Bug 176107 row.__rownum cannot be directly used as group key
Create a table that bind it to a data set. Insert a group. For the Group On field, click on the "..." button to edit the expression, and select from "Availble Column Bindings" | "Table" | "RowNum". This creates a Group On Expression "row.__rownum". The resulting report design cannot be run. It produces error: Column binding "row.__rownum" does not exist. To workaround this, one must create another binding on the table and set its expression to "row.__rownum", then use the new binding as group key. This should not have been necessary. The "__rownum" binding should be implicitly available in all contexts that have a data set. E.g., it should be usable directly as group key, sort key, and in conditional format expressions, etc. Attached is a sample report that produces the error.
data/org.eclipse.birt.data.tests/test/org/eclipse/birt/data/engine/binding/GroupOnRowTest.java
sBuffer.append( metaData );
		sBuffer.append( "\n" );
		int groupCount = groupDefCount;
		while ( ri.next( ) )
		{
			String rowData = "";
			int startLevel = ri.getStartingGroupLevel( );
			if ( startLevel <= groupCount )
			{
				if ( startLevel == 0 )
					startLevel = 1;
				for ( int j = 0; j < startLevel - 1; j++ )
				{
					rowData += formatStr( "", expectedLen );
				}
				for ( int j = startLevel - 1; j < beArray.length; j++ )
				{
					String value;
					if(ri.getValue( beArray[j] )!=null)
						value = ri.getValue( beArray[j] ).toString( );
					else
						value = "null";
					
					rowData += formatStr( value, expectedLen );
				}
			}
			else
			{
				for ( int j = 0; j < groupCount; j++ )
				{