On Mon, Jun 6, 2011 at 23:57, Georg Brandl
<g.brandl@gmx.net> wrote:
On 06/07/11 05:20, brett.cannon wrote:
>
http://hg.python.org/cpython/rev/fc282e375703
> changeset: 70695:fc282e375703
> user: Brett Cannon <
brett@python.org>
> date: Mon Jun 06 20:20:36 2011 -0700
> summary:
> Remove some extraneous parentheses and swap the comparison order to
> prevent accidental assignment.
>
> Silences a warning from LLVM/clang 2.9.
lots of others around (e.g. "len == 0" in the patch context below). Why is
this one so special?
Old habit on how to do comparisons in C. Because C treats assignment as an expression it means comparisons can accidentally become an assignment if you accidentally leave out an = sign. By reversing this order it is simply not possible to have that silent bug and instead you would get a compiler error about trying to assign to a constant.
I'll revert that part of the change.
I think that another developer even got told off once for these kinds of
comparisons.
I hope the Clang warning is only about the parentheses.
Yes, Clang only warned about the parentheses.
-Brett
Georg
> files:
> Modules/arraymodule.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
>
> diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
> --- a/Modules/arraymodule.c
> +++ b/Modules/arraymodule.c
> @@ -2091,7 +2091,7 @@
> if (len == 0) {
> return PyUnicode_FromFormat("array('%c')", (int)typecode);
> }
> - if ((typecode == 'u'))
> + if ('u' == typecode)
> v = array_tounicode(a, NULL);
> else
> v = array_tolist(a, NULL);
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