[gtk/wip/smcv/glib-2-74] Avoid repeated g_log_set_writer_func in tests

[Simon McVittie <smcv src gnome org>]

commit a4f45483b1203af66eb5b2de52118ecb754c0948
Author: Simon McVittie <smcv debian org>
Date:   Sat Aug 20 19:24:58 2022 +0100

    Avoid repeated g_log_set_writer_func in tests
    
    Since GLib 2.73.0 it can only be called once per process.
    
    Based on commit 78c153ae in GTK 4, but combining the icontheme test's
    two custom log writers into one log writer that serves both purposes,
    to avoid the need for a subprocess.
    
    Co-authored-by: Matthias Clasen <mclasen redhat com>
    Resolves: https://gitlab.gnome.org/GNOME/gtk/-/issues/5119

 testsuite/gtk/icontheme.c | 30 ++++++++++++------------------
 testsuite/gtk/treestore.c | 30 +++++++++++++-----------------
 2 files changed, 25 insertions(+), 35 deletions(-)
---
diff --git a/testsuite/gtk/icontheme.c b/testsuite/gtk/icontheme.c
index 7eed015ff2..1fdf3d12bd 100644
--- a/testsuite/gtk/icontheme.c
+++ b/testsuite/gtk/icontheme.c
@@ -121,6 +121,7 @@ assert_icon_lookup_fails (const char         *icon_name,
 }
 
 static GList *lookups = NULL;
+static gboolean collecting_lookups = FALSE;
 
 static GLogWriterOutput
 log_writer (GLogLevelFlags   log_level,
@@ -128,10 +129,17 @@ log_writer (GLogLevelFlags   log_level,
             gsize            n_fields,
             gpointer         user_data)
 {
+  gboolean *ignore_warnings = user_data;
   const char *domain = NULL;
   const char *msg = NULL;
   int i;
 
+  if (log_level == G_LOG_LEVEL_WARNING && *ignore_warnings)
+    return G_LOG_WRITER_HANDLED;
+
+  if (!collecting_lookups)
+    return g_log_writer_default (log_level, fields, n_fields, user_data);
+
   for (i = 0; i < n_fields; i++)
     {
       if (strcmp (fields[i].key, "GLIB_DOMAIN") == 0)
@@ -173,14 +181,14 @@ assert_lookup_order (const char         *icon_name,
 
   debug_flags = gtk_get_debug_flags ();
   gtk_set_debug_flags (debug_flags | GTK_DEBUG_ICONTHEME);
-  g_log_set_writer_func (log_writer, NULL, NULL);
+  collecting_lookups = TRUE;
 
   g_assert (lookups == NULL);
 
   info = gtk_icon_theme_lookup_icon (get_test_icontheme (FALSE), icon_name, size, flags);
   if (info)
     g_object_unref (info);
-  
+
   va_start (args, first);
   s = first;
   l = lookups;
@@ -197,7 +205,7 @@ assert_lookup_order (const char         *icon_name,
   g_list_free_full (lookups, g_free);
   lookups = NULL;
 
-  g_log_set_writer_func (g_log_writer_default, NULL, NULL);
+  collecting_lookups = FALSE;
   gtk_set_debug_flags (debug_flags);
 }
 
@@ -778,20 +786,6 @@ test_nonsquare_symbolic (void)
   g_object_unref (info);
 }
 
-static GLogWriterOutput
-log_writer_drop_warnings (GLogLevelFlags   log_level,
-                          const GLogField *fields,
-                          gsize            n_fields,
-                          gpointer         user_data)
-{
-  gboolean *ignore_warnings = user_data;
-
-  if (log_level == G_LOG_LEVEL_WARNING && *ignore_warnings)
-    return G_LOG_WRITER_HANDLED;
-
-  return g_log_writer_default (log_level, fields, n_fields, user_data);
-}
-
 int
 main (int argc, char *argv[])
 {
@@ -801,7 +795,7 @@ main (int argc, char *argv[])
 
   /* Ignore the one-time warning that the fallback icon theme can’t be found
    * (because we’ve changed the search paths). */
-  g_log_set_writer_func (log_writer_drop_warnings, &ignore_warnings, NULL);
+  g_log_set_writer_func (log_writer, &ignore_warnings, NULL);
   assert_icon_lookup_fails ("this-icon-totally-does-not-exist", 16, 0);
   ignore_warnings = FALSE;
 
diff --git a/testsuite/gtk/treestore.c b/testsuite/gtk/treestore.c
index 109b0dcb44..50126f65fe 100644
--- a/testsuite/gtk/treestore.c
+++ b/testsuite/gtk/treestore.c
@@ -1049,30 +1049,26 @@ specific_bug_77977 (void)
   g_object_unref (tree_store);
 }
 
-static GLogWriterOutput
-log_writer_drop_warnings (GLogLevelFlags   log_level,
-                          const GLogField *fields,
-                          gsize            n_fields,
-                          gpointer         user_data)
-{
-  return G_LOG_WRITER_HANDLED;
-}
-
 static void
 specific_bug_698396 (void)
 {
-  GtkTreeStore *tree_store;
-  gint new_order[1] = { 0 };
-
   g_test_bug ("698396");
 
-  tree_store = gtk_tree_store_new (1, G_TYPE_STRING);
+  if (g_test_subprocess ())
+    {
+      GtkTreeStore *tree_store;
+      int new_order[1] = { 0 };
 
-  g_log_set_writer_func (log_writer_drop_warnings, NULL, NULL);
-  gtk_tree_store_reorder (tree_store, NULL, new_order);
-  g_log_set_writer_func (g_log_writer_default, NULL, NULL);
+      tree_store = gtk_tree_store_new (1, G_TYPE_STRING);
+      gtk_tree_store_reorder (tree_store, NULL, new_order);
+      g_object_unref (tree_store);
 
-  g_object_unref (tree_store);
+      return;
+    }
+
+  g_test_trap_subprocess (NULL, 0, 0);
+  g_test_trap_assert_stderr ("*Cannot reorder, parent has no children*");
+  g_test_trap_assert_failed ();
 }
 
 /* main */