Currently (135c6a56e55d2f4f8718b3b9f03ce3c692b15f0f) the following test fails:./python -m test.regrtest -v test_tools.test_unparse -u cpu(Note that -u cpu is needed to force test_unparse.DirectoryTestCase to check all files under Lib/ andLib/test/.)An example error message:======================================================================FAIL: test_files (test.test_tools.test_unparse.DirectoryTestCase) (filename='/home/yen/Projects/cpython/Lib/test/test_typing.py')----------------------------------------------------------------------Traceback (most recent call last):  File "/home/yen/Projects/cpython/Lib/test/test_tools/test_unparse.py", line 309, in test_files    self.check_roundtrip(source)  File "/home/yen/Projects/cpython/Lib/test/test_tools/test_unparse.py", line 132, in check_roundtrip    self.assertASTEqual(ast1, ast2)  File "/home/yen/Projects/cpython/Lib/test/test_tools/test_unparse.py", line 124, in assertASTEqual    self.assertEqual(ast.dump(ast1), ast.dump(ast2))AssertionError: 'Modu[88178 chars]kind=\'u\')], ctx=Load())), ctx=Load()))], dec[421987 chars]=[])' != 'Modu[88178 chars]kind=None)], ctx=Load())), ctx=Load()))], deco[421986 chars]=[])'----------------------------------------------------------------------Apparently that's becauseTools/parser/unparse.py does not handle strings like u"bar" correctly. I managed to "fix" it with the following patch:diff --git a/Tools/parser/unparse.py b/Tools/parser/unparse.pyindex385902ef4b..a25b5e49df 100644--- a/Tools/parser/unparse.py+++ b/Tools/parser/unparse.py@@ -399,6 +399,8 @@ class Unparser:         elif value is ...:             self.write("...")         else:+            if t.kind == 'u':+                self.write("u")             self._write_constant(t.value)     def _List(self, t):Not sure if this is the correct approach, though.

On the other hand, if this causes troubles, feel free to just replace u"bar" with "bar" in that test. It is not really important.

Please submit a PR.

After readingPython/ast.c, I think my patch is correct, so I submitted it to GitHub ashttps://github.com/python/cpython/pull/13583 :)

New changesetaaf47caf35984e614d93bd8bea5227df55e0e3e6 by Miss Islington (bot) (Chih-Hsuan Yen) in branch 'master':bpo-37053: handle strings like u"bar" correctly inTools/parser/unparse.py (GH-13583)https://github.com/python/cpython/commit/aaf47caf35984e614d93bd8bea5227df55e0e3e6

Confirmed that this fixes the broken buildbots:./python -m test test_tools -vvvv -uall -m test_files== CPython 3.8.0a4+ (heads/master:91f4380ced, May 26 2019, 17:30:21) [GCC 8.3.0]== Linux-5.0.15-1-MANJARO-x86_64-with-glibc2.29 little-endian== cwd: /home/pablogsal/github/cpython/build/test_python_25649== CPU count: 12== encodings: locale=UTF-8, FS=utf-8Run tests sequentially0:00:00 load avg: 0.50 [1/1] test_toolstest_files (test.test_tools.test_unparse.DirectoryTestCase) ... Testing /home/pablogsal/github/cpython/Lib/typing.pyTesting /home/pablogsal/github/cpython/Lib/test/test_typing.pyokRan 1 test in 0.586sOK== Tests result: SUCCESS ==1 test OK.Total duration: 671 msTests result: SUCCESSThe manual check is needed because the CI in GitHub does not run test_tools over all files so it does not take forever.