converted tabs to spaces, removed trailing whitespace

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Relationship / BelongsTo.pm

diff --git a/lib/DBIx/Class/Relationship/BelongsTo.pm b/lib/DBIx/Class/Relationship/BelongsTo.pm
index 4acb8fe..535fa75 100644 (file)
--- a/lib/DBIx/Class/Relationship/BelongsTo.pm
+++ b/lib/DBIx/Class/Relationship/BelongsTo.pm
@@ -6,37 +6,60 @@ use warnings;
 sub belongs_to {
   my ($class, $rel, $f_class, $cond, $attrs) = @_;
   eval "require $f_class";
-  # single key relationship
-  if (not defined $cond) {
-    my ($pri, $too_many) = keys %{ $f_class->_primaries };
-    my $acc_type = ($class->_columns->{$rel}) ? 'filter' : 'single';
+  if ($@) {
+    $class->throw_exception($@) unless $@ =~ /Can't locate/;
+  }
+  
+  # no join condition or just a column name
+  if (!ref $cond) {
+    my %f_primaries = map { $_ => 1 } eval { $f_class->primary_columns };
+    $class->throw_exception("Can't infer join condition for ${rel} on ${class}; unable to load ${f_class}")
+      if $@;
+
+    my ($pri, $too_many) = keys %f_primaries;
+    $class->throw_exception("Can't infer join condition for ${rel} on ${class}; ${f_class} has no primary keys")
+      unless defined $pri;
+    $class->throw_exception("Can't infer join condition for ${rel} on ${class}; ${f_class} has multiple primary keys")
+      if $too_many;
+
+    my $fk = defined $cond ? $cond : $rel;
+    $class->throw_exception("Can't infer join condition for ${rel} on ${class}; $fk is not a column")
+      unless $class->has_column($fk);
+
+    my $acc_type = $class->has_column($rel) ? 'filter' : 'single';
     $class->add_relationship($rel, $f_class,
-      { "foreign.${pri}" => "self.${rel}" },
-      { accessor => $acc_type }
+      { "foreign.${pri}" => "self.${fk}" },
+      { accessor => $acc_type, %{$attrs || {}} }
     );
   }
-  # multiple key relationship
-  else {
-    my %f_primaries = %{ $f_class->_primaries };
+  # explicit join condition
+  elsif (ref $cond eq 'HASH') {
     my $cond_rel;
     for (keys %$cond) {
-      $cond_rel->{"foreign.$_"} = "self.".$cond->{$_};
-      # primary key usage checks
-      if (exists $f_primaries{$_}) {
-        delete $f_primaries{$_};
-      }
-      else
-      {
-        $class->throw("non primary key used in join condition: $_");
+      if (m/\./) { # Explicit join condition
+        $cond_rel = $cond;
+        last;
       }
+      $cond_rel->{"foreign.$_"} = "self.".$cond->{$_};
     }
-    $class->throw("not all primary keys used in multi key relationship!") if keys %f_primaries;
+    my $acc_type = (keys %$cond_rel == 1 and $class->has_column($rel)) ? 'filter' : 'single';
     $class->add_relationship($rel, $f_class,
       $cond_rel,
-      { accessor => 'single', %{$attrs ||{}} }
+      { accessor => $acc_type, %{$attrs || {}} }
     );
   }
+  else {
+    $class->throw_exception('third argument for belongs_to must be undef, a column name, or a join condition');
+  }
   return 1;
 }
 
+=head1 AUTHORS
+
+Alexander Hartmaier <Alexander.Hartmaier@t-systems.at>
+
+Matt S. Trout <mst@shadowcatsystems.co.uk>
+
+=cut
+
 1;