[balsa] Address book editor: do not crash

[Peter Bloomfield <peterb src gnome org>]

commit 5eb0835f13b9cbba4759b748210d2a753ef63ea0
Author: Peter Bloomfield <PeterBloomfield bellsouth net>
Date:   Tue Nov 26 20:21:57 2019 -0500

    Address book editor: do not crash
    
    if no address books are available for editing.
    
    * src/ab-main.c (bab_set_intial_address_book), (main): check for
      NULL address book list.

 ChangeLog     |  8 ++++++++
 src/ab-main.c | 26 ++++++++++++++++++--------
 2 files changed, 26 insertions(+), 8 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index e8c61621c..ac92b52bc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-11-26  Peter Bloomfield  <pbloomfield bellsouth net>
+
+       Address book editor: do not crash if no address books are
+       available for editing.
+
+       * src/ab-main.c (bab_set_intial_address_book), (main): check for
+       NULL address book list.
+
 2019-11-18  Peter Bloomfield  <pbloomfield bellsouth net>
 
        libbalsa_message_body_get_mime_type() is guaranteed to return a
diff --git a/src/ab-main.c b/src/ab-main.c
index 0588acaa3..963cb6ce2 100644
--- a/src/ab-main.c
+++ b/src/ab-main.c
@@ -1021,11 +1021,16 @@ static void
 bab_set_intial_address_book(LibBalsaAddressBook * ab,
                             GtkWidget           * window)
 {
-    GAction *action;
-
-    action =
-        g_action_map_lookup_action(G_ACTION_MAP(window), "address-book");
-    g_action_change_state(action, g_variant_new_string(libbalsa_address_book_get_name(ab)));
+    if (ab != NULL) {
+        GAction *action;
+
+        action =
+            g_action_map_lookup_action(G_ACTION_MAP(window),
+                                       "address-book");
+        g_action_change_state(action,
+                              g_variant_new_string
+                              (libbalsa_address_book_get_name(ab)));
+    }
 }
 
 GtkDialogFlags
@@ -1120,9 +1125,14 @@ main(int argc, char *argv[])
     libbalsa_conf_pop_group();
     libbalsa_conf_foreach_group(ADDRESS_BOOK_SECTION_PREFIX,
                                 bab_config_init, NULL);
-    ab = contacts_app.default_address_book ?
-        contacts_app.default_address_book :
-        contacts_app.address_book_list->data;
+    if (contacts_app.address_book_list == NULL) {
+        /* No address books found--why did we launch the editor? */
+        ab = NULL;
+    } else {
+        ab = contacts_app.default_address_book ?
+            contacts_app.default_address_book :
+            contacts_app.address_book_list->data;
+    }
 
     ab_window = bab_window_new(application);