[gimp] libgimp: make sure GimpProcedures always get all their arguments

[Michael Natterer <mitch src gnome org>]

commit 5b8deb68b45fb2cb27fa7ed084c8a222604ad2c5
Author: Michael Natterer <mitch gimp org>
Date:   Sat Aug 3 16:56:31 2019 +0200

    libgimp: make sure GimpProcedures always get all their arguments
    
    gimp_procedure_run(): fill the value array with default values so a
    procedure's run callback always gets a complete value array. No more
    number-of-arguments checking in any new-style plug-in.

 libgimp/gimpprocedure.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)
---
diff --git a/libgimp/gimpprocedure.c b/libgimp/gimpprocedure.c
index c678d319d5..9cb8b03bbd 100644
--- a/libgimp/gimpprocedure.c
+++ b/libgimp/gimpprocedure.c
@@ -922,6 +922,7 @@ gimp_procedure_run (GimpProcedure  *procedure,
 {
   GimpValueArray *return_vals;
   GError         *error = NULL;
+  gint            i;
 
   g_return_val_if_fail (GIMP_IS_PROCEDURE (procedure), NULL);
   g_return_val_if_fail (args != NULL, NULL);
@@ -939,6 +940,18 @@ gimp_procedure_run (GimpProcedure  *procedure,
       return return_vals;
     }
 
+  /*  add missing args with default values  */
+  for (i = gimp_value_array_length (args); i < procedure->priv->n_args; i++)
+    {
+      GParamSpec *pspec = procedure->priv->args[i];
+      GValue      value = G_VALUE_INIT;
+
+      g_value_init (&value, G_PARAM_SPEC_VALUE_TYPE (pspec));
+      g_param_value_set_default (pspec, &value);
+      gimp_value_array_append (args, &value);
+      g_value_unset (&value);
+    }
+
   /*  call the procedure  */
   return_vals = procedure->priv->run_func (procedure, args,
                                            procedure->priv->run_data);