[RFC] [python] Fix field list of typedef regression

[dje@google.com (Doug Evans)]

Hi.
This patch fixes a regression in the current tree.
The field list of a typedef went from the underlying field list
to an empty list.

Question: What's the right way to handle ref counting here?

2011-10-29  Doug Evans  <dje@google.com>

	* python/py-type.c (typy_fields_items): Call check_typedef.

	testsuite/
	* gdb.python/py-type.c (TS): New typedef.
	(ts): New global.
	* gdb.python/py-type.exp: Test field list of typedef.

Index: python/py-type.c
===================================================================
RCS file: /cvs/src/src/gdb/python/py-type.c,v
retrieving revision 1.27
diff -u -p -r1.27 py-type.c
--- python/py-type.c	27 Oct 2011 09:14:27 -0000	1.27
+++ python/py-type.c	29 Oct 2011 08:04:06 -0000
@@ -295,11 +295,24 @@ static PyObject *
 typy_fields_items (PyObject *self, enum gdbpy_iter_kind kind)
 {
   PyObject *result = NULL, *iter = NULL;
-  
+  volatile struct gdb_exception except;
+
+  TRY_CATCH (except, RETURN_MASK_ALL)
+    {
+      struct type *type = ((type_object *) self)->type;
+      struct type *checked_type = type;
+
+      CHECK_TYPEDEF (checked_type);
+      if (checked_type != type)
+        self = type_to_type_object (checked_type);
+      /* FIXME: reference counting of self? */
+    }
+  GDB_PY_HANDLE_EXCEPTION (except);
+
   iter = typy_make_iter (self, kind);
   if (iter == NULL)
     return NULL;
-    
+
   result = PySequence_List (iter);
   Py_DECREF (iter);
   return result;
Index: testsuite/gdb.python/py-type.c
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.python/py-type.c,v
retrieving revision 1.5
diff -u -p -r1.5 py-type.c
--- testsuite/gdb.python/py-type.c	28 Sep 2011 20:06:01 -0000	1.5
+++ testsuite/gdb.python/py-type.c	29 Oct 2011 08:04:06 -0000
@@ -21,6 +21,9 @@ struct s
   int b;
 };
 
+typedef struct s TS;
+TS ts;
+
 #ifdef __cplusplus
 struct C
 {
Index: testsuite/gdb.python/py-type.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.python/py-type.exp,v
retrieving revision 1.14
diff -u -p -r1.14 py-type.exp
--- testsuite/gdb.python/py-type.exp	28 Sep 2011 20:06:01 -0000	1.14
+++ testsuite/gdb.python/py-type.exp	29 Oct 2011 08:04:06 -0000
@@ -64,6 +64,10 @@ proc runto_bp {bp} {
 proc test_fields {lang} {
   global gdb_prompt
 
+  # .fields() of a typedef should still return the underlying field list
+  gdb_test "python print len(gdb.parse_and_eval('ts').type.fields())" "2" \
+      "$lang typedef field list"
+
   if {$lang == "c++"} {
       # Test usage with a class
       gdb_py_test_silent_cmd "print c" "print value" 1