[gnome-initial-setup/85-gnome-intial-setup-segfaults-possibly-due-to-locale-related-problems] language: don't crash if sort_key is NULL

[Will Thompson <wjt src gnome org>]

commit a6cdbfcf86620056d7d0cab6c14e1c60be30110a
Author: Will Thompson <will willthompson co uk>
Date:   Tue Oct 8 13:38:27 2019 +0100

    language: don't crash if sort_key is NULL
    
    On #85 we see the following backtrace, where the process has segfaulted:
    
        #0  0x00007f40bd849c02 in __strcmp_avx2 () at /usr/lib/libc.so.6
        #1  0x00007f40bd2c77cc in node_find_closest
            (haystack=0x563cd8093760, needle=needle@entry=0x563cd8093430, end=0x563cd7ef4590, 
iter_cmp=iter_cmp@entry=0x7f40bd2c7890 <iter_compare>, cmp_data=cmp_data@entry=0x7ffcbeb8bd10)
            at ../glib/glib/gsequence.c:1793
        #2  0x00007f40bd2c9f5f in node_insert_sorted
            (node=<optimized out>, new=new@entry=0x563cd8093430, end=<optimized out>, 
iter_cmp=iter_cmp@entry=0x7f40bd2c7890 <iter_compare>, cmp_data=cmp_data@entry=0x7ffcbeb8bd10) at 
../glib/glib/gsequence.c:2031
        #3  0x00007f40bd2cad96 in g_sequence_insert_sorted_iter (seq=0x563cd81225b0, data=<optimized out>, 
iter_cmp=iter_cmp@entry=0x7f40bd2c7890 <iter_compare>, cmp_data=cmp_data@entry=0x7ffcbeb8bd10)
            at ../glib/glib/gsequence.c:1047
        #4  0x00007f40bd2cae6d in g_sequence_insert_sorted (seq=<optimized out>, data=<optimized out>, 
cmp_func=<optimized out>, cmp_data=<optimized out>) at ../glib/glib/gsequence.c:740
        #5  0x00007f40bcd30b75 in gtk_list_box_insert () at /usr/lib/libgtk-3.so.0
        #6  0x00007f40bd3d3881 in g_cclosure_marshal_VOID__OBJECTv
            (closure=0x563cd7940f80, return_value=<optimized out>, instance=<optimized out>, args=<optimized 
out>, marshal_data=<optimized out>, n_params=<optimized out>, param_types=0x563cd7944b70)
            at ../glib/gobject/gmarshal.c:1910
        #7  0x00007f40bd3c3bba in _g_closure_invoke_va (param_types=0x563cd7944b70, n_params=<optimized out>, 
args=0x7ffcbeb8bf50, instance=0x563cd8124370, return_value=0x0, closure=0x563cd7940f80)
            at ../glib/gobject/gclosure.c:873
        #8  0x00007f40bd3c3bba in g_signal_emit_valist (instance=0x563cd8124370, signal_id=<optimized out>, 
detail=<optimized out>, var_args=var_args@entry=0x7ffcbeb8bf50) at ../glib/gobject/gsignal.c:3306
        #9  0x00007f40bd3c4868 in g_signal_emit (instance=<optimized out>, signal_id=<optimized out>, 
detail=<optimized out>) at ../glib/gobject/gsignal.c:3453
        #10 0x00007f40bcdf90ee in gtk_container_add () at /usr/lib/libgtk-3.so.0
        #11 0x0000563cd59f02e6 in add_one_language (chooser=chooser@entry=0x563cd7f50c40, 
locale_id=<optimized out>, is_initial=is_initial@entry=1)
            at ../gnome-initial-setup-3.34.0/gnome-initial-setup/pages/language/cc-language-chooser.c:258
    
    I believe the call to strcmp() here is from sort_languages(), since this
    is the sort_func for the list box in the language chooser widget; it's a
    tail call so I think the sort_languages() stack frame has been optimized
    away.
    
    LanguageWidget.sort_key is defined as:
    
        widget->sort_key = cc_util_normalize_casefold_and_unaccent (locale_name);
    
    locale_name is defined as:
    
        locale_name = gnome_get_language_from_locale (locale_id, locale_id);
    
    gnome_get_language_from_locale() may return NULL in various situations.
    In this particular case, it may be because the user has not installed
    various locales, or perhaps the iso-codes package (which provides the
    human-readable names that libgnome-desktop uses) is not installed.
    
    Replace the strcmp() call with g_strcmp0(), which can tolerate NULLs.
    Since we want to impose a total order on the list of languages, fall
    back to comparing locale_id. There's an argument that (a sort key
    derived from) locale_current_name or locale_untranslated_name – which
    are the name of the locale in the current locale and in the C locale
    respectively – should be considered first, but using the locale_id as a
    last resort seems fine anyway.

 gnome-initial-setup/pages/language/cc-language-chooser.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/gnome-initial-setup/pages/language/cc-language-chooser.c 
b/gnome-initial-setup/pages/language/cc-language-chooser.c
index d91f5cf..c4f4ed6 100644
--- a/gnome-initial-setup/pages/language/cc-language-chooser.c
+++ b/gnome-initial-setup/pages/language/cc-language-chooser.c
@@ -349,6 +349,7 @@ sort_languages (GtkListBoxRow *a,
                 gpointer       data)
 {
         LanguageWidget *la, *lb;
+        int ret;
 
         la = get_language_widget (gtk_bin_get_child (GTK_BIN (a)));
         lb = get_language_widget (gtk_bin_get_child (GTK_BIN (b)));
@@ -365,7 +366,11 @@ sort_languages (GtkListBoxRow *a,
         if (!la->is_extra && lb->is_extra)
                 return -1;
 
-        return strcmp (la->sort_key, lb->sort_key);
+        ret = g_strcmp0 (la->sort_key, lb->sort_key);
+        if (ret != 0)
+                return ret;
+
+        return g_strcmp0 (la->locale_id, lb->locale_id);
 }
 
 static void