Use perl warnings pragma consistently

We've had a mixture of the warnings pragma, the -w switch on the shebang
line, and no warnings at all. This patch removes the -w swicth and add
the warnings pragma to all perl sources missing it. It raises the
severity of the TestingAndDebugging::RequireUseWarnings  perlcritic
policy to level 5, so that we catch any future violations.

Discussion: https://postgr.es/m/20200412074245.GB623763@rfd.leadboat.com

8 files changed, 15 insertions, 3 deletions

diff --git a/src/tools/fix-old-flex-code.pl b/src/tools/fix-old-flex-code.pl
index 2954cf5a726..1bbb7cdb841 100644
--- a/src/tools/fix-old-flex-code.pl
+++ b/src/tools/fix-old-flex-code.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 #----------------------------------------------------------------------
 #
 # fix-old-flex-code.pl
diff --git a/src/tools/msvc/build.pl b/src/tools/msvc/build.pl
index 2e47f24783f..3c886fcd499 100644
--- a/src/tools/msvc/build.pl
+++ b/src/tools/msvc/build.pl
@@ -3,6 +3,7 @@
 # src/tools/msvc/build.pl
 
 use strict;
+use warnings;
 
 use File::Basename;
 use File::Spec;
diff --git a/src/tools/msvc/pgbison.pl b/src/tools/msvc/pgbison.pl
index 490df833673..774d5be0595 100644
--- a/src/tools/msvc/pgbison.pl
+++ b/src/tools/msvc/pgbison.pl
@@ -3,6 +3,8 @@
 # src/tools/msvc/pgbison.pl
 
 use strict;
+use warnings;
+
 use File::Basename;
 
 # assume we are in the postgres source root
diff --git a/src/tools/msvc/pgflex.pl b/src/tools/msvc/pgflex.pl
index aceed5ffd6c..26c73dbfade 100644
--- a/src/tools/msvc/pgflex.pl
+++ b/src/tools/msvc/pgflex.pl
@@ -3,6 +3,8 @@
 # src/tools/msvc/pgflex.pl
 
 use strict;
+use warnings;
+
 use File::Basename;
 
 # silence flex bleatings about file path style
diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index 82dca29a616..c39178a93ca 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -3,6 +3,7 @@
 # src/tools/msvc/vcregress.pl
 
 use strict;
+use warnings;
 
 our $config;
 
diff --git a/src/tools/perlcheck/perlcriticrc b/src/tools/perlcheck/perlcriticrc
index bd848a9a653..314c83c6a59 100644
--- a/src/tools/perlcheck/perlcriticrc
+++ b/src/tools/perlcheck/perlcriticrc
@@ -19,6 +19,10 @@ verbose = %f: %m at line %l, column %c.  %e.  ([%p] Severity: %s)\n
 # allow octal constants with leading zeros
 [-ValuesAndExpressions::ProhibitLeadingZeros]
 
+# insist on use of the warnings pragma
+[TestingAndDebugging::RequireUseWarnings]
+severity = 5
+
 # for now raise severity of this to level 5
 [Subroutines::RequireFinalReturn]
 severity = 5
diff --git a/src/tools/pginclude/pgcheckdefines b/src/tools/pginclude/pgcheckdefines
index 4edf7fc56e8..0a760d6ecad 100755
--- a/src/tools/pginclude/pgcheckdefines
+++ b/src/tools/pginclude/pgcheckdefines
@@ -1,4 +1,4 @@
-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #
 # This script looks for symbols that are referenced in #ifdef or defined()
@@ -21,6 +21,7 @@
 #
 
 use strict;
+use warnings;
 
 use Cwd;
 use File::Basename;
diff --git a/src/tools/version_stamp.pl b/src/tools/version_stamp.pl
index cb59ad234ab..fcd3f180487 100755
--- a/src/tools/version_stamp.pl
+++ b/src/tools/version_stamp.pl
@@ -1,4 +1,4 @@
-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #################################################################
 # version_stamp.pl -- update version stamps throughout the source tree
@@ -21,6 +21,7 @@
 #
 
 use strict;
+use warnings;
 
 # Major version is hard-wired into the script.  We update it when we branch
 # a new development version.