[geary] Avoid critical errors when addresses is null

[Robert Schroll <rschroll src gnome org>]

commit 35a7e9ff81c4efd1cfa3dfc553635df7514115c4
Author: Robert Schroll <rschroll gmail com>
Date:   Wed Jul 9 23:47:24 2014 -0400

    Avoid critical errors when addresses is null
    
    https://bugzilla.gnome.org/show_bug.cgi?id=732982

 src/client/composer/composer-widget.vala |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)
---
diff --git a/src/client/composer/composer-widget.vala b/src/client/composer/composer-widget.vala
index c502ff2..79f844c 100644
--- a/src/client/composer/composer-widget.vala
+++ b/src/client/composer/composer-widget.vala
@@ -1238,12 +1238,15 @@ public class ComposerWidget : Gtk.EventBox {
             compact_header_label.label = to_entry.buffer.text + (tocc ? ", " : "")
                 + cc_entry.buffer.text + (ccbcc ? ", " : "") + bcc_entry.buffer.text;
             StringBuilder tooltip = new StringBuilder();
-            foreach(Geary.RFC822.MailboxAddress addr in to_entry.addresses)
-                tooltip.append(_("To: ") + addr.get_full_address() + "\n");
-            foreach(Geary.RFC822.MailboxAddress addr in cc_entry.addresses)
-                tooltip.append(_("Cc: ") + addr.get_full_address() + "\n");
-            foreach(Geary.RFC822.MailboxAddress addr in bcc_entry.addresses)
-                tooltip.append(_("Bcc: ") + addr.get_full_address() + "\n");
+            if (to_entry.addresses != null)
+                foreach(Geary.RFC822.MailboxAddress addr in to_entry.addresses)
+                    tooltip.append(_("To: ") + addr.get_full_address() + "\n");
+            if (cc_entry.addresses != null)
+                foreach(Geary.RFC822.MailboxAddress addr in cc_entry.addresses)
+                    tooltip.append(_("Cc: ") + addr.get_full_address() + "\n");
+            if (bcc_entry.addresses != null)
+                foreach(Geary.RFC822.MailboxAddress addr in bcc_entry.addresses)
+                    tooltip.append(_("Bcc: ") + addr.get_full_address() + "\n");
             compact_header_label.tooltip_text = tooltip.str.slice(0, -1);  // Remove trailing \n
         }