Improve exception handling related to PDBs and tree initialization

ILSpy/App.xaml.cs

@@ -191,7 +191,7 @@ namespace ICSharpCode.ILSpy
 		[ThreadStatic]
 		static bool showingError;
 
-		static void UnhandledException(Exception exception)
+		internal static void UnhandledException(Exception exception)
 		{
 			Debug.WriteLine(exception.ToString());
 			for (Exception ex = exception; ex != null; ex = ex.InnerException)

ILSpy/DebugInfo/PortableDebugInfoProvider.cs

@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Reflection.Metadata;
 
 using ICSharpCode.Decompiler.DebugInfo;
@@ -28,8 +29,8 @@ namespace ICSharpCode.Decompiler.PdbProvider
 	{
 		string pdbFileName;
 		string moduleFileName;
-
-		internal MetadataReaderProvider Provider { get; }
+		readonly MetadataReaderProvider provider;
+		bool hasError;
 
 		internal bool IsEmbedded => pdbFileName == null;
 
@@ -38,20 +39,54 @@ namespace ICSharpCode.Decompiler.PdbProvider
 		{
 			this.pdbFileName = pdbFileName;
 			this.moduleFileName = moduleFileName;
-			this.Provider = provider ?? throw new ArgumentNullException(nameof(provider));
+			this.provider = provider ?? throw new ArgumentNullException(nameof(provider));
+		}
+
+		public string Description {
+			get {
+				if (pdbFileName == null)
+				{
+					if (hasError)
+						return "Error while loading the PDB stream embedded in this assembly";
+					return "Embedded in this assembly";
+				}
+				else
+				{
+					if (hasError)
+						return $"Error while loading portable PDB: {pdbFileName}";
+					return $"Loaded from portable PDB: {pdbFileName}";
+				}
+			}
 		}
 
-		public string Description => pdbFileName == null
-			? "Embedded in this assembly"
-			: $"Loaded from portable PDB: {pdbFileName}";
+		internal MetadataReader GetMetadataReader()
+		{
+			try
+			{
+				hasError = false;
+				return provider.GetMetadataReader();
+			}
+			catch (BadImageFormatException)
+			{
+				hasError = true;
+				return null;
+			}
+			catch (IOException)
+			{
+				hasError = true;
+				return null;
+			}
+		}
 
 		public string SourceFileName => pdbFileName ?? moduleFileName;
 
 		public IList<DebugInfo.SequencePoint> GetSequencePoints(MethodDefinitionHandle method)
 		{
-			var metadata = Provider.GetMetadataReader();
+			var metadata = GetMetadataReader();
 			var debugInfo = metadata.GetMethodDebugInformation(method);
-			var sequencePoints = new List<Decompiler.DebugInfo.SequencePoint>();
+			var sequencePoints = new List<DebugInfo.SequencePoint>();
+			if (metadata == null)
+				return sequencePoints;
 
 			foreach (var point in debugInfo.GetSequencePoints())
 			{
@@ -82,8 +117,10 @@ namespace ICSharpCode.Decompiler.PdbProvider
 
 		public IList<Variable> GetVariables(MethodDefinitionHandle method)
 		{
-			var metadata = Provider.GetMetadataReader();
+			var metadata = GetMetadataReader();
 			var variables = new List<Variable>();
+			if (metadata == null)
+				return variables;
 
 			foreach (var h in metadata.GetLocalScopes(method))
 			{
@@ -100,8 +137,10 @@ namespace ICSharpCode.Decompiler.PdbProvider
 
 		public bool TryGetName(MethodDefinitionHandle method, int index, out string name)
 		{
-			var metadata = Provider.GetMetadataReader();
+			var metadata = GetMetadataReader();
 			name = null;
+			if (metadata == null)
+				return false;
 
 			foreach (var h in metadata.GetLocalScopes(method))
 			{

ILSpy/TreeNodes/AssemblyTreeNode.cs

@@ -181,14 +181,21 @@ namespace ICSharpCode.ILSpy.TreeNodes
 				// if we crashed on loading, then we don't have any children
 				return;
 			}
-			if (loadResult.PEFile != null)
+			try
 			{
-				LoadChildrenForPEFile(loadResult.PEFile);
+				if (loadResult.PEFile != null)
+				{
+					LoadChildrenForPEFile(loadResult.PEFile);
+				}
+				else if (loadResult.Package != null)
+				{
+					var package = loadResult.Package;
+					this.Children.AddRange(PackageFolderTreeNode.LoadChildrenForFolder(package.RootFolder));
+				}
 			}
-			else if (loadResult.Package != null)
+			catch (Exception ex)
 			{
-				var package = loadResult.Package;
-				this.Children.AddRange(PackageFolderTreeNode.LoadChildrenForFolder(package.RootFolder));
+				App.UnhandledException(ex);
 			}
 		}
 
@@ -198,9 +205,10 @@ namespace ICSharpCode.ILSpy.TreeNodes
 			var assembly = (MetadataModule)typeSystem.MainModule;
 			this.Children.Add(new Metadata.MetadataTreeNode(module, this));
 			Decompiler.DebugInfo.IDebugInfoProvider debugInfo = LoadedAssembly.GetDebugInfoOrNull();
-			if (debugInfo is Decompiler.PdbProvider.PortableDebugInfoProvider ppdb)
+			if (debugInfo is Decompiler.PdbProvider.PortableDebugInfoProvider ppdb
+				&& ppdb.GetMetadataReader() is System.Reflection.Metadata.MetadataReader reader)
 			{
-				this.Children.Add(new Metadata.DebugMetadataTreeNode(module, ppdb.IsEmbedded, ppdb.Provider.GetMetadataReader(), this));
+				this.Children.Add(new Metadata.DebugMetadataTreeNode(module, ppdb.IsEmbedded, reader, this));
 			}
 			this.Children.Add(new ReferenceFolderTreeNode(module, this));
 			if (module.Resources.Any())