[geary/wip/713150-conversations] Fix soft assertion when EmailFlags is null in search predicate

[Jim Nelson <jnelson src gnome org>]

commit 5803a3d610eff59e23cae8caef95546d0c95a1a8
Author: Jim Nelson <jim yorba org>
Date:   Mon Mar 9 13:52:50 2015 -0700

    Fix soft assertion when EmailFlags is null in search predicate

 src/client/composer/composer-widget.vala     |    4 ++--
 src/engine/api/geary-account.vala            |    2 +-
 src/engine/app/app-conversation-monitor.vala |   15 +++++++++++----
 3 files changed, 14 insertions(+), 7 deletions(-)
---
diff --git a/src/client/composer/composer-widget.vala b/src/client/composer/composer-widget.vala
index da69c8b..a658622 100644
--- a/src/client/composer/composer-widget.vala
+++ b/src/client/composer/composer-widget.vala
@@ -651,8 +651,8 @@ public class ComposerWidget : Gtk.EventBox {
     // TODO: Folder blacklist
     // NOTE: This is called from a background thread.
     private bool local_search_predicate(Geary.EmailIdentifier email_id, Geary.Email.Field fields,
-        Gee.Collection<Geary.FolderPath?> known_paths, Geary.EmailFlags flags) {
-        return !flags.contains(Geary.EmailFlags.DRAFT);
+        Gee.Collection<Geary.FolderPath?> known_paths, Geary.EmailFlags? flags) {
+        return flags != null && !flags.contains(Geary.EmailFlags.DRAFT);
     }
     
     public async void restore_draft_state_async(Geary.Account account) {
diff --git a/src/engine/api/geary-account.vala b/src/engine/api/geary-account.vala
index f624274..0677592 100644
--- a/src/engine/api/geary-account.vala
+++ b/src/engine/api/geary-account.vala
@@ -68,7 +68,7 @@ public abstract class Geary.Account : BaseObject {
      * so use appropriate locking.
      */
     public delegate bool EmailSearchPredicate(Geary.EmailIdentifier email_id, Geary.Email.Field fields,
-        Gee.Collection<Geary.FolderPath?> known_paths, Geary.EmailFlags flags);
+        Gee.Collection<Geary.FolderPath?> known_paths, Geary.EmailFlags? flags);
     
     public Geary.AccountInformation information { get; protected set; }
     
diff --git a/src/engine/app/app-conversation-monitor.vala b/src/engine/app/app-conversation-monitor.vala
index 8308e9d..ec7bc94 100644
--- a/src/engine/app/app-conversation-monitor.vala
+++ b/src/engine/app/app-conversation-monitor.vala
@@ -48,9 +48,10 @@ public class Geary.App.ConversationMonitor : BaseObject {
             // Add "no folders" so we omit results that have been deleted permanently from the server.
             path_blacklist.add(null);
         }
+        
         // NOTE: This is called from a background thread.
         public bool search_predicate(EmailIdentifier email_id, Email.Field fields,
-            Gee.Collection<FolderPath?> known_paths, EmailFlags flags) {
+            Gee.Collection<FolderPath?> known_paths, EmailFlags? flags) {
             // don't want partial emails
             if (!fields.fulfills(required_fields))
                 return false;
@@ -61,7 +62,7 @@ public class Geary.App.ConversationMonitor : BaseObject {
                 return true;
             
             // Don't add drafts (unless in Drafts folder, above)
-            if (flags.contains(EmailFlags.DRAFT))
+            if (flags != null && flags.contains(EmailFlags.DRAFT))
                 return false;
             
             // If in a blacklisted path, don't add
@@ -658,13 +659,19 @@ public class Geary.App.ConversationMonitor : BaseObject {
         operation_queue.add(new FillWindowOperation(this, false));
     }
     
+    private bool is_folder_external_conversation_source(Folder folder) {
+        return !folder.path.equal_to(this.folder.path)
+            && !folder.properties.is_local_only
+            && !folder.properties.is_virtual;
+    }
+    
     private void on_account_email_added(Folder folder, Gee.Collection<EmailIdentifier> added_ids) {
-        if (!folder.path.equal_to(this.folder.path))
+        if (is_folder_external_conversation_source(folder))
             operation_queue.add(new ExternalAppendOperation(this, folder, added_ids));
     }
     
     private void on_account_email_removed(Folder folder, Gee.Collection<EmailIdentifier> removed_ids) {
-        if (folder.path.equal_to(this.folder.path))
+        if (!is_folder_external_conversation_source(folder))
             return;
         
         operation_queue.add(new ExternalRemoveOperation(this, folder, removed_ids));