bpo-40334: Rename PyConfig.use_peg to _use_peg_parser (GH-19670)
* Rename PyConfig.use_peg to _use_peg_parser
* Document PyConfig._use_peg_parser and mark it a deprecated
* Mark -X oldparser option and PYTHONOLDPARSER env var as deprecated
in the documentation.
* Add use_old_parser() and skip_if_new_parser() to test.support
* Remove sys.flags.use_peg: use_old_parser() uses
_testinternalcapi.get_configs() instead.
* Enhance test_embed tests
* subprocess._args_from_interpreter_flags() copies -X oldparser
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 86fdf27..13600c2 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -326,7 +326,7 @@
if dev_mode:
args.extend(('-X', 'dev'))
for opt in ('faulthandler', 'tracemalloc', 'importtime',
- 'showrefcount', 'utf8'):
+ 'showrefcount', 'utf8', 'oldparser'):
if opt in xoptions:
value = xoptions[opt]
if value is True: