Re: [COMMITTERS] pgsql: Clean up Perl code according to perlcritic

Tom Lane <tgl@sss.pgh.pa.us> writes:

> I wrote:
>> Peter Eisentraut <peter_e@gmx.net> writes:
>>> Clean up Perl code according to perlcritic
>
>> This seems to have broken the regression tests (specifically, dblink)
>> on at least some of the Windows buildfarm critters.
>
> I'm hardly a Perl expert, but it looks to me like the culprit is this
> hunk in vcregress.pl:
>
> @@ -521,8 +521,9 @@ sub fetchRegressOpts
>          # an unhandled variable reference.  Ignore anything that isn't an
>          # option starting with "--".
>          @opts = grep {
> -            s/\Q$(top_builddir)\E/\"$topdir\"/;
> -            $_ !~ /\$\(/ && $_ =~ /^--/
> +            my $x = $_;
> +            $x =~ s/\Q$(top_builddir)\E/\"$topdir\"/;
> +            $x !~ /\$\(/ && $x =~ /^--/
>          } split(/\s+/, $1);
>      }
>      if ($m =~ /^\s*ENCODING\s*=\s*(\S+)/m)
>
> The first line in that block is actually intending to modify the value
> it's inspecting, and perlcritic's "improved" version carefully removes
> the side-effect.
>
> No doubt there are cleaner ways to do that (the comments in "man perlfunc"
> about this coding technique are not positive), but this way is not
> cleaner, it is broken.

I suggest splitting the substitution and filtering part into separate
map and grep calls, for clarity.  The substituion is crying out for the
/r regex modifier to avoid the local variable, but that's only available
since perl 5.14.

diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index d9367f8..cf93a60 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -520,11 +520,9 @@ sub fetchRegressOpts        # Substitute known Makefile variables, then ignore options that retain
      # an unhandled variable reference.  Ignore anything that isn't an        # option starting with "--".
 
-        @opts = grep {
-            my $x = $_;
-            $x =~ s/\Q$(top_builddir)\E/\"$topdir\"/;
-            $x !~ /\$\(/ && $x =~ /^--/
-        } split(/\s+/, $1);
+        @opts = grep { !/\$\(/ && /^--/ }
+            map { (my $x = $_) =~ s/\Q$(top_builddir)\E/\"$topdir\"/; $x;}
+            split(/\s+/, $1);    }    if ($m =~ /^\s*ENCODING\s*=\s*(\S+)/m)    {


-  ilmari

-- 
"The surreality of the universe tends towards a maximum" -- Skud's Law
"Never formulate a law or axiom that you're not prepared to live withthe consequences of."
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