[gegl] operation: fix operation-class keys hash aliasing in subclasses

[Ell <ell src gnome org>]

commit e700c1e0015e9d68d8d76647c76e4cc3a6cb1798
Author: Ell <ell_se yahoo com>
Date:   Sun Jul 21 01:37:37 2019 +0300

    operation: fix operation-class keys hash aliasing in subclasses
    
    Since we no longer initialize the the keys hash table for each
    GeglOperation subclass in base_init(), it is inherited from the
    parent class; if the parent class already set some class keys, the
    inherited hash table is not NULL, and aliases that of the parent.
    
    Hackishly fix this by storing a pointer to the owner class in the
    hash table, and create a new hash table, rather than using the
    existing one, in case the stored pointer doesn't match the current
    class.

 gegl/operation/gegl-operation.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
---
diff --git a/gegl/operation/gegl-operation.c b/gegl/operation/gegl-operation.c
index d12858b2e..39e6ba6e3 100644
--- a/gegl/operation/gegl-operation.c
+++ b/gegl/operation/gegl-operation.c
@@ -744,11 +744,18 @@ gegl_operation_class_set_key (GeglOperationClass *klass,
       gegl_operation_class_register_name (klass, key_value, TRUE);
     }
 
-  if (! klass->keys)
+  if (! klass->keys ||
+      /* avoid inheriting an existing hash table from the parent class */
+      g_hash_table_lookup (klass->keys, "operation-class") != klass)
     {
       /* XXX: leaked for now */
       klass->keys = g_hash_table_new_full (g_str_hash, g_str_equal,
                                            g_free, g_free);
+
+      /* ... so we don't actually have to worry about these values being
+       * freed ...
+       */
+      g_hash_table_insert (klass->keys, "operation-class", klass);
     }
 
   g_hash_table_insert (klass->keys, g_strdup (key_name),