IDEA-175229 PSI changes should be reflected in the corresponding document even if PSI is non-physical

platform/core-impl/src/com/intellij/pom/core/impl/PomModelImpl.java

@@ -345,7 +345,7 @@ public class PomModelImpl extends UserDataHolderBase implements PomModel {
     }
 
     boolean physical = changeScope.isPhysical();
-    if (physical && synchronizer.toProcessPsiEvent()) {
+    if (synchronizer.toProcessPsiEvent()) {
       // fail-fast to prevent any psi modifications that would cause psi/document text mismatch
       // PsiToDocumentSynchronizer assertions happen inside event processing and are logged by PsiManagerImpl.fireEvent instead of being rethrown
       // so it's important to throw something outside event processing
@@ -353,7 +353,7 @@ public class PomModelImpl extends UserDataHolderBase implements PomModel {
         throw new IllegalStateException("Attempt to modify PSI for non-committed Document!");
       }
       CommandProcessor commandProcessor = CommandProcessor.getInstance();
-      if (!commandProcessor.isUndoTransparentActionInProgress() && commandProcessor.getCurrentCommand() == null) {
+      if (physical && !commandProcessor.isUndoTransparentActionInProgress() && commandProcessor.getCurrentCommand() == null) {
         throw new IncorrectOperationException("Must not change PSI outside command or undo-transparent action. See com.intellij.openapi.command.WriteCommandAction or com.intellij.openapi.command.CommandProcessor");
       }
     }

platform/core-impl/src/com/intellij/psi/impl/PsiToDocumentSynchronizer.java

@@ -115,7 +115,7 @@ public class PsiToDocumentSynchronizer extends PsiTreeChangeAdapter {
     return file.getUserData(PSI_DOCUMENT_ATOMIC_ACTION) == Boolean.TRUE;
   }
 
-  static void performAtomically(@NotNull PsiFile file, @NotNull Runnable runnable) {
+  public static void performAtomically(@NotNull PsiFile file, @NotNull Runnable runnable) {
     PsiUtilCore.ensureValid(file);
     assert !isInsideAtomicChange(file);
     file.putUserData(PSI_DOCUMENT_ATOMIC_ACTION, Boolean.TRUE);

platform/lang-impl/src/com/intellij/codeInsight/daemon/impl/DaemonListeners.java

@@ -370,7 +370,7 @@ public class DaemonListeners implements Disposable {
     if (project != null && project != myProject) return false;
     // cached is essential here since we do not want to create PSI file in alien project
     PsiFile psiFile = myPsiDocumentManager.getCachedPsiFile(document);
-    return psiFile != null && psiFile.getOriginalFile() == psiFile;
+    return psiFile != null && psiFile.isPhysical() && psiFile.getOriginalFile() == psiFile;
   }
 
   @Override

platform/lang-impl/src/com/intellij/pom/wrappers/PsiEventWrapperAspect.java

@@ -16,7 +16,11 @@
 
 package com.intellij.pom.wrappers;
 
+import com.intellij.injected.editor.VirtualFileWindow;
 import com.intellij.lang.ASTNode;
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.fileEditor.FileDocumentManager;
+import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.pom.PomModel;
 import com.intellij.pom.PomModelAspect;
 import com.intellij.pom.event.PomModelEvent;
@@ -27,11 +31,12 @@ import com.intellij.pom.tree.events.TreeChange;
 import com.intellij.pom.tree.events.TreeChangeEvent;
 import com.intellij.pom.tree.events.impl.ChangeInfoImpl;
 import com.intellij.pom.tree.events.impl.TreeChangeImpl;
+import com.intellij.psi.PsiDocumentManager;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
-import com.intellij.psi.impl.PsiManagerImpl;
-import com.intellij.psi.impl.PsiTreeChangeEventImpl;
-import com.intellij.psi.impl.source.SourceTreeToPsiMap;
+import com.intellij.psi.impl.*;
+import com.intellij.psi.impl.source.DummyHolder;
+import com.intellij.testFramework.LightVirtualFile;
 
 import java.util.Collections;
 
@@ -52,11 +57,12 @@ public class PsiEventWrapperAspect implements PomModelAspect{
 
   private static void sendAfterEvents(TreeChangeEvent changeSet) {
     ASTNode rootElement = changeSet.getRootElement();
-    final PsiFile file = (PsiFile)SourceTreeToPsiMap.treeElementToPsi(rootElement);
-    final PsiManagerImpl manager = (PsiManagerImpl)file.getManager();
+    PsiFile file = (PsiFile)rootElement.getPsi();
+    PsiManagerImpl manager = (PsiManagerImpl)file.getManager();
     if(manager == null) return;
 
     if (!file.isPhysical()) {
+      promoteNonPhysicalChangesToDocument(rootElement, file);
       manager.afterChange(false);
       return;
     }
@@ -120,6 +126,20 @@ public class PsiEventWrapperAspect implements PomModelAspect{
     }
   }
 
+  private static void promoteNonPhysicalChangesToDocument(ASTNode rootElement, PsiFile file) {
+    if (file instanceof DummyHolder) return;
+    if (((PsiDocumentManagerImpl)PsiDocumentManager.getInstance(file.getProject())).isCommitInProgress()) return;
+    
+    VirtualFile vFile = file.getViewProvider().getVirtualFile();
+    if (vFile instanceof LightVirtualFile && !(vFile instanceof VirtualFileWindow)) {
+      Document document = FileDocumentManager.getInstance().getCachedDocument(vFile);
+      if (document != null) {
+        CharSequence text = rootElement.getChars();
+        PsiToDocumentSynchronizer.performAtomically(file, () -> document.replaceString(0, document.getTextLength(), text));
+      }
+    }
+  }
+
   private static boolean checkPsiForChildren(final ASTNode[] affectedChildren) {
     for (final ASTNode astNode : affectedChildren) {
       //if (TreeUtil.isCollapsedChameleon(astNode)) return false;

platform/platform-impl/src/com/intellij/openapi/command/impl/DocumentUndoProvider.java

@@ -28,6 +28,7 @@ import com.intellij.openapi.fileEditor.FileDocumentManager;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.vfs.VirtualFile;
+import com.intellij.psi.SingleRootFileViewProvider;
 import org.jetbrains.annotations.Nullable;
 
 public class DocumentUndoProvider implements Disposable {
@@ -96,8 +97,10 @@ public class DocumentUndoProvider implements Disposable {
     private boolean shouldRecordActions(final Document document) {
       if (document.getUserData(UndoConstants.DONT_RECORD_UNDO) == Boolean.TRUE) return false;
 
-      final VirtualFile vFile = FileDocumentManager.getInstance().getFile(document);
-      return vFile == null || vFile.getUserData(UndoConstants.DONT_RECORD_UNDO) != Boolean.TRUE;
+      VirtualFile vFile = FileDocumentManager.getInstance().getFile(document);
+      if (vFile == null) return true;
+      return vFile.getUserData(SingleRootFileViewProvider.FREE_THREADED) != Boolean.TRUE && 
+             vFile.getUserData(UndoConstants.DONT_RECORD_UNDO) != Boolean.TRUE;
     }
 
     private void registerUndoableAction(DocumentEvent e) {