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/test/test_sys.py b/Lib/test/test_sys.py
index bd4ea47..91a645b 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -545,7 +545,7 @@
def test_sys_flags(self):
self.assertTrue(sys.flags)
attrs = ("debug",
- "inspect", "interactive", "optimize", "use_peg",
+ "inspect", "interactive", "optimize",
"dont_write_bytecode", "no_user_site", "no_site",
"ignore_environment", "verbose", "bytes_warning", "quiet",
"hash_randomization", "isolated", "dev_mode", "utf8_mode")