fix: skip unresolvable assemblies during plugin discovery scan

BepInEx.Core/Bootstrap/BaseChainloader.cs

@@ -12,10 +12,10 @@
 
 namespace BepInEx.Bootstrap;
 
 public abstract class BaseChainloader<TPlugin>
 {
     protected static readonly string CurrentAssemblyName = Assembly.GetExecutingAssembly().GetName().Name;
     protected static readonly Version CurrentAssemblyVersion = Assembly.GetExecutingAssembly().GetName().Version;
     private static readonly Dictionary<string, bool> RefCache = new();
     private static Regex allowedGuidRegex { get; } = new(@"^[a-zA-Z0-9\._\-]+$");
 
@@ -101,13 +101,23 @@
 
         foreach (var r in ass.MainModule.AssemblyReferences)
         {
-            var dep = ass.MainModule.AssemblyResolver.Resolve(r);
+            AssemblyDefinition dep;
+            try
+            {
+                dep = ass.MainModule.AssemblyResolver.Resolve(r);
+            }
+            catch (AssemblyResolutionException ex)
+            {
+                // Dependency can't be resolved (e.g. framework facade like System.IO.Ports pulled in transitively via legacy libs). It can't reference this assembly, so skip the branch instead of failing discovery.
+                Logger.Log(LogLevel.Debug, $"Skipping unresolvable assembly reference '{r.FullName}' while checking '{ass.Name.FullName}': {ex.Message}");
+                continue;
+            }
             if (dep != null && ReferencesThisAssembly(dep, seen))
                 return RefCache[key] = true;
         }
         return RefCache[key] = false;
     }
     protected static bool HasBepinPlugins(AssemblyDefinition ass)
     {
         if (!ReferencesThisAssembly(ass))
             return false;