pyuno: make extractUnoException handle exceptions raised by uno.py loading

This allows having a meaningful error message when extractUnoException
is called from pyuno_loader::getLoaderModule() (via
raiseRuntimeExceptionWhenNeeded()). If it is called to treat an error
that cropped up in loading uno.py, the old code would abort the whole
operation by throwing an exception because... it gets essentially the
same error. The new code leads to a sensible message on the Python
debug console.

pyuno/source/module/pyuno_runtime.cxx

@@ -1,4 +1,4 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* -*- Mode: C++; eval:(c-set-style "bsd"); tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
 /*************************************************************************
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
@@ -53,6 +53,7 @@ using com::sun::star::uno::TypeDescription;
 using com::sun::star::uno::Sequence;
 using com::sun::star::uno::Type;
 using com::sun::star::uno::UNO_QUERY;
+using com::sun::star::uno::Exception;
 using com::sun::star::uno::RuntimeException;
 using com::sun::star::uno::XComponentContext;
 using com::sun::star::lang::XSingleServiceFactory;
@@ -914,41 +915,56 @@ Any Runtime::pyObject2Any ( const PyRef & source, enum ConversionMode mode ) con
 
 Any Runtime::extractUnoException( const PyRef & excType, const PyRef &excValue, const PyRef &excTraceback) const
 {
-    PyRef str;
+    OUString str;
     Any ret;
     if( excTraceback.is() )
     {
-        PyRef unoModule( impl ? impl->cargo->getUnoModule() : 0 );
+        Exception e;
+        PyRef unoModule;
+        if ( impl )
+        {
+            try
+            {
+                unoModule = impl->cargo->getUnoModule();
+            }
+            catch (Exception ei)
+            {
+                e=ei;
+            }
+        }
         if( unoModule.is() )
         {
             PyRef extractTraceback(
                 PyDict_GetItemString(unoModule.get(),"_uno_extract_printable_stacktrace" ) );
 
-            if( extractTraceback.is() )
+            if( PyCallable_Check(extractTraceback.get()) )
             {
                 PyRef args( PyTuple_New( 1), SAL_NO_ACQUIRE );
                 PyTuple_SetItem( args.get(), 0, excTraceback.getAcquired() );
-                str = PyRef( PyObject_CallObject( extractTraceback.get(),args.get() ), SAL_NO_ACQUIRE);
+                PyRef pyStr( PyObject_CallObject( extractTraceback.get(),args.get() ), SAL_NO_ACQUIRE);
+                str = rtl::OUString::createFromAscii( PyString_AsString(pyStr.get()) );
             }
             else
             {
-                str = PyRef(
+                str = OUString(RTL_CONSTASCII_USTRINGPARAM("Couldn't find uno._uno_extract_printable_stacktrace"));
-                    PyString_FromString( "Couldn't find uno._uno_extract_printable_stacktrace" ),
-                    SAL_NO_ACQUIRE );
             }
         }
         else
         {
-            str = PyRef(
+            str = OUString(RTL_CONSTASCII_USTRINGPARAM("Could not load uno.py, no stacktrace available"));
-                PyString_FromString( "Couldn't find uno.py, no stacktrace available" ),
+            if ( e.Message.getLength() > 0 )
-                SAL_NO_ACQUIRE );
+            {
+                str += OUString (RTL_CONSTASCII_USTRINGPARAM(" (Error loading uno.py: "));
+                str += e.Message;
+                str += OUString (RTL_CONSTASCII_USTRINGPARAM(")"));
+            }
         }
 
     }
     else
     {
         // it may occur, that no traceback is given (e.g. only native code below)
-        str = PyRef( PyString_FromString( "no traceback available" ), SAL_NO_ACQUIRE);
+        str = OUString( RTL_CONSTASCII_USTRINGPARAM( "no traceback available" ) );
     }
 
     if( isInstanceOfStructOrException( excValue.get() ) )
@@ -978,9 +994,10 @@ Any Runtime::extractUnoException( const PyRef & excType, const PyRef &excValue,
             buf.appendAscii( "Couldn't convert exception value to a string" );
         }
         buf.appendAscii( ", traceback follows\n" );
-        if( str.is() )
+        if( str.getLength() > 0 )
         {
-            buf.appendAscii( PyString_AsString( str.get() ) );
+            buf.append( str );
+            buf.appendAscii( "\n" );
         }
         else
         {