Exclude changes to unchangeable documents when applied in VS workspace

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

@@ -72,6 +72,8 @@ protected override void OnDocumentClosing(DocumentId documentId)
             }
         }
 
+        internal override bool IgnoreUnchangeableDocumentsWhenApplyingChanges => true;
+
         /// <summary>
         /// Returns the hierarchy for a given project. 
         /// </summary>

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

@@ -378,7 +378,8 @@ public override EnvDTE.FileCodeModel GetFileCodeModel(DocumentId documentId)
             var projectChanges = newSolution.GetChanges(currentSolution).GetProjectChanges().ToList();
 
             // 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).Concat(pd.GetChangedAdditionalDocuments())).Where(CanApplyChange).ToList();
+            var changedDocs = projectChanges.SelectMany(pd => pd.GetChangedDocuments(onlyGetDocumentsWithTextChanges: true).Concat(pd.GetChangedAdditionalDocuments()))
+                                            .Where(CanApplyChange).ToList();
             if (changedDocs.Count > 0)
             {
                 this.EnsureEditableDocuments(changedDocs);

src/Workspaces/Core/Portable/CodeActions/CodeAction.cs

@@ -225,7 +225,7 @@ protected async Task<Solution> PostProcessChangesAsync(Solution changedSolution,
             // process changed projects
             foreach (var projectChanges in solutionChanges.GetProjectChanges())
             {
-                var documentsToProcess = projectChanges.GetChangedDocuments(true).Concat(
+                var documentsToProcess = projectChanges.GetChangedDocuments(onlyGetDocumentsWithTextChanges: true).Concat(
                     projectChanges.GetAddedDocuments());
 
                 foreach (var documentId in documentsToProcess)

src/Workspaces/Core/Portable/Workspace/Solution/ProjectChanges.cs

@@ -132,9 +132,7 @@ public IEnumerable<DocumentId> GetAddedAnalyzerConfigDocuments()
         /// </summary>
         /// <returns></returns>
         public IEnumerable<DocumentId> GetChangedDocuments()
-        {
-            return GetChangedDocuments(false);
-        }
+            => GetChangedDocuments(onlyGetDocumentsWithTextChanges: false, ignoreUnchangeableDocuments: false);
 
         /// <summary>
         /// Get Changed Documents:
@@ -145,6 +143,9 @@ public IEnumerable<DocumentId> GetChangedDocuments()
         /// <param name="onlyGetDocumentsWithTextChanges"></param>
         /// <returns></returns>
         public IEnumerable<DocumentId> GetChangedDocuments(bool onlyGetDocumentsWithTextChanges)
+            => GetChangedDocuments(onlyGetDocumentsWithTextChanges, ignoreUnchangeableDocuments: false);
+
+        internal IEnumerable<DocumentId> GetChangedDocuments(bool onlyGetDocumentsWithTextChanges, bool ignoreUnchangeableDocuments)
         {
             foreach (var id in _newProject.DocumentIds)
             {
@@ -155,7 +156,7 @@ public IEnumerable<DocumentId> GetChangedDocuments(bool onlyGetDocumentsWithText
                 {
                     if (onlyGetDocumentsWithTextChanges)
                     {
-                        if (newState.HasTextChanged(oldState))
+                        if (newState.HasTextChanged(oldState, ignoreUnchangeableDocuments))
                             yield return id;
                     }
                     else

src/Workspaces/Core/Portable/Workspace/Solution/TextDocument.cs

@@ -129,9 +129,9 @@ internal virtual bool HasInfoChanged(TextDocument otherTextDocument)
         /// <summary>
         /// True if the text of the document change.
         /// </summary>
-        internal bool HasTextChanged(TextDocument otherTextDocument)
+        internal bool HasTextChanged(TextDocument otherTextDocument, bool ignoreUnchangeableDocument)
         {
-            return State.HasTextChanged(otherTextDocument.State);
+            return State.HasTextChanged(otherTextDocument.State, ignoreUnchangeableDocument);
         }
     }
 }

src/Workspaces/Core/Portable/Workspace/Solution/TextDocumentState.cs

@@ -375,10 +375,14 @@ public virtual async Task<VersionStamp> GetTopLevelChangeTextVersionAsync(Cancel
             return textAndVersion.Version;
         }
 
-        public bool HasTextChanged(TextDocumentState oldState)
+        public bool HasTextChanged(TextDocumentState oldState, bool ignoreUnchangeableDocument)
         {
-            return oldState.sourceText != sourceText
-                || oldState.TextAndVersionSource != TextAndVersionSource;
+            if (ignoreUnchangeableDocument && !oldState.CanApplyChange())
+            {
+                return false;
+            }
+
+            return oldState.TextAndVersionSource != TextAndVersionSource;
         }
 
         public bool HasInfoChanged(TextDocumentState oldState)

src/Workspaces/Core/Portable/Workspace/Workspace.cs

@@ -52,6 +52,8 @@ public abstract partial class Workspace : IDisposable
 
         internal bool TestHookPartialSolutionsDisabled { get; set; }
 
+        internal virtual bool IgnoreUnchangeableDocumentsWhenApplyingChanges { get; } = false;
+
         private Action<string>? _testMessageLogger;
 
         /// <summary>
@@ -1231,12 +1233,23 @@ private void CheckAllowedProjectChanges(ProjectChanges projectChanges)
                 throw new NotSupportedException(WorkspacesResources.Changing_document_property_is_not_supported);
             }
 
-            if (!this.CanApplyChange(ApplyChangesKind.ChangeDocument)
-                && projectChanges.GetChangedDocuments(onlyGetDocumentsWithTextChanges: true).Any())
+            var changedDocumentIds = projectChanges.GetChangedDocuments(onlyGetDocumentsWithTextChanges: true, IgnoreUnchangeableDocumentsWhenApplyingChanges).ToImmutableArray();
+
+            if (!this.CanApplyChange(ApplyChangesKind.ChangeDocument) && changedDocumentIds.Length > 0)
             {
                 throw new NotSupportedException(WorkspacesResources.Changing_documents_is_not_supported);
             }
 
+            // Checking for unchangeable documents will only be done if we were asked not to ignore them.
+            foreach (var documentId in changedDocumentIds)
+            {
+                var document = projectChanges.OldProject.GetDocumentState(documentId) ?? projectChanges.NewProject.GetDocumentState(documentId)!;
+                if (!document.CanApplyChange())
+                {
+                    throw new NotSupportedException(string.Format(WorkspacesResources.Changing_document_0_is_not_supported, document.FilePath ?? document.Name));
+                }
+            }
+
             if (projectChanges.GetAddedAdditionalDocuments().Any() && !this.CanApplyChange(ApplyChangesKind.AddAdditionalDocument))
             {
                 throw new NotSupportedException(WorkspacesResources.Adding_additional_documents_is_not_supported);
@@ -1296,15 +1309,6 @@ private void CheckAllowedProjectChanges(ProjectChanges projectChanges)
             {
                 throw new NotSupportedException(WorkspacesResources.Removing_analyzer_references_is_not_supported);
             }
-
-            foreach (var documentId in projectChanges.GetChangedDocuments())
-            {
-                var document = projectChanges.OldProject.GetDocumentState(documentId) ?? projectChanges.NewProject.GetDocumentState(documentId)!;
-                if (!document.CanApplyChange())
-                {
-                    throw new NotSupportedException(string.Format(WorkspacesResources.Changing_document_0_is_not_supported, document.FilePath ?? document.Name));
-                }
-            }
         }
 
         protected virtual bool CanApplyCompilationOptionChange(CompilationOptions oldOptions, CompilationOptions newOptions, Project project)
@@ -1452,8 +1456,8 @@ protected virtual void ApplyProjectChanges(ProjectChanges projectChanges)
             var oldDoc = projectChanges.OldProject.GetDocument(documentId)!;
             var newDoc = projectChanges.NewProject.GetDocument(documentId)!;
 
-            // update text if changed
-            if (newDoc.HasTextChanged(oldDoc))
+            // update text if it's changed (unless it's unchangeable and we were asked to exclude them)
+            if (newDoc.HasTextChanged(oldDoc, IgnoreUnchangeableDocumentsWhenApplyingChanges))
             {
                 // What we'd like to do here is figure out what actual text changes occurred and pass them on to the host.
                 // However, since it is likely that the change was done by replacing the syntax tree, getting the actual text changes is non trivial.

src/Workspaces/CoreTestUtilities/SolutionUtilities.cs

@@ -70,7 +70,7 @@ public static IEnumerable<DocumentId> GetTextChangedDocuments(Solution oldSoluti
             var projectsDifference = GetChangedProjectChanges(oldSolution, newSolution);
             foreach (var projectDifference in projectsDifference)
             {
-                changedDocuments.AddRange(projectDifference.GetChangedDocuments(true));
+                changedDocuments.AddRange(projectDifference.GetChangedDocuments(onlyGetDocumentsWithTextChanges: true));
             }
 
             return changedDocuments;