From cc8755dc023ac51590f750ff7aa8f33367fcdd2c Mon Sep 17 00:00:00 2001
From: Anton Makeev <Anton.Makeev@jetbrains.com>
Date: Fri, 30 Nov 2012 15:23:01 +0100
Subject: [PATCH] Undo: fix 'cannot undo dummy file' (IDEA-92378)

---
 .../com/intellij/openapi/command/impl/CommandMerger.java  | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/platform/platform-impl/src/com/intellij/openapi/command/impl/CommandMerger.java b/platform/platform-impl/src/com/intellij/openapi/command/impl/CommandMerger.java
index cdd3b27502ef..d91cdacbbbb8 100644
--- a/platform/platform-impl/src/com/intellij/openapi/command/impl/CommandMerger.java
+++ b/platform/platform-impl/src/com/intellij/openapi/command/impl/CommandMerger.java
@@ -188,13 +188,17 @@ public class CommandMerger {
     Set<VirtualFile> affectedFiles = new HashSet<VirtualFile>();
     for (DocumentReference each : myAllAffectedDocuments) {
       VirtualFile file = each.getFile();
-      if (file == null || file instanceof LightVirtualFile) continue;
+      if (isVirtualDocumentChange(file)) continue;
       affectedFiles.add(file);
       if (affectedFiles.size() > 1) return true;
     }
     return false;
   }
 
+  private static boolean isVirtualDocumentChange(VirtualFile file) {
+    return file == null || file instanceof LightVirtualFile;
+  }
+
   public void undoOrRedo(FileEditor editor, boolean isUndo) {
     flushCurrentCommand();
 
@@ -235,7 +239,7 @@ public class CommandMerger {
   public boolean isPhysical() {
     if (myAllAffectedDocuments.isEmpty()) return false;
     for (DocumentReference each : myAllAffectedDocuments) {
-      if (each.getFile() == null) return false;
+      if (isVirtualDocumentChange(each.getFile())) return false;
     }
     return true;
   }