[epiphany/mcatanzaro/#887] session: never save before first successful page load

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 886f2ffcf7ddf17825136e52e19588442bcdfa36
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sat Dec 14 13:52:32 2019 -0600

    session: never save before first successful page load
    
    If WebKit is somehow so broken that it can't load any pages, we
    currently overwrite the session state file with empty state, deleting
    all the user's saved tabs. That's not very friendly.
    
    Fixes #887

 src/ephy-session.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)
---
diff --git a/src/ephy-session.c b/src/ephy-session.c
index 2c804a048..bcf17b297 100644
--- a/src/ephy-session.c
+++ b/src/ephy-session.c
@@ -64,6 +64,7 @@ struct _EphySession {
   GCancellable *save_cancellable;
   guint closing : 1;
   guint dont_save : 1;
+  guint loaded_page : 1;
 };
 
 #define SESSION_STATE           "type:session_state"
@@ -122,8 +123,13 @@ load_changed_cb (WebKitWebView   *view,
                  WebKitLoadEvent  load_event,
                  EphySession     *session)
 {
-  if (!ephy_web_view_load_failed (EPHY_WEB_VIEW (view)))
-    ephy_session_save (session);
+  if (ephy_web_view_load_failed (EPHY_WEB_VIEW (view)))
+    return;
+
+  if (load_event == WEBKIT_LOAD_FINISHED)
+    session->loaded_page = TRUE;
+
+  ephy_session_save (session);
 }
 
 static void
@@ -887,14 +893,6 @@ save_session_sync (GTask        *task,
   GList *w;
   int ret = -1;
 
-  /* If any web view has an insane URL, then something has probably gone wrong
-   * inside WebKit. For instance, if the web process is nonfunctional, the UI
-   * process could have an invalid URI property. Yes, this would be a WebKit
-   * bug, but Epiphany should be robust to such issues. Do not clobber an
-   * existing good session file with our new bogus state. Bug #768250. */
-  if (!session_seems_sane (data->windows))
-    return;
-
   buffer = xmlBufferCreate ();
   writer = xmlNewTextWriterMemory (buffer, 0);
   if (writer == NULL)
@@ -986,6 +984,19 @@ ephy_session_save_idle_cb (EphySession *session)
 
   session->save_source_id = 0;
 
+  /* If we have never successfully loaded any page, or any web view has an
+   * insane URL, then something has probably gone wrong inside WebKit. For
+   * instance, if the web process is nonfunctional, the UI process could have
+   * an invalid URI property. Yes, this would be a WebKit bug, but Epiphany
+   * should be robust to such issues. Do not clobber an existing good session
+   * file with our new bogus state. Bug #768250.
+   */
+  data = save_data_new (session);
+  if (!session->loaded_page || !session_seems_sane (data->windows)) {
+    save_data_free (data);
+    return G_SOURCE_REMOVE;
+  }
+
   if (session->save_cancellable) {
     g_cancellable_cancel (session->save_cancellable);
     g_object_unref (session->save_cancellable);
@@ -1001,7 +1012,6 @@ ephy_session_save_idle_cb (EphySession *session)
 
   g_application_hold (G_APPLICATION (ephy_shell_get_default ()));
   session->save_cancellable = g_cancellable_new ();
-  data = save_data_new (session);
   task = g_task_new (session, session->save_cancellable,
                      save_session_in_thread_finished_cb, NULL);
   g_task_set_task_data (task, data, (GDestroyNotify)save_data_free);