Re: [Qemu-devel] [PATCH] readline: avoid memcpy() of overlapping regions

[Blue Swirl]

On Thu, Jan 10, 2013 at 12:43 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Wed, Jan 09, 2013 at 08:43:51PM +0000, Blue Swirl wrote:
>> On Tue, Jan 8, 2013 at 9:03 AM, Stefan Hajnoczi <address@hidden> wrote:
>> > On Mon, Jan 07, 2013 at 03:38:39PM -0500, Nickolai Zeldovich wrote:
>> >> memcpy() for overlapping regions is undefined behavior; use memmove()
>> >> instead in readline_hist_add().
>> >>
>> >> Signed-off-by: Nickolai Zeldovich <address@hidden>
>> >> ---
>> >>  readline.c |    4 ++--
>> >>  1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > I made a slight modification: keep the tab characters since the
>> > surrounding code still uses them.
>>
>> I think tabs should be fixed whenever possible, otherwise we may never
>> get them converted.
>
> Not in a one-line patch when the surrounding lines still use them.  It
> creates a mess.

Only if the reader messes with the tab width settings (and in that
case they deserve what they get and they are probably also used to
this), otherwise a line with tabs converted to spaces looks exactly
the same.

I think this is identical case to braces. If we don't allow mass
conversion, conversion as a side effect is the only way and then it
should be always followed.

>
> Stefan