Re: latest checkpatch

Andy Whitcroft
2007-10-18T19:25:46Z

On Thu, Oct 18, 2007 at 01:13:52PM +0200, Ingo Molnar wrote:
>
> latest checkpatch.pl works really well on sched.c.
>
> there's only one problem left, this bogus false positive warning
> reappeared:
>
> WARNING: braces {} are not necessary for single statement blocks
> #5710: FILE: sched.c:5710:
> + if (parent->groups == parent->groups->next) {
> + pflags &= ~(SD_LOAD_BALANCE |
> + SD_BALANCE_NEWIDLE |
> + SD_BALANCE_FORK |
> + SD_BALANCE_EXEC |
> + SD_SHARE_CPUPOWER |
> + SD_SHARE_PKG_RESOURCES);
> + }
>
> (there's another place in sched.c that trips this up too.)

It actually never went away, some of the wronger reports went away such
as counting a commented statement as a single statement. The check for
length didn't make the cut for 0.11, as I was still thinking about
whether we wanted a subjective check on statements over and above the
"real" check for lines.

> i think it has been pointed out numerous times that it is perfectly fine
> to use curly braces for multi-line single-statement blocks. That
> includes simple cases like this too:
>
> if (x) {
> /* do y() */
> y();
> }

Yes and the comment in there actually counts as a statement for counting
statement purposes.

The plan is to move to counting lines and only winge on exactly one
line. I have half a mind to make a subjective check on statements and a
full check on lines. But probabally it will just move to lines.

> it's perfectly legitimate, in fact more robust. So if checkpatch.pl
> wants to make any noise about such constructs it should warn about the
> _lack_ of curly braces in every multi-line condition block _except_ the
> only safe single-line statement:
>
> if (x)
> y();

Indeed. We should probabally do more on the indentation checks in
general. The current direct check for:

if (foo);
bar();

Could probabally be generalised to look for this kind of error:

if (foo)
bar();
baz();
one();

-apw