[glom] build_simple_where_expression(): Check input parameters.

[Murray Cumming <murrayc src gnome org>]

commit 9307a93de3bc892da1110274e112786d6e70d1c6
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Sep 29 11:24:17 2011 +0200

    build_simple_where_expression(): Check input parameters.
    
    	* glom/libglom/utils.cc: build_simple_where_expression(): Check for an
    	empty key field, which can happen during debugging.

 ChangeLog             |    7 +++++++
 glom/libglom/utils.cc |    6 ++++++
 2 files changed, 13 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 2b9ea39..63c9a3b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2011-09-29  Murray Cumming  <murrayc murrayc com>
 
+	build_simple_where_expression(): Check input parameters.
+
+	* glom/libglom/utils.cc: build_simple_where_expression(): Check for an 
+	empty key field, which can happen during debugging.
+
+2011-09-29  Murray Cumming  <murrayc murrayc com>
+
 	Glade utils: Catch generic exceptions.
 
 	* glom/glade_utils.h: Though this only happens when gtkmm has not been 
diff --git a/glom/libglom/utils.cc b/glom/libglom/utils.cc
index 78dae7c..f4f9763 100644
--- a/glom/libglom/utils.cc
+++ b/glom/libglom/utils.cc
@@ -450,6 +450,12 @@ Glib::RefPtr<Gnome::Gda::SqlBuilder> Utils::build_sql_select_with_key(const Glib
 
 Gnome::Gda::SqlExpr Utils::build_simple_where_expression(const Glib::ustring& table_name, const sharedptr<const Field>& key_field, const Gnome::Gda::Value& key_value)
 {
+  if(!key_field)
+  {
+    std::cerr << G_STRFUNC << ": key_field was empty" << std::endl;
+    return Gnome::Gda::SqlExpr();
+  }
+  
   Glib::RefPtr<Gnome::Gda::SqlBuilder> builder = Gnome::Gda::SqlBuilder::create(Gnome::Gda::SQL_STATEMENT_SELECT);
   builder->select_add_target(table_name);  //This might not be necessary.
   const Gnome::Gda::SqlBuilder::Id id = builder->add_cond(Gnome::Gda::SQL_OPERATOR_TYPE_EQ,