[glom] Write Python tracebacks to stderr.

[Murray Cumming <murrayc src gnome org>]

commit a2dfd16c7d1ad389a47c4769b9bfc4a90fb592b2
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Apr 5 15:28:38 2011 +0200

    Write Python tracebacks to stderr.
    
    	* glom/application.cc:
    	* glom/mode_data/box_data.cc:
    	* glom/mode_design/dialog_database_preferences.cc:
    	* tests/test_python_execute_script.cc: Output python errors to stderr as a
    	clue when things go wrong.

 ChangeLog                                       |   10 ++++++++++
 glom/application.cc                             |    5 +++++
 glom/mode_data/box_data.cc                      |    7 ++++++-
 glom/mode_design/dialog_database_preferences.cc |    5 +++++
 tests/test_python_execute_script.cc             |    5 +++++
 5 files changed, 31 insertions(+), 1 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index f27f41f..f5a10bf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-04-05  Murray Cumming  <murrayc murrayc com>
+
+	Write Python tracebacks to stderr.
+
+	* glom/application.cc:
+	* glom/mode_data/box_data.cc:
+	* glom/mode_design/dialog_database_preferences.cc:
+	* tests/test_python_execute_script.cc: Output python errors to stderr as a
+	clue when things go wrong.
+
 2011-04-04  Murray Cumming  <murrayc murrayc com>
 
 	Fix an error found by the gtkmm change to use operator const void*.
diff --git a/glom/application.cc b/glom/application.cc
index 7377145..c377a81 100644
--- a/glom/application.cc
+++ b/glom/application.cc
@@ -1281,6 +1281,11 @@ bool Application::on_document_load()
       sharedconnection->get_gda_connection(),
       callbacks,
       error_message);
+
+    if(!error_message.empty())
+    {
+      std::cerr << "Python Error: " << error_message << std::endl;
+    }
   }
 
 #ifndef GLOM_ENABLE_CLIENT_ONLY
diff --git a/glom/mode_data/box_data.cc b/glom/mode_data/box_data.cc
index edcb3cd..6e39aaa 100644
--- a/glom/mode_data/box_data.cc
+++ b/glom/mode_data/box_data.cc
@@ -30,6 +30,7 @@
 #include <glom/application.h>
 #include <algorithm> //For std::find()
 #include <libglom/libglom_config.h>
+#include <iostream>
 #include <glibmm/i18n.h>
 
 #ifdef GLOM_ENABLE_MAEMO
@@ -373,7 +374,7 @@ void Box_Data::execute_button_script(const sharedptr<const LayoutItem_Button>& l
     //Allow this UI to respond to UI change requests from the Python code:
     AppPythonUICallbacks callbacks;
 
-    Glib::ustring error_message; //TODO: Check this.
+    Glib::ustring error_message;
     glom_execute_python_function_implementation(layout_item->get_script(),
       field_values, //TODO: Maybe use the field's type here.
       get_document(),
@@ -381,6 +382,10 @@ void Box_Data::execute_button_script(const sharedptr<const LayoutItem_Button>& l
       sharedconnection->get_gda_connection(),
       callbacks,
       error_message);
+    if(!error_message.empty())
+    {
+      std::cerr << "Python Error: " << error_message << std::endl;
+    }
 }
 
 } //namespace Glom
diff --git a/glom/mode_design/dialog_database_preferences.cc b/glom/mode_design/dialog_database_preferences.cc
index 7d35f6c..c1ff40d 100644
--- a/glom/mode_design/dialog_database_preferences.cc
+++ b/glom/mode_design/dialog_database_preferences.cc
@@ -282,6 +282,11 @@ void Dialog_Database_Preferences::on_button_test_script()
     sharedconnection->get_gda_connection(),
     callbacks,
     error_message);
+
+  if(!error_message.empty())
+  {
+    std::cerr << "Python Error: " << error_message << std::endl;
+  }
 }
 
 
diff --git a/tests/test_python_execute_script.cc b/tests/test_python_execute_script.cc
index a51554d..125c8ae 100644
--- a/tests/test_python_execute_script.cc
+++ b/tests/test_python_execute_script.cc
@@ -94,6 +94,11 @@ int main()
     return EXIT_FAILURE;
   }
 
+  if(!error_message.empty())
+  {
+    std::cerr << "Python Error: " << error_message << std::endl;
+  }
+
   g_assert(error_message.empty());
 
   //Check that the callbacks received the expected values: