gdb: switch tuple object helpers to Python limited API equivalents

* PyTuple_GET_ITEM -> PyTuple_GetItem
* PyTuple_SET_ITEM -> PyTuple_SetItem
* PyTuple_GET_SIZE -> PyTuple_Size

Unlike PyTuple_SET_ITEM(), PyTuple_SetItem() returns an integer: 0 on
success and -1 on error (e.g. IndexError). The existing code must therefore
be updated to handle this new behaviour.

Since processing now stops when PyTuple_SetItem() returns an error, some
resources (such as newly allocated tuples) must be properly deallocated in
error paths. To address this, this patch replaces the use of raw 'PyObject *'
pointers with gdbpy_ref<>, a reference-counted wrapper around 'PyObject *',
which automatically decrements the reference count on early exit.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=23830
Approved-By: Tom Tromey <tom@tromey.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/gdb/python/py-function.c b/gdb/python/py-function.c
index 3bb81527a9c..23e0be0ea43 100644
--- a/gdb/python/py-function.c
+++ b/gdb/python/py-function.c
@@ -48,7 +48,8 @@ convert_values_to_python (int argc, struct value **argv)
       gdbpy_ref<> elt = value_to_value_object (argv[i]);
       if (elt == NULL)
 	return NULL;
-      PyTuple_SetItem (result.get (), i, elt.release ());
+      if (PyTuple_SetItem (result.get (), i, elt.release ()) < 0)
+	return nullptr;
     }
   return result;
 }