[epiphany/gnome-3-32] Broken web apps should crash in a nicer way

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 75f0212b8edbf1771cacc08a195546bee3e0df63
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Tue Jun 18 21:15:03 2019 +0000

    Broken web apps should crash in a nicer way
    
    Although #713 is fixed for new users, anyone who previously suffered
    from a broken web app migration is doomed to eternal crashes. We
    probably can't reasonably recover the broken profile dir, but we should
    at least try to warn users what is going on.
    
    
    (cherry picked from commit 53724537137c593076e9ca58add46387babdf16b)

 lib/ephy-settings.c | 36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)
---
diff --git a/lib/ephy-settings.c b/lib/ephy-settings.c
index 97e6a631a..f7e5ead69 100644
--- a/lib/ephy-settings.c
+++ b/lib/ephy-settings.c
@@ -89,15 +89,37 @@ ephy_settings_get (const char *schema)
   ephy_settings_init ();
 
   gsettings = g_hash_table_lookup (settings, schema);
-
-  if (gsettings == NULL) {
-    gsettings = g_settings_new (schema);
-    if (gsettings == NULL)
-      g_warning ("Invalid schema %s requested", schema);
-    else
-      g_hash_table_insert (settings, g_strdup (schema), gsettings);
+  if (gsettings)
+    return gsettings;
+
+  if (strcmp (schema, EPHY_PREFS_WEB_APP_SCHEMA) == 0) {
+    /* EPHY_PREFS_WEB_APP_SCHEMA won't be added to the settings table if the
+     * ephy_profile_dir_is_web_application() is FALSE. But we can still get
+     * here in EPHY_EMBED_SHELL_MODE_APPLICATION if the profile dir is broken
+     * such that its .app file is missing. This includes any web apps created by
+     * Epiphany 3.30 or earlier that were migrated to 3.32 before 3.32.3 before
+     * the main profile migration. This generally means anybody using Epiphany
+     * only for web apps has wound up with broken web apps after the migration.
+     *
+     * We can only crash, but it's nicer to crash here rather than crash later.
+     *
+     * https://gitlab.gnome.org/GNOME/epiphany/issues/713
+     */
+    g_error ("Epiphany is trying to access web app settings outside web app"
+             " mode. Your web app may be broken. If so, you must delete it and"
+             " recreate. See epiphany#713.");
   }
 
+  /* schema must not be relocatable, or g_settings_new() will crash. */
+  for (guint i = 0; i < G_N_ELEMENTS (ephy_prefs_relocatable_schemas); i++)
+    g_assert (strcmp (schema, ephy_prefs_relocatable_schemas[i].schema) != 0);
+
+  gsettings = g_settings_new (schema);
+  if (gsettings == NULL)
+    g_warning ("Invalid schema %s requested", schema);
+  else
+    g_hash_table_insert (settings, g_strdup (schema), gsettings);
+
   return gsettings;
 }