[Python-Dev] Issue #26204: compiler now emits a SyntaxWarning on constant statement

[Chris Barker]

On Mon, Feb 8, 2016 at 1:51 PM, Victor Stinner <victor.stinner at gmail.com>
wrote:

> I didn't know. I just checked. It's assert used with a non-empty tuple:
>
> >>> assert ("tuple",)
>

which is more interesting with a tuple without the parentheses:

t = In [*4*]: t = True,

In [*5*]: t

Out[*5*]: (True,)

works fine, but not if you use an assert:

In [*7*]: assert True,

  File "<ipython-input-7-38940c80755c>", line 1

    assert True,

                ^

SyntaxError: invalid syntax
I actually like the Warning with the note about the problem better:

<stdin>:1: SyntaxWarning: assertion is always true, perhaps remove
> parentheses?


And, of course, more relevant with something Falsey in the tuple:

In [*14*]: assert (False,)

<ipython-input-14-05f425f558c4>:1: SyntaxWarning: assertion is always true,
perhaps remove parentheses?

  assert (False,)

But I am curious why you get a different error without the parens?

-CHB


-- 

Christopher Barker, Ph.D.
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