[gimp/gimp-2-10] app: fix error propagation in boolean GUM grouping subexpressions

[Ell <ell src gnome org>]

commit ee01702fae0fb9413590b1783464a3f9feea1a0d
Author: Ell <ell_se yahoo com>
Date:   Fri Jun 12 01:33:24 2020 +0300

    app: fix error propagation in boolean GUM grouping subexpressions
    
    (cherry picked from commit bbc0f189535b3608a838fc7f2cbe8e141b6b2648)

 app/propgui/gimppropgui-eval.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/app/propgui/gimppropgui-eval.c b/app/propgui/gimppropgui-eval.c
index 308eeb2a15..719e500866 100644
--- a/app/propgui/gimppropgui-eval.c
+++ b/app/propgui/gimppropgui-eval.c
@@ -411,7 +411,10 @@ gimp_prop_eval_boolean_group (GObject      *config,
       result = gimp_prop_eval_boolean_or (config, pspec,
                                           expr, t, error, depth + 1);
 
-      if (! *error && g_strcmp0 (*t, ")"))
+      if (*error)
+        return FALSE;
+
+      if (g_strcmp0 (*t, ")"))
         {
           g_set_error (error, GIMP_PROP_EVAL_ERROR, GIMP_PROP_EVAL_FAILED,
                        "unterminated group");