[epiphany/mcatanzaro/firefox-import] bookmarks-import: Fix error handling

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 42df42cc8a1c1fb1776130a1a84b495bdc753673
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Sun Oct 6 14:41:19 2019 -0500

    bookmarks-import: Fix error handling
    
    We need to, at minimum, use g_clear_error() to ensure it is NULL before
    passing it to g_set_error(). But it's simpler to use a separate GError
    for internal errors instead.
    
    Now instead of crashing, we'll show a nice error message "Firefox
    bookmarks could not be retrieved!" This isn't ideal, however, because
    clearly the code expects to trigger the earlier error message ("Close
    Firefox and try again") but is failing to do so.
    
    Fixes #965

 src/bookmarks/ephy-bookmarks-import.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)
---
diff --git a/src/bookmarks/ephy-bookmarks-import.c b/src/bookmarks/ephy-bookmarks-import.c
index 8862b995f..055bbe327 100644
--- a/src/bookmarks/ephy-bookmarks-import.c
+++ b/src/bookmarks/ephy-bookmarks-import.c
@@ -219,6 +219,7 @@ ephy_bookmarks_import_from_firefox (EphyBookmarksManager  *manager,
   GSequence *bookmarks = NULL;
   gboolean ret = TRUE;
   gchar *filename;
+  GError *my_error = NULL;
   const char *statement_str = "SELECT b.id, p.url, b.title, b.dateAdded, b.guid, g.title "
                               "FROM moz_bookmarks b "
                               "JOIN moz_places p ON b.fk=p.id "
@@ -235,10 +236,10 @@ ephy_bookmarks_import_from_firefox (EphyBookmarksManager  *manager,
                                NULL);
 
   connection = ephy_sqlite_connection_new (EPHY_SQLITE_CONNECTION_MODE_READ_ONLY, filename);
-  ephy_sqlite_connection_open (connection, error);
-  if (*error) {
-    g_warning ("Could not open database at %s: %s", filename, (*error)->message);
-    g_error_free (*error);
+  ephy_sqlite_connection_open (connection, &my_error);
+  if (my_error) {
+    g_warning ("Could not open database at %s: %s", filename, my_error->message);
+    g_error_free (my_error);
     g_set_error (error,
                  BOOKMARKS_IMPORT_ERROR,
                  BOOKMARKS_IMPORT_ERROR_BOOKMARKS,
@@ -248,10 +249,10 @@ ephy_bookmarks_import_from_firefox (EphyBookmarksManager  *manager,
 
   statement = ephy_sqlite_connection_create_statement (connection,
                                                        statement_str,
-                                                       error);
+                                                       &my_error);
   if (statement == NULL) {
-    g_warning ("Could not build bookmarks query statement: %s", (*error)->message);
-    g_error_free (*error);
+    g_warning ("Could not build bookmarks query statement: %s", my_error->message);
+    g_error_free (my_error);
     g_set_error (error,
                  BOOKMARKS_IMPORT_ERROR,
                  BOOKMARKS_IMPORT_ERROR_BOOKMARKS,
@@ -261,7 +262,7 @@ ephy_bookmarks_import_from_firefox (EphyBookmarksManager  *manager,
   }
 
   bookmarks = g_sequence_new (g_object_unref);
-  while (ephy_sqlite_statement_step (statement, error)) {
+  while (ephy_sqlite_statement_step (statement, &my_error)) {
     int bookmark_id = ephy_sqlite_statement_get_column_as_int (statement, 0);
     const char *url = ephy_sqlite_statement_get_column_as_string (statement, 1);
     const char *title = ephy_sqlite_statement_get_column_as_string (statement, 2);
@@ -281,9 +282,9 @@ ephy_bookmarks_import_from_firefox (EphyBookmarksManager  *manager,
     g_sequence_prepend (bookmarks, bookmark);
   }
 
-  if (*error) {
-    g_warning ("Could not execute bookmarks query statement: %s", (*error)->message);
-    g_error_free (*error);
+  if (my_error) {
+    g_warning ("Could not execute bookmarks query statement: %s", my_error->message);
+    g_error_free (my_error);
     g_set_error (error,
                  BOOKMARKS_IMPORT_ERROR,
                  BOOKMARKS_IMPORT_ERROR_BOOKMARKS,