X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FRelationship%2FBelongsTo.pm;h=b871266500d85be05a6afdf18a8991d1d47ce66c;hb=a28009914a3e447af53737d503b1953160d146c9;hp=4acb8fe346fa2df76b588a749926d809d4bf96a1;hpb=07037f89d4d9bf97c59a2c083de74f669521da47;p=dbsrgits%2FDBIx-Class-Historic.git

diff --git a/lib/DBIx/Class/Relationship/BelongsTo.pm b/lib/DBIx/Class/Relationship/BelongsTo.pm
index 4acb8fe..b871266 100644
--- a/lib/DBIx/Class/Relationship/BelongsTo.pm
+++ b/lib/DBIx/Class/Relationship/BelongsTo.pm
@@ -1,42 +1,78 @@
-package DBIx::Class::Relationship::BelongsTo;
+package # hide from PAUSE
+    DBIx::Class::Relationship::BelongsTo;
+
+# Documentation for these methods can be found in
+# DBIx::Class::Relationship
 
 use strict;
 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';
+  # no join condition or just a column name
+  if (!ref $cond) {
+    $class->ensure_class_loaded($f_class);
+    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 of $class"
+    ) 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;