run script to check that .po files don't have empty strings

.travis.yml

@@ -31,6 +31,7 @@ install:
   - sed -i -e 's|\$server_domain = "openfoodfacts.org";|\$server_domain = "off.travis-ci.org";|g' $TRAVIS_BUILD_DIR/lib/ProductOpener/Config2.pm
   - sed -i -e 's|\/home\/off|'$TRAVIS_BUILD_DIR'|g' $TRAVIS_BUILD_DIR/lib/ProductOpener/Config2.pm
 script:
+  - scripts/check_po_file.pl $TRAVIS_BUILD_DIR/po/tags/en.po
   - prove -l
   - perl -c -CS -I$TRAVIS_BUILD_DIR/lib lib/startup_apache2.pl
   - perl -c -CS -I$TRAVIS_BUILD_DIR/lib cgi/product_multilingual.pl

scripts/check_po_file.pl

@@ -0,0 +1,55 @@
+#!/usr/bin/perl
+
+use strict;
+use utf8;
+use warnings;
+
+my $file = $ARGV[0];
+
+if (not defined $file) {
+	print STDERR "Pass path to .po file to test as first argument.\n";
+	exit(1);
+}
+
+print STDERR "Testing $file .po file";
+
+
+open (my $IN, "<:encoding(UTF-8)", "$file") or die("Could not read $file: $!");
+my @lines = (<$IN>);
+close ($IN);
+
+my %vars = ();
+my $key;
+
+my $errors = 0;
+
+foreach my $line (@lines) {
+
+	if ($line =~ /^(msgctxt|msgstr|msgid) "(.*)"/) {
+		$key = $1;
+		my $value = $2;
+		if ($key eq "msgctxt") {
+
+			if (defined $vars{"msgctxt"}) {
+
+				# check that we do not have an empty value for the previous msgctxt
+
+				if ((not defined $vars{"msgstr"}) or ($vars{"msgstr"} eq "")) {
+					print STDERR "Error: empty msgstr string for msgctxt " . $vars{"msgctxt"} . " - msgid " . $vars{"msgid"} . "\n";
+					$errors++;
+				}
+
+			}
+
+			%vars = ();
+
+
+		}
+		defined $vars{$key} or $vars{$key} = "";
+		$vars{$key} .= $value;
+	}
+
+}
+
+print STDERR "$errors errors\n";
+exit($errors);