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Support for 3.6 f-string syntax

See original GitHub issue

Apologies for the brief report, but here’s a simple bug reproduction session in the shell:

$ mktmpenv -p python3.6  # this command is from virtualenvwrapper
(tmp-38ce2dcf0268df9) $ python --version
Python 3.6.0b2
(tmp-38ce2dcf0268df9) $ cat test.py 
target = "world"
print(f"Hello, {target}!")
(tmp-38ce2dcf0268df9) $ python test.py 
Hello, world!
(tmp-38ce2dcf0268df9) $ pip install yapf==0.14.0
(tmp-38ce2dcf0268df9) $ yapf -i test.py
Traceback (most recent call last):
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/yapflib/pytree_utils.py", line 102, in ParseCodeToTree
    tree = parser_driver.parse_string(code, debug=False)
  File "/home/dpassaro/.pyenv/versions/3.6.0b2/lib/python3.6/lib2to3/pgen2/driver.py", line 106, in parse_string
    return self.parse_tokens(tokens, debug)
  File "/home/dpassaro/.pyenv/versions/3.6.0b2/lib/python3.6/lib2to3/pgen2/driver.py", line 71, in parse_tokens
    if p.addtoken(type, value, (prefix, start)):
  File "/home/dpassaro/.pyenv/versions/3.6.0b2/lib/python3.6/lib2to3/pgen2/parse.py", line 159, in addtoken
    raise ParseError("bad input", type, value, context)
lib2to3.pgen2.parse.ParseError: bad input: type=3, value='"Hello, {target}!"', context=('', (2, 7))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/bin/yapf", line 11, in <module>
    sys.exit(run_main())
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/__init__.py", line 296, in run_main
    sys.exit(main(sys.argv))
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/__init__.py", line 188, in main
    parallel=args.parallel)
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/__init__.py", line 236, in FormatFiles
    in_place, print_diff, verify)
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/__init__.py", line 259, in _FormatFile
    logger=logging.warning)
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/yapflib/yapf_api.py", line 90, in FormatFile
    verify=verify)
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/yapflib/yapf_api.py", line 126, in FormatCode
    tree = pytree_utils.ParseCodeToTree(unformatted_source)
  File "/home/dpassaro/.virtualenvs/tmp-38ce2dcf0268df9/lib/python3.6/site-packages/yapf/yapflib/pytree_utils.py", line 108, in ParseCodeToTree
    tree = parser_driver.parse_string(code, debug=False)
  File "/home/dpassaro/.pyenv/versions/3.6.0b2/lib/python3.6/lib2to3/pgen2/driver.py", line 106, in parse_string
    return self.parse_tokens(tokens, debug)
  File "/home/dpassaro/.pyenv/versions/3.6.0b2/lib/python3.6/lib2to3/pgen2/driver.py", line 71, in parse_tokens
    if p.addtoken(type, value, (prefix, start)):
  File "/home/dpassaro/.pyenv/versions/3.6.0b2/lib/python3.6/lib2to3/pgen2/parse.py", line 159, in addtoken
    raise ParseError("bad input", type, value, context)
lib2to3.pgen2.parse.ParseError: bad input: type=3, value='"Hello, {target}!"', context=('', (2, 7))

Issue Analytics

State:
Created 7 years ago
Reactions:35
Comments:31 (8 by maintainers)

Top GitHub Comments

11reactions

bolinfestcommented, Apr 14, 2017

Can we accept the really hacky fix then? Once you start using f-strings, there’s no going back to %s.

9reactions

bwendlingcommented, Apr 18, 2017

Notice that this is something they plan on fixing in lib2to3

https://bugs.python.org/issue23894

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