message was not updated: https://github.com/dotnet/runtime/commit/2ef74f6be9ac1a70902facdc4047c49682e75005#diff-7a38392b94b0c17ee62172e5b642b77f0b3a1bb8d79a6488d24f1729345c46fbL49