In Parser\parser.c in classify, the 'str' parameter is assigned into the local variable 's'. However, 'str' is not used anywhere else in the function, which makes 's' redundant.

My proposal is to simply remove 's', and just use 'str' instead.

The diff is attached.

I played a little with the interpreter, and everything worked as usual.
In addition, I run 'python -m test' (on my 64-bit Windows 10) before and after applying the patch, and got the same output:
354 tests OK.
1 test altered the execution environment:
    test_subprocess
45 tests skipped:
    test_bz2 test_crypt test_curses test_dbm_gnu test_dbm_ndbm
    test_devpoll test_epoll test_fcntl test_fork1 test_gdb test_grp
    test_idle test_ioctl test_kqueue test_lzma test_nis test_openpty
    test_ossaudiodev test_pipes test_poll test_posix test_pty test_pwd
    test_readline test_resource test_smtpnet test_socketserver
    test_spwd test_sqlite test_ssl test_syslog test_tcl
    test_threadsignals test_timeout test_tix test_tk test_ttk_guionly
    test_ttk_textonly test_urllib2net test_urllibnet test_wait3
    test_wait4 test_winsound test_xmlrpc_net test_zipfile64

Looks good to me. s was probably left over after a rewrite of the function.

Yes it looks like this is code left over from removing the “register” keyword in revision 0530aadff696, Issue 18722. I quickly looked over the changes in that revision. I couldn’t find any more clear redundancies.

I guess this patch is also applicable to 3.5.

Maybe the following comments and copies are not needed either. But these cases look like heavily optimized code, so I would be careful with them:

https://hg.python.org/cpython/file/4b1bca0b560f/Objects/stringlib/codecs.h#l40
https://hg.python.org/cpython/file/4b1bca0b560f/Objects/stringlib/codecs.h#l519
https://hg.python.org/cpython/file/4b1bca0b560f/Objects/stringlib/find_max_char.h#l26
https://hg.python.org/cpython/file/4b1bca0b560f/Objects/unicodeobject.c#l4794
https://hg.python.org/cpython/file/4b1bca0b560f/Objects/unicodeobject.c#l4819

The last two have mangled comments /* Help allocation */, which previously read /* Help register allocation */.

Sorry, the revision removing “register” is e7f6cef7a4cc. Not sure what happened there.

New changeset a90f5e2b7160 by Berker Peksag in branch 'default':
Issue #26130: Remove redundant variable 's' from Parser/parser.c
https://hg.python.org/cpython/rev/a90f5e2b7160

Thanks for the patch, Oren!