Re: [PATCH] Use raw strings on gdb.python/py-xmethods.exp (and fix Python 3.8's "SyntaxWarning: invalid escape sequence")

[Sergio Durigan Junior <sergiodj at redhat dot com>]

On Sunday, August 25 2019, Simon Marchi wrote:

> On 2019-08-25 12:21 p.m., Sergio Durigan Junior wrote:
>> The way unrecognized escape sequences are handled has changed in
>> Python 3.8: users now see a SyntaxWarning message, which will
>> eventually become a SyntaxError in future versions of Python:
>> 
>>   (gdb) source /blabla/gdb.python/py-xmethods/py-xmethods.py
>>   /blabla/gdb.python/py-xmethods/py-xmethods.py:204: SyntaxWarning: invalid escape seque
>>   nce \+
>>     'operator\+',
>>   /blabla/gdb.python/py-xmethods/py-xmethods.py:211: SyntaxWarning: invalid escape seque
>>   nce \+
>>     'operator\+\+',
>> 
>> One of our testcases, gdb.python/py-xmethods.exp, contains strings in
>> the form of "operator\+".  This is not recognized by Python, but is
>> still needed by the testsuite to work properly.  The solution is
>> simple: we just have to make sure these strings are marked as
>> raw (i.e, r"").  This is what this patch does.  I took the opportunity
>> to also convert other strings to raw, which, in two cases, allowed the
>> removal of an extra backslash.
>> 
>> I tested this using Python 3.7 and Python 3.8, and everything works
>> fine.
>> 
>> I think I could push this as obvious, but decided to send it to
>> gdb-patches just in case.
>
> Just to understand correctly, could you have also changed
>
>   'operator\+'
>
> to
>
>   'operator\\+'
>
> ?

Yeah, that works as well.  I thought it made more sense to use raw
strings because that's what the documentation seems to recommend, and
also what other projects started using.

> In any case, I think using raw strings is a good solution, it requires less escaping, so your patch LGTM.

Thanks, pushed: d9c4ba536c522b8dc2194d4100270a159be7894a

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Sergio
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