[PATCH v2] devtools: allow variable declaration inside for loop

[Tyler Retzlaff]

On Wed, May 03, 2023 at 05:01:01PM +0200, Thomas Monjalon wrote:
> 03/05/2023 14:19, Morten Brørup:
> > > From: Bruce Richardson [mailto:bruce.richardson at intel.com]
> > > Sent: Wednesday, 3 May 2023 12.57
> > > 
> > > On Wed, May 03, 2023 at 11:30:53AM +0100, Ferruh Yigit wrote:
> > > > Declaring variable inside for loop is not supported via C89 and it was
> > > > checked in checkpatch.sh via commit [1].
> > > > But as DPDK supported C standard is becoming C99/C11 [2], declaring
> > > > variable inside loop can be allowed.
> > > >
> > > > [1]
> > > > Commit 43e73483a4b8 ("devtools: forbid variable declaration inside
> > > for")
> > > >
> > > > [2]
> > > > https://dpdk.org/patch/121912
> > > >
> > > > Signed-off-by: Ferruh Yigit <ferruh.yigit at amd.com>
> > > > ---
> > > > Cc: Bruce Richardson <bruce.richardson at intel.com>
> > > > Cc: David Marchand <david.marchand at redhat.com>
> > > >
> > > > v2:
> > > >  * Update coding convention too
> > > > ---
> > > 
> > > Acked-by: Bruce Richardson <bruce.richardson at intel.com>
> > 
> > Acked-by: Morten Brørup <mb at smartsharesystems.com>
> > 
> > [...]
> > 
> > > > @@ -558,6 +558,7 @@ Local Variables
> > > >
> > > >  * Variables should be declared at the start of a block of code rather
> > > than in the middle.
> > > 
> > > I'd love to see this restriction removed in future too. Having a
> > > variable
> > > declared on first use in the middle of block I find a far easier way of
> > > working as a) it saves scrolling to look for variable definitions and b)
> > > it
> > > makes it far easier when adding/removing blocks of code e.g. commenting
> > > out
> > > for testing,  to have all the code together rather than having variables
> > > at
> > > the top to add/remove also.
> > 
> > And c) Initializing the variables close to where they are used the first time reduces the risk of initializing them incorrectly. Especially when modifying a block of code, initialization of its variables might be missed if out of sight. (Although this is probably a consequence of "a)".)
> > 
> > I consider it old style to only declare variables at the start of a block of code, and this style of coding should be considered obsolete.
> > 
> > If you are really old (like me?), you might remember when function parameters were provided like this:
> > 
> > int main(argc, argv)
> > int argc;
> > char *argv[];
> > {
> > 	return(0);
> > }

heh, k&r C

> > 
> > We have moved on from that to a more modern coding style a long time ago. We should also move on to a more modern coding style regarding variable declarations.
> 
> Old men are used to look for variable types at the beginning of functions.
> Having only new code adopting a different style may be confusing a little.
> Note I'm not against it, just asking for more feedbacks.

Acked-by: Tyler Retzlaff <roretzla at linux.microsoft.com>

+1 for declare in minimum necessary scope
+1 for declare at first use (enables more use of const)

thank you!