Improve IC::DT timezone checker POD, add note explaining code weirdness

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / InflateColumn / DateTime.pm

diff --git a/lib/DBIx/Class/InflateColumn/DateTime.pm b/lib/DBIx/Class/InflateColumn/DateTime.pm
index 17567be..a46da64 100644 (file)
--- a/lib/DBIx/Class/InflateColumn/DateTime.pm
+++ b/lib/DBIx/Class/InflateColumn/DateTime.pm
@@ -88,10 +88,24 @@ sub register_column {
   my ($self, $column, $info, @rest) = @_;
   $self->next::method($column, $info, @rest);
   return unless defined($info->{data_type});
-  my $type = lc($info->{data_type});
-  $type = 'datetime' if ($type =~ /^timestamp/);
-  $type = 'datetime' if $info->{inflate_datetime};
-  $type = 'date' if $info->{inflate_date};
+
+  my $type;
+
+  for (qw/date datetime/) {
+    my $key = "inflate_${_}";
+
+    next unless exists $info->{$key};
+    return unless $info->{$key};
+
+    $type = $_;
+    last;
+  }
+
+  unless ($type) {
+    $type = lc($info->{data_type});
+    $type = 'datetime' if ($type =~ /^timestamp/);
+  }
+
   my $timezone;
   if ( exists $info->{extra} and exists $info->{extra}{timezone} and defined $info->{extra}{timezone} ) {
     $timezone = $info->{extra}{timezone};
@@ -99,12 +113,24 @@ sub register_column {
 
   my $undef_if_invalid = $info->{datetime_undef_if_invalid};
 
-  my $do_inflate = 1;
-  $do_inflate = 0 if exists $info->{inflate_datetime} and $info->{inflate_datetime} == 0;
-  $do_inflate = 0 if exists $info->{inflate_date} and $info->{inflate_date} == 0;
-
-  if ($do_inflate and ($type eq 'datetime' || $type eq 'date')) {
+  if ($type eq 'datetime' || $type eq 'date') {
     my ($parse, $format) = ("parse_${type}", "format_${type}");
+
+    # This assignment must happen here, otherwise Devel::Cycle treats
+    # the resulting deflator as a circular reference (go figure):
+    #
+    # Cycle #1
+    #     DBICTest::Schema A->{source_registrations} => %B
+    #     %B->{Event} => DBIx::Class::ResultSource::Table C
+    #     DBIx::Class::ResultSource::Table C->{_columns} => %D
+    #     %D->{created_on} => %E
+    #     %E->{_inflate_info} => %F
+    #     %F->{deflate} => &G
+    #     closure &G, $info => $H
+    #     $H => %E
+    #
+    my $floating_tz_ok = $info->{extra}{floating_tz_ok};
+
     $self->inflate_column(
       $column =>
         {
@@ -118,7 +144,14 @@ sub register_column {
           },
           deflate => sub {
             my ($value, $obj) = @_;
-            $value->set_time_zone($timezone) if $timezone;
+            if ($timezone) {
+                warn "You're using a floating timezone, please see the documentation of"
+                  . " DBIx::Class::InflateColumn::DateTime for an explanation"
+                  if ref( $value->time_zone ) eq 'DateTime::TimeZone::Floating'
+                      and not $floating_tz_ok
+                      and not $ENV{DBIC_FLOATING_TZ_OK};
+                $value->set_time_zone($timezone);
+            }
             $obj->_datetime_parser->$format($value);
           },
         }
@@ -138,6 +171,49 @@ sub _datetime_parser {
 1;
 __END__
 
+=head1 USAGE NOTES
+
+If you have a datetime column with the C<timezone> extra setting, and subsenquently 
+create/update this column with a DateTime object in the L<DateTime::TimeZone::Floating>
+timezone, you will get a warning (as there is a very good chance this will not have the
+result you expect). For example:
+
+  __PACKAGE__->add_columns(
+    starts_when => { data_type => 'datetime', extra => { timezone => "America/Chicago" } }
+  );
+
+  my $event = $schema->resultset('EventTZ')->create({
+    starts_at => DateTime->new(year=>2007, month=>12, day=>31, ),
+  });
+
+The warning can be avoided in several ways:
+
+=over
+
+=item Fix your broken code
+
+When calling C<set_time_zone> on a Floating DateTime object, the timezone is simply
+set to the requested value, and B<no time conversion takes place>. It is always a good idea
+to be supply explicit times to the database:
+
+  my $event = $schema->resultset('EventTZ')->create({
+    starts_at => DateTime->new(year=>2007, month=>12, day=>31, time_zone => "America/Chicago" ),
+  });
+
+=item Suppress the check on per-column basis
+
+  __PACKAGE__->add_columns(
+    starts_when => { data_type => 'datetime', extra => { timezone => "America/Chicago", floating_tz_ok => 1 } }
+  );
+
+=item Suppress the check globally
+
+Set the environment variable DBIC_FLOATING_TZ_OK to some true value.
+
+=back
+
+
+
 =head1 SEE ALSO
 
 =over 4
@@ -145,6 +221,10 @@ __END__
 =item More information about the add_columns method, and column metadata, 
       can be found in the documentation for L<DBIx::Class::ResultSource>.
 
+=item Further discussion of problems inherent to the Floating timezone:
+      L<Floating DateTimes|DateTime/Floating_DateTimes> 
+      and L<< $dt->set_time_zone|DateTime/"Set" Methods >>
+
 =back
 
 =head1 AUTHOR