Re: [PATCH v2 2/4] scripts/kernel-doc: Replacing highlights hash by an array

[Mauro Carvalho Chehab <mchehab@osg.samsung.com>]

Em Tue, 17 Nov 2015 07:44:31 -0700
Jonathan Corbet <corbet@lwn.net> escreveu:

> On Tue, 17 Nov 2015 08:40:46 -0200
> Mauro Carvalho Chehab <mchehab@osg.samsung.com> wrote:
> 
> > The above causes some versions of perl to fail, as keys expect a
> > hash argument:
> > 
> > Execution of .//scripts/kernel-doc aborted due to compilation errors.
> > Type of arg 1 to keys must be hash (not private array) at .//scripts/kernel-doc line 2714, near "@highlights) "
> > 
> > This is happening at linuxtv.org server, with runs perl version 5.10.1.
> 
> OK, that's not good.  But I'm not quite sure what to do about it.
> 
> Perl 5.10.1 is a little over six years old.  Nobody else has complained
> (yet) about this problem.  So it might be best to "fix" this with a
> minimum version added to the Changes file.
> 
> Or maybe we need to revert the patch.
> 
> So I'm far from a Perl expert, so I have no clue what the minimum version
> would be if we were to say "5.10.1 is too old."  I don't suppose anybody
> out there knows?

I'm also not a Perl expert, and never saw before the usage of "keys" on
an array. Yet, according with:
	http://perldoc.perl.org/functions/keys.html

"in Perl 5.12 or later only, the indices of an array"

If so, then maybe we could replace:
	foreach my $k (keys @highlights)

by a more C style variant, with all versions of perl 5:
	for (my $k = 0; $k < @highlights; $k++) {

The enclosed patch should do the trick. I tested it with perl 5.10 and 
perl 5.22 it worked fine with both versions.

Regards,
Mauro

-

kernel-doc: Make it compatible with Perl versions below 5.12 again

Changeset 4d73270192ec('scripts/kernel-doc: Replacing highlights
hash by an array') broke compatibility of the kernel-doc script with
older versions of perl by using "keys ARRAY" syntax with is available
only on Perl 5.12 or newer, according with:
	http://perldoc.perl.org/functions/keys.html

Restore backward compatibility by replacing "foreach my $k (keys ARRAY)"
by a C-like variant: "for (my $k = 0; $k < !ARRAY; $k++)"

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 125b906..1f61def 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -2711,7 +2711,7 @@ $kernelversion = get_kernel_version();
 
 # generate a sequence of code that will splice in highlighting information
 # using the s// operator.
-foreach my $k (keys @highlights) {
+for (my $k = 0; $k < @highlights; $k++) {
     my $pattern = $highlights[$k][0];
     my $result = $highlights[$k][1];
 #   print STDERR "scanning pattern:$pattern, highlight:($result)\n";