Merge pull request #30675 from jasonmalinowski/fix-tryapplychanges-modifying-additional-files

Fix crash when applying code fixes that modify additional files

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspace.cs

@@ -85,7 +85,9 @@ protected override void OnDocumentClosing(DocumentId documentId)
 
         public virtual string GetFilePath(DocumentId documentId)
         {
-            return CurrentSolution.GetDocument(documentId)?.FilePath;
+            var solution = CurrentSolution;
+
+            return (solution.GetDocument(documentId) ?? solution.GetAdditionalDocument(documentId))?.FilePath;
         }
 
         /// <summary>

src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs

@@ -267,7 +267,7 @@ internal IVisualStudioHostDocument GetHostDocument(DocumentId documentId)
             }
 
             // first make sure we can edit the document we will be updating (check them out from source control, etc)
-            var changedDocs = projectChanges.SelectMany(pd => pd.GetChangedDocuments(true)).ToList();
+            var changedDocs = projectChanges.SelectMany(pd => pd.GetChangedDocuments(true).Concat(pd.GetChangedAdditionalDocuments())).ToList();
             if (changedDocs.Count > 0)
             {
                 this.EnsureEditableDocuments(changedDocs);