Activate perlcritic InputOutput::RequireCheckedSyscalls and fix resulting warnings

This checks that certain I/O-related Perl functions properly check
their return value.  Some parts of the PostgreSQL code had been a bit
sloppy about that.  The new perlcritic warnings are fixed here.  I
didn't design any beautiful error messages, mostly just used "or die
$!", which mostly matches existing code, and also this is
developer-level code, so having the system error plus source code
reference should be ok.

Initially, we only activate this check for a subset of what the
perlcritic check would warn about.  The effective list is

    chmod flock open read rename seek symlink system

The initial set of functions is picked because most existing code
already checked the return value of those, so any omissions are
probably unintended, or because it seems important for test
correctness.

The actual perlcritic configuration is written as an exclude list.
That seems better so that we are clear on what we are currently not
checking.  Maybe future patches want to investigate checking some of
the other functions.  (In principle, we might eventually want to check
all of them, but since this is test and build support code, not
production code, there are probably some reasonable compromises to be
made.)

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/flat/88b7d4f2-46d9-4cc7-b1f7-613c90f9a76a%40eisentraut.org

2 files changed, 14 insertions, 14 deletions

diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index 4ea10d063c4..b08296605c4 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -467,7 +467,7 @@ sub set_replication_conf
 	$self->host eq $test_pghost
 	  or croak "set_replication_conf only works with the default host";
 
-	open my $hba, '>>', "$pgdata/pg_hba.conf";
+	open my $hba, '>>', "$pgdata/pg_hba.conf" or die $!;
 	print $hba
 	  "\n# Allow replication (set up by PostgreSQL::Test::Cluster.pm)\n";
 	if ($PostgreSQL::Test::Utils::windows_os
@@ -580,7 +580,7 @@ sub init
 	PostgreSQL::Test::Utils::system_or_bail($ENV{PG_REGRESS},
 		'--config-auth', $pgdata, @{ $params{auth_extra} });
 
-	open my $conf, '>>', "$pgdata/postgresql.conf";
+	open my $conf, '>>', "$pgdata/postgresql.conf" or die $!;
 	print $conf "\n# Added by PostgreSQL::Test::Cluster.pm\n";
 	print $conf "fsync = off\n";
 	print $conf "restart_after_crash = off\n";
@@ -862,7 +862,7 @@ sub init_from_backup
 		rmdir($data_path);
 		PostgreSQL::Test::RecursiveCopy::copypath($backup_path, $data_path);
 	}
-	chmod(0700, $data_path);
+	chmod(0700, $data_path) or die $!;
 
 	# Base configuration for this node
 	$self->append_conf(
@@ -1688,16 +1688,16 @@ sub _reserve_port
 		if (kill 0, $pid)
 		{
 			# process exists and is owned by us, so we can't reserve this port
-			flock($portfile, LOCK_UN);
+			flock($portfile, LOCK_UN) || die $!;
 			close($portfile);
 			return 0;
 		}
 	}
 	# All good, go ahead and reserve the port
-	seek($portfile, 0, SEEK_SET);
+	seek($portfile, 0, SEEK_SET) || die $!;
 	# print the pid with a fixed width so we don't leave any trailing junk
 	print $portfile sprintf("%10d\n", $$);
-	flock($portfile, LOCK_UN);
+	flock($portfile, LOCK_UN) || die $!;
 	close($portfile);
 	push(@port_reservation_files, $filename);
 	return 1;
diff --git a/src/test/perl/PostgreSQL/Test/Utils.pm b/src/test/perl/PostgreSQL/Test/Utils.pm
index 2185a079def..42d5a50dc88 100644
--- a/src/test/perl/PostgreSQL/Test/Utils.pm
+++ b/src/test/perl/PostgreSQL/Test/Utils.pm
@@ -211,10 +211,10 @@ INIT
 	  or die "could not open STDOUT to logfile \"$test_logfile\": $!";
 
 	# Hijack STDOUT and STDERR to the log file
-	open(my $orig_stdout, '>&', \*STDOUT);
-	open(my $orig_stderr, '>&', \*STDERR);
-	open(STDOUT, '>&', $testlog);
-	open(STDERR, '>&', $testlog);
+	open(my $orig_stdout, '>&', \*STDOUT) or die $!;
+	open(my $orig_stderr, '>&', \*STDERR) or die $!;
+	open(STDOUT, '>&', $testlog) or die $!;
+	open(STDERR, '>&', $testlog) or die $!;
 
 	# The test output (ok ...) needs to be printed to the original STDOUT so
 	# that the 'prove' program can parse it, and display it to the user in
@@ -564,7 +564,7 @@ Find and replace string of a given file.
 sub string_replace_file
 {
 	my ($filename, $find, $replace) = @_;
-	open(my $in, '<', $filename);
+	open(my $in, '<', $filename) or croak $!;
 	my $content = '';
 	while (<$in>)
 	{
@@ -572,7 +572,7 @@ sub string_replace_file
 		$content = $content . $_;
 	}
 	close $in;
-	open(my $out, '>', $filename);
+	open(my $out, '>', $filename) or croak $!;
 	print $out $content;
 	close($out);
 
@@ -789,11 +789,11 @@ sub dir_symlink
 			# need some indirection on msys
 			$cmd = qq{echo '$cmd' | \$COMSPEC /Q};
 		}
-		system($cmd);
+		system($cmd) == 0 or die;
 	}
 	else
 	{
-		symlink $oldname, $newname;
+		symlink $oldname, $newname or die $!;
 	}
 	die "No $newname" unless -e $newname;
 }