Author terry.reedy
Recipients David Bieber, benjamin.peterson, brett.cannon, ncoghlan, terry.reedy, yselivanov
Date 2017-10-13.22:03:43
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It has been some time since literal_eval literally only evaluated literals.  'constant_eval' might be a better name now, with the proviso of 'safely, in reasonable time'.

>>> from ast import literal_eval as le
>>> le('(1,2,3)')
(1, 2, 3)
>>> le('(1,2, (3,4))')
(1, 2, (3, 4))

I believe there was once a time when a simple tuple would be evaluated, while a nested one would not be.

"It is not capable of evaluating arbitrarily complex expressions, for example involving operators or indexing."  I do not read this as prohibiting all operators, but rather that now all will be accepted.

>>> le(2**2)
ValueError: malformed node or string: 4

Exponentiation of ints can take exponential time and can be used for denial of service attacks.

>>> le('2017-10-10')

This is correct.  For '2017-10-10' to be a string representing a date, it must be quoted as a string in the code.

>>> le("'2017-10-10'")

Rolling back previous enhancements would break existing code, so a deprecation period would be required.  But I would be inclined to instead update the doc to match the updated code better.  Lets see what others think.
Date User Action Args
2017-10-13 22:03:44terry.reedysetrecipients: + terry.reedy, brett.cannon, ncoghlan, benjamin.peterson, yselivanov, David Bieber
2017-10-13 22:03:44terry.reedysetmessageid: <>
2017-10-13 22:03:44terry.reedylinkissue31778 messages
2017-10-13 22:03:43terry.reedycreate