Terry J. Reedy <[email protected]> added the comment:
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')
1997
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'")
'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.
----------
nosy: +benjamin.peterson, brett.cannon, ncoghlan, terry.reedy, yselivanov
type: behavior -> enhancement
versions: -Python 3.4, Python 3.5, Python 3.6
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<https://bugs.python.org/issue31778>
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