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

[Simon Marchi <simark at simark dot ca>]

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\\+'

?

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

Simon