add method to check if an open transaction is empty

This is needed to avoid to incorrectly abort a transaction if a recompute was done between opening and closing an editor in the property view

src/App/Document.cpp

@@ -1029,6 +1029,15 @@ bool Document::hasPendingTransaction() const
         return false;
 }
 
+bool Document::isTransactionEmpty() const
+{
+    if (d->activeUndoTransaction) {
+        return d->activeUndoTransaction->isEmpty();
+    }
+
+    return true;
+}
+
 void Document::clearUndos()
 {
     if (d->activeUndoTransaction)

src/App/Document.h

@@ -303,6 +303,9 @@ public:
     void abortTransaction();
     /// Check if a transaction is open
     bool hasPendingTransaction() const;
+    /// Check if a transaction is open and its list is empty.
+    /// If no transaction is open true is returned.
+    bool isTransactionEmpty() const;
     /// Set the Undo limit in Byte!
     void setUndoLimit(unsigned int UndoMemSize=0);
     /// Returns the actual memory consumption of the Undo redo stuff.

src/App/Transactions.cpp

@@ -110,6 +110,11 @@ void Transaction::Restore(Base::XMLReader &/*reader*/)
     assert(0);
 }
 
+bool Transaction::isEmpty() const
+{
+    return _Objects.empty();
+}
+
 int Transaction::getPos(void) const
 {
     return iPos;

src/App/Transactions.h

@@ -62,6 +62,8 @@ public:
     /// This method is used to restore properties from an XML document.
     virtual void Restore(Base::XMLReader &reader);
 
+    /// Returns true if the transaction list is empty; otherwise returns false.
+    bool isEmpty() const;
     /// get the position in the transaction history
     int getPos(void) const;
     /// check if this object is used in a transaction

src/Gui/propertyeditor/PropertyEditor.cpp

@@ -104,9 +104,12 @@ void PropertyEditor::closeEditor (QWidget * editor, QAbstractItemDelegate::EndEd
     if (autoupdate) {
         App::Document* doc = App::GetApplication().getActiveDocument();
         if (doc) {
-            if (doc->isTouched()) {
+            if (!doc->isTransactionEmpty()) {
                 doc->commitTransaction();
-                doc->recompute();
+                // Between opening and committing a transaction a recompute
+                // could already have been done
+                if (doc->isTouched())
+                    doc->recompute();
             }
             else {
                 doc->abortTransaction();