Add Mono-specific check for uninitialized default ALC on Resolving event (#35192)

Unlike the other resolvers, this one *can* exist on the default ALC, so we have to add the null check like in GetAssemblyLoadContext.

Move the now-unused ResolveUsingResolvingEvent method back to the CoreCLR-specific file.

diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.CoreCLR.cs b/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.CoreCLR.cs
index 9027e3b..7b49411 100644 (file)
--- a/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.CoreCLR.cs
+++ b/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.CoreCLR.cs
@@ -111,6 +111,15 @@ namespace System.Runtime.Loader
             return context.GetResolvedUnmanagedDll(assembly, unmanagedDllName);
         }
 
+        // This method is invoked by the VM to resolve an assembly reference using the Resolving event
+        // after trying assembly resolution via Load override and TPA load context without success.
+        private static Assembly? ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
+        {
+            AssemblyLoadContext context = (AssemblyLoadContext)(GCHandle.FromIntPtr(gchManagedAssemblyLoadContext).Target)!;
+            // Invoke the AssemblyResolve event callbacks if wired up
+            return context.ResolveUsingEvent(assemblyName);
+        }
+
         [DllImport(RuntimeHelpers.QCall, CharSet = CharSet.Unicode)]
         private static extern void LoadTypeForWinRTTypeNameInContextInternal(IntPtr ptrNativeAssemblyLoadContext, string typeName, ObjectHandleOnStack loadedType);
 

diff --git a/src/libraries/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs b/src/libraries/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs
index b709096..c958169 100644 (file)
--- a/src/libraries/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs
@@ -564,16 +564,6 @@ namespace System.Runtime.Loader
             return context.ResolveUsingLoad(assemblyName);
         }
 
-        // This method is invoked by the VM to resolve an assembly reference using the Resolving event
-        // after trying assembly resolution via Load override and TPA load context without success.
-        private static Assembly? ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
-        {
-            AssemblyLoadContext context = (AssemblyLoadContext)(GCHandle.FromIntPtr(gchManagedAssemblyLoadContext).Target)!;
-
-            // Invoke the AssemblyResolve event callbacks if wired up
-            return context.ResolveUsingEvent(assemblyName);
-        }
-
         // This method is invoked by the VM to resolve a satellite assembly reference
         // after trying assembly resolution via Load override without success.
         private static Assembly? ResolveSatelliteAssembly(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)

diff --git a/src/mono/netcore/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.Mono.cs b/src/mono/netcore/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.Mono.cs
index 60809d8..0fea776 100644 (file)
--- a/src/mono/netcore/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.Mono.cs
+++ b/src/mono/netcore/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.Mono.cs
@@ -117,7 +117,13 @@ namespace System.Runtime.Loader
         // success.
         private static Assembly? MonoResolveUsingResolvingEvent(IntPtr gchALC, string assemblyName)
         {
-            return ResolveUsingResolvingEvent(gchALC, new AssemblyName(assemblyName));
+            AssemblyLoadContext context;
+            // This check exists because the function can be called early in startup, before the default ALC is initialized
+            if (gchALC == IntPtr.Zero)
+                context = Default;
+            else
+                context = (AssemblyLoadContext)(GCHandle.FromIntPtr(gchALC).Target)!;
+            return context.ResolveUsingEvent(new AssemblyName(assemblyName));
         }
 
         // Invoked by Mono to resolve requests to load satellite assemblies.