DatesRole: be more resilient in the face of adversity.

- Settle on `undef` as a signal for failure.
- Maintain regex in a `state` variable.
- Return undef if it doesn't match our regex.
- Don't die if its still unparseable.

Also, add Test::Most and Try::Tiny to `dist.ini` just to give
@jagtalon something to do this week. :D

dist.ini

@@ -24,8 +24,10 @@ Text::Unidecode = 0.04
 Date::Calc = 6.3
 Date::Hijri = 0.02
 Date::Leapyear = 1.72
+# Dates role, et. al.
 DateTime = 0.74
 DateTime::Format::HTTP = 0
+Try::Tiny = 0
 Lingua::EN::Numericalize = 1.52
 Lingua::PigLatin = 0.01
 Locale::SubCountry = 1.47
@@ -75,6 +77,7 @@ Bit::Vector = 7.3
 
 [Prereqs / TestRequires]
 Test::More = 0.98
+Test::Most = 0
 Test::Dirs = 0.03
 File::Temp = 0.22
 

lib/DDG/GoodieRole/Dates.pm

@@ -2,9 +2,11 @@ package DDG::GoodieRole::Dates;
 
 use strict;
 use warnings;
+use feature 'state';
 
 use Moo::Role;
 use DateTime;
+use Try::Tiny;
 
 # This appears to parse most/all of the big ones, however it doesn't present a regex
 use DateTime::Format::HTTP;
@@ -59,22 +61,23 @@ sub date_regex {
     ## Ambiguous, but potentially valid date formats
     push @regexes, $ambiguous_dates;
 
-    my $returned_regex = join '|', @regexes;
+    state $returned_regex = join '|', @regexes;
     return qr/$returned_regex/i;
 }
 
 sub parse_string_to_date {
     my ($d) = @_;
 
-    # guesswork for ambigous DMY/MDY and switch to ISO
+    return unless ($d =~ date_regex());    # Only handle white-listed strings, even if they might otherwise work.
     if ($d =~ $ambiguous_dates) {
-        my $month = $1;    # Assume MDY, even though it's crazy, for backward compatibility
+        # guesswork for ambigous DMY/MDY and switch to ISO
+        my $month = $1;                    # Assume MDY, even though it's crazy, for backward compatibility
         my $day   = $2;
         my $year  = $3;
 
         if ($month > 12) {
             # Months over 12 don't make any sense, so must not be MDY
-            return if ($day > 12);    # what we took as day must not be month, either.  No idea how to proceed.
+            return if ($day > 12);         # what we took as day must not be month, either.  No idea how to proceed.
             ($day, $month) = ($month, $day);    # month and day must be swapped, then.
         }
 
@@ -84,7 +87,10 @@ sub parse_string_to_date {
     $d =~ s/(\d+)\s?$number_suffixes/$1/i;                                       # Strip ordinal text.
     $d =~ s/($full_month)/$full_month_to_short{lc $1}/i;                         # Parser deals better with the shorter month names.
     $d =~ s/^($short_month)$date_delim(\d{1,2})/$2-$short_month_fix{lc $1}/i;    #Switching Jun-01-2012 to 01 Jun 2012
-    return DateTime::Format::HTTP->parse_datetime($d);
+
+    my $maybe_date_object = try { DateTime::Format::HTTP->parse_datetime($d) };  # Don't die no matter how bad we did with checking our string.
+
+    return $maybe_date_object;
 }
 
 1;

t/00-roles.t

@@ -2,7 +2,7 @@
 
 use strict;
 use warnings;
-use Test::More;
+use Test::Most;
 
 subtest 'NumberStyler' => sub {
 
@@ -112,6 +112,9 @@ subtest 'Dates' => sub {
     
     foreach my $test_string (@strings_to_ignore) {
         unlike($test_string, qr/^$test_regex$/, "$test_string doesn't match");
+        my $result;
+        lives_ok { $result = RoleTester::parse_string_to_date($test_string) } '... nor does it kill the parser.';
+        is($result, undef, '... and returns undef to signal failure.');
     }
 
 };