Funny behavior of IDLE 3.7.0
Terry Reedy
tjreedy at udel.edu
Tue Nov 12 18:58:58 EST 2019
On 11/12/2019 12:00 PM, Chris Angelico wrote:
> On Wed, Nov 13, 2019 at 3:57 AM Terry Reedy <tjreedy at udel.edu> wrote:
>>
>> On 11/12/2019 8:29 AM, Chris Angelico wrote:
>>
>>> The OP said that the equals sign in the *first* line was flagged as
>>> invalid syntax. Implication being that the error is being reported on
>>> the line "i = 4", not on the print at the end. And in fact, I can
>>> confirm this. Run | Check Module reports an error where i is assigned
>>> to. Here's how it looks in command-line Python:
>>>
>>> $ python3.7 demo.py
>>> File "<fstring>", line 1
>>> (i=)
>>> ^
>>> SyntaxError: invalid syntax
>>>
>>> Newer Pythons are happy with this example, but if you replace the
>>> error with something else - say, f'{i+}' - then the same phenomenon
>>> occurs. Command-line Python reports the error on line 1 of
>>> "<fstring>", and Idle misinterprets that as line 1 of the original
>>> file.
>>>
>>> This looks like an error reporting flaw in f-string handling.
>>
>> Can you open a bug issue (if not one already) and nosy me?
>> This is awful for any IDE that processes error messages.
>>
>> Replacing {} with () is a secondary bug. The actual code
>> {i=}
>> would be clearer, and make it easier for an IDE to search for the real line.
>>
>
> I can do that, but I actually think the correct fix isn't inside Idle.
Right. I meant a bug report against core Python.
If the real bug is not fixed, I might do a workaround for IDLE, but I
would prefer not.
> See the followup regarding the difference between SyntaxError and
> NameError; in the latter case, the error is more usefully reported.
>
> ChrisA
>
--
Terry Jan Reedy
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