X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FSchema.pm;h=d5a8f35832bc3ca135f1f3b2b0b35cdc8b1360ef;hb=f064a2abb15858bb39a141ad50391d4191988d2c;hp=3981b51d5fa6c93536529033160a874b00d02fd1;hpb=f90375dd325063c09f0c07c80239d3b8e9f756f1;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Schema.pm b/lib/DBIx/Class/Schema.pm
index 3981b51..d5a8f35 100644
--- a/lib/DBIx/Class/Schema.pm
+++ b/lib/DBIx/Class/Schema.pm
@@ -3,18 +3,29 @@ package DBIx::Class::Schema;
 use strict;
 use warnings;
 
-use Carp::Clan qw/^DBIx::Class/;
-use Scalar::Util qw/weaken/;
-use File::Spec;
-require Module::Find;
-
-use base qw/DBIx::Class/;
-
-__PACKAGE__->mk_classdata('class_mappings' => {});
-__PACKAGE__->mk_classdata('source_registrations' => {});
-__PACKAGE__->mk_classdata('storage_type' => '::DBI');
-__PACKAGE__->mk_classdata('storage');
-__PACKAGE__->mk_classdata('exception_action');
+use base 'DBIx::Class';
+
+use DBIx::Class::Carp;
+use Try::Tiny;
+use Scalar::Util qw/weaken blessed/;
+use DBIx::Class::_Util qw(
+  refcount quote_sub scope_guard
+  is_exception dbic_internal_try
+  fail_on_internal_call emit_loud_diag
+);
+use Devel::GlobalDestruction;
+use namespace::clean;
+
+__PACKAGE__->mk_group_accessors( inherited => qw( storage exception_action ) );
+__PACKAGE__->mk_classaccessor('storage_type' => '::DBI');
+__PACKAGE__->mk_classaccessor('stacktrace' => $ENV{DBIC_TRACE} || 0);
+__PACKAGE__->mk_classaccessor('default_resultset_attributes' => {});
+
+# These two should have been private from the start but too late now
+# Undocumented on purpose, hopefully it won't ever be necessary to
+# screw with them
+__PACKAGE__->mk_classaccessor('class_mappings' => {});
+__PACKAGE__->mk_classaccessor('source_registrations' => {});
 
 =head1 NAME
 
@@ -25,12 +36,13 @@ DBIx::Class::Schema - composable schemas
   package Library::Schema;
   use base qw/DBIx::Class::Schema/;
 
-  # load Library::Schema::CD, Library::Schema::Book, Library::Schema::DVD
-  __PACKAGE__->load_classes(qw/CD Book DVD/);
+  # load all Result classes in Library/Schema/Result/
+  __PACKAGE__->load_namespaces();
 
-  package Library::Schema::CD;
-  use base qw/DBIx::Class/;
-  __PACKAGE__->load_components(qw/PK::Auto Core/); # for example
+  package Library::Schema::Result::CD;
+  use base qw/DBIx::Class::Core/;
+
+  __PACKAGE__->load_components(qw/InflateColumn::DateTime/); # for example
   __PACKAGE__->table('cd');
 
   # Elsewhere in your code:
@@ -38,12 +50,12 @@ DBIx::Class::Schema - composable schemas
     $dsn,
     $user,
     $password,
-    { AutoCommit => 0 },
+    { AutoCommit => 1 },
   );
 
   my $schema2 = Library::Schema->connect($coderef_returning_dbh);
 
-  # fetch objects using Library::Schema::DVD
+  # fetch objects using Library::Schema::Result::DVD
   my $resultset = $schema1->resultset('DVD')->search( ... );
   my @dvd_objects = $schema2->resultset('DVD')->search( ... );
 
@@ -57,164 +69,236 @@ NB: If you're used to L<Class::DBI> it's worth reading the L</SYNOPSIS>
 carefully, as DBIx::Class does things a little differently. Note in
 particular which module inherits off which.
 
-=head1 METHODS
+=head1 SETUP METHODS
 
-=head2 register_class
+=head2 load_namespaces
 
 =over 4
 
-=item Arguments: $moniker, $component_class
+=item Arguments: %options?
 
 =back
 
-Registers a class which isa DBIx::Class::ResultSourceProxy. Equivalent to
-calling:
-
-  $schema->register_source($moniker, $component_class->result_source_instance);
-
-=cut
-
-sub register_class {
-  my ($self, $moniker, $to_register) = @_;
-  $self->register_source($moniker => $to_register->result_source_instance);
-}
-
-=head2 register_source
-
-=over 4
-
-=item Arguments: $moniker, $result_source
+  package MyApp::Schema;
+  __PACKAGE__->load_namespaces();
 
-=back
+  __PACKAGE__->load_namespaces(
+     result_namespace => 'Res',
+     resultset_namespace => 'RSet',
+     default_resultset_class => '+MyApp::Othernamespace::RSet',
+  );
 
-Registers the L<DBIx::Class::ResultSource> in the schema with the given
-moniker.
+With no arguments, this method uses L<Module::Find> to load all of the
+Result and ResultSet classes under the namespace of the schema from
+which it is called.  For example, C<My::Schema> will by default find
+and load Result classes named C<My::Schema::Result::*> and ResultSet
+classes named C<My::Schema::ResultSet::*>.
 
-=cut
+ResultSet classes are associated with Result class of the same name.
+For example, C<My::Schema::Result::CD> will get the ResultSet class
+C<My::Schema::ResultSet::CD> if it is present.
 
-sub register_source {
-  my ($self, $moniker, $source) = @_;
+Both Result and ResultSet namespaces are configurable via the
+C<result_namespace> and C<resultset_namespace> options.
 
-  %$source = %{ $source->new( { %$source, source_name => $moniker }) };
+Another option, C<default_resultset_class> specifies a custom default
+ResultSet class for Result classes with no corresponding ResultSet.
 
-  my %reg = %{$self->source_registrations};
-  $reg{$moniker} = $source;
-  $self->source_registrations(\%reg);
+All of the namespace and classname options are by default relative to
+the schema classname.  To specify a fully-qualified name, prefix it
+with a literal C<+>.  For example, C<+Other::NameSpace::Result>.
 
-  $source->schema($self);
+=head3 Warnings
 
-  weaken($source->{schema}) if ref($self);
-  if ($source->result_class) {
-    my %map = %{$self->class_mappings};
-    $map{$source->result_class} = $moniker;
-    $self->class_mappings(\%map);
-  }
-}
+You will be warned if ResultSet classes are discovered for which there
+are no matching Result classes like this:
 
-sub _unregister_source {
-    my ($self, $moniker) = @_;
-    my %reg = %{$self->source_registrations}; 
+  load_namespaces found ResultSet class $classname with no corresponding Result class
 
-    my $source = delete $reg{$moniker};
-    $self->source_registrations(\%reg);
-    if ($source->result_class) {
-        my %map = %{$self->class_mappings};
-        delete $map{$source->result_class};
-        $self->class_mappings(\%map);
-    }
-}
+If a ResultSource instance is found to already have a ResultSet class set
+using L<resultset_class|DBIx::Class::ResultSource/resultset_class> to some
+other class, you will be warned like this:
 
-=head2 class
+  We found ResultSet class '$rs_class' for '$result_class', but it seems
+  that you had already set '$result_class' to use '$rs_set' instead
 
-=over 4
+=head3 Examples
 
-=item Arguments: $moniker
+  # load My::Schema::Result::CD, My::Schema::Result::Artist,
+  #    My::Schema::ResultSet::CD, etc...
+  My::Schema->load_namespaces;
 
-=item Return Value: $classname
+  # Override everything to use ugly names.
+  # In this example, if there is a My::Schema::Res::Foo, but no matching
+  #   My::Schema::RSets::Foo, then Foo will have its
+  #   resultset_class set to My::Schema::RSetBase
+  My::Schema->load_namespaces(
+    result_namespace => 'Res',
+    resultset_namespace => 'RSets',
+    default_resultset_class => 'RSetBase',
+  );
 
-=back
+  # Put things in other namespaces
+  My::Schema->load_namespaces(
+    result_namespace => '+Some::Place::Results',
+    resultset_namespace => '+Another::Place::RSets',
+  );
 
-Retrieves the result class name for the given moniker. For example:
+To search multiple namespaces for either Result or ResultSet classes,
+use an arrayref of namespaces for that option.  In the case that the
+same result (or resultset) class exists in multiple namespaces, later
+entries in the list of namespaces will override earlier ones.
 
-  my $class = $schema->class('CD');
+  My::Schema->load_namespaces(
+    # My::Schema::Results_C::Foo takes precedence over My::Schema::Results_B::Foo :
+    result_namespace => [ 'Results_A', 'Results_B', 'Results_C' ],
+    resultset_namespace => [ '+Some::Place::RSets', 'RSets' ],
+  );
 
 =cut
 
-sub class {
-  my ($self, $moniker) = @_;
-  return $self->source($moniker)->result_class;
+# Pre-pends our classname to the given relative classname or
+#   class namespace, unless there is a '+' prefix, which will
+#   be stripped.
+sub _expand_relative_name {
+  my ($class, $name) = @_;
+  $name =~ s/^\+// or $name = "${class}::${name}";
+  return $name;
 }
 
-=head2 source
+# Finds all modules in the supplied namespace, or if omitted in the
+# namespace of $class. Untaints all findings as they can be assumed
+# to be safe
+sub _findallmod {
+  require Module::Find;
+  return map
+    { $_ =~ /(.+)/ }   # untaint result
+    Module::Find::findallmod( $_[1] || ref $_[0] || $_[0] )
+  ;
+}
 
-=over 4
+# returns a hash of $shortname => $fullname for every package
+# found in the given namespaces ($shortname is with the $fullname's
+# namespace stripped off)
+sub _map_namespaces {
+  my ($me, $namespaces) = @_;
 
-=item Arguments: $moniker
+  my %res;
+  for my $ns (@$namespaces) {
+    $res{ substr($_, length "${ns}::") } = $_
+      for $me->_findallmod($ns);
+  }
 
-=item Return Value: $result_source
+  \%res;
+}
 
-=back
+# returns the result_source_instance for the passed class/object,
+# or dies with an informative message (used by load_namespaces)
+sub _ns_get_rsrc_instance {
+  my $me = shift;
+  my $rs_class = ref ($_[0]) || $_[0];
+
+  return dbic_internal_try {
+    $rs_class->result_source_instance
+  } catch {
+    $me->throw_exception (
+      "Attempt to load_namespaces() class $rs_class failed - are you sure this is a real Result Class?: $_"
+    );
+  };
+}
 
-  my $source = $schema->source('Book');
+sub load_namespaces {
+  my ($class, %args) = @_;
 
-Returns the L<DBIx::Class::ResultSource> object for the registered moniker.
+  my $result_namespace = delete $args{result_namespace} || 'Result';
+  my $resultset_namespace = delete $args{resultset_namespace} || 'ResultSet';
 
-=cut
+  my $default_resultset_class = delete $args{default_resultset_class};
 
-sub source {
-  my ($self, $moniker) = @_;
-  my $sreg = $self->source_registrations;
-  return $sreg->{$moniker} if exists $sreg->{$moniker};
-
-  # if we got here, they probably passed a full class name
-  my $mapped = $self->class_mappings->{$moniker};
-  $self->throw_exception("Can't find source for ${moniker}")
-    unless $mapped && exists $sreg->{$mapped};
-  return $sreg->{$mapped};
-}
+  $default_resultset_class = $class->_expand_relative_name($default_resultset_class)
+    if $default_resultset_class;
 
-=head2 sources
+  $class->throw_exception('load_namespaces: unknown option(s): '
+    . join(q{,}, map { qq{'$_'} } keys %args))
+      if scalar keys %args;
 
-=over 4
+  for my $arg ($result_namespace, $resultset_namespace) {
+    $arg = [ $arg ] if ( $arg and ! ref $arg );
 
-=item Return Value: @source_monikers
+    $class->throw_exception('load_namespaces: namespace arguments must be '
+      . 'a simple string or an arrayref')
+        if ref($arg) ne 'ARRAY';
 
-=back
+    $_ = $class->_expand_relative_name($_) for (@$arg);
+  }
 
-Returns the source monikers of all source registrations on this schema.
-For example:
+  my $results_by_source_name = $class->_map_namespaces($result_namespace);
+  my $resultsets_by_source_name = $class->_map_namespaces($resultset_namespace);
 
-  my @source_monikers = $schema->sources;
+  my @to_register;
+  {
+    no warnings qw/redefine/;
+    local *Class::C3::reinitialize = sub { } if DBIx::Class::_ENV_::OLD_MRO;
+    use warnings qw/redefine/;
 
-=cut
+    # ensure classes are loaded and attached in inheritance order
+    for my $result_class (values %$results_by_source_name) {
+      $class->ensure_class_loaded($result_class);
+    }
+    my %inh_idx;
+    my @source_names_by_subclass_last = sort {
 
-sub sources { return keys %{shift->source_registrations}; }
+      ($inh_idx{$a} ||=
+        scalar @{mro::get_linear_isa( $results_by_source_name->{$a} )}
+      )
 
-=head2 storage
+          <=>
 
-  my $storage = $schema->storage;
+      ($inh_idx{$b} ||=
+        scalar @{mro::get_linear_isa( $results_by_source_name->{$b} )}
+      )
 
-Returns the L<DBIx::Class::Storage> object for this Schema.
+    } keys(%$results_by_source_name);
 
-=head2 resultset
+    foreach my $source_name (@source_names_by_subclass_last) {
+      my $result_class = $results_by_source_name->{$source_name};
 
-=over 4
+      my $preset_resultset_class = $class->_ns_get_rsrc_instance ($result_class)->resultset_class;
+      my $found_resultset_class = delete $resultsets_by_source_name->{$source_name};
 
-=item Arguments: $moniker
+      if($preset_resultset_class && $preset_resultset_class ne 'DBIx::Class::ResultSet') {
+        if($found_resultset_class && $found_resultset_class ne $preset_resultset_class) {
+          carp "We found ResultSet class '$found_resultset_class' matching '$results_by_source_name->{$source_name}', but it seems "
+             . "that you had already set the '$results_by_source_name->{$source_name}' resultet to '$preset_resultset_class' instead";
+        }
+      }
+      # elsif - there may be *no* default_resultset_class, in which case we fallback to
+      # DBIx::Class::Resultset and there is nothing to check
+      elsif($found_resultset_class ||= $default_resultset_class) {
+        $class->ensure_class_loaded($found_resultset_class);
+        if(!$found_resultset_class->isa("DBIx::Class::ResultSet")) {
+            carp "load_namespaces found ResultSet class '$found_resultset_class' that does not subclass DBIx::Class::ResultSet";
+        }
 
-=item Return Value: $result_set
+        $class->_ns_get_rsrc_instance ($result_class)->resultset_class($found_resultset_class);
+      }
 
-=back
+      my $source_name = $class->_ns_get_rsrc_instance ($result_class)->source_name || $source_name;
 
-  my $rs = $schema->resultset('DVD');
+      push(@to_register, [ $source_name, $result_class ]);
+    }
+  }
 
-Returns the L<DBIx::Class::ResultSet> object for the registered moniker.
+  foreach (sort keys %$resultsets_by_source_name) {
+    carp "load_namespaces found ResultSet class '$resultsets_by_source_name->{$_}' "
+        .'with no corresponding Result class';
+  }
 
-=cut
+  Class::C3->reinitialize if DBIx::Class::_ENV_::OLD_MRO;
 
-sub resultset {
-  my ($self, $moniker) = @_;
-  return $self->source($moniker)->resultset;
+  $class->register_class(@$_) for (@to_register);
+
+  return;
 }
 
 =head2 load_classes
@@ -225,6 +309,11 @@ sub resultset {
 
 =back
 
+L</load_classes> is an alternative method to L</load_namespaces>, both of
+which serve similar purposes, each with different advantages and disadvantages.
+In the general case you should use L</load_namespaces>, unless you need to
+be able to specify that only specific classes are loaded at runtime.
+
 With no arguments, this method uses L<Module::Find> to find all classes under
 the schema's namespace. Otherwise, this method loads the classes you specify
 (using L<use>), and registers them (using L</"register_class">).
@@ -233,6 +322,13 @@ It is possible to comment out classes with a leading C<#>, but note that perl
 will think it's a mistake (trying to use a comment in a qw list), so you'll
 need to add C<no warnings 'qw';> before your load_classes call.
 
+If any classes found do not appear to be Result class files, you will
+get the following warning:
+
+   Failed to load $comp_class. Can't find source_name method. Is
+   $comp_class really a full DBIC result class? Fix it, move it elsewhere,
+   or make your load_classes call more specific.
+
 Example:
 
   My::Schema->load_classes(); # loads My::Schema::CD, My::Schema::Artist,
@@ -275,431 +371,323 @@ sub load_classes {
     }
   } else {
     my @comp = map { substr $_, length "${class}::"  }
-                 Module::Find::findallmod($class);
+                 $class->_findallmod($class);
     $comps_for{$class} = \@comp;
   }
 
   my @to_register;
   {
     no warnings qw/redefine/;
-    local *Class::C3::reinitialize = sub { };
+    local *Class::C3::reinitialize = sub { } if DBIx::Class::_ENV_::OLD_MRO;
+    use warnings qw/redefine/;
+
     foreach my $prefix (keys %comps_for) {
       foreach my $comp (@{$comps_for{$prefix}||[]}) {
         my $comp_class = "${prefix}::${comp}";
-        { # try to untaint module name. mods where this fails
-          # are left alone so we don't have to change the old behavior
-          no locale; # localized \w doesn't untaint expression
-          if ( $comp_class =~ m/^( (?:\w+::)* \w+ )$/x ) {
-            $comp_class = $1;
-          }
-        }
         $class->ensure_class_loaded($comp_class);
 
-        $comp = $comp_class->source_name || $comp;
-#  $DB::single = 1;
+        my $snsub = $comp_class->can('source_name');
+        if(! $snsub ) {
+          carp "Failed to load $comp_class. Can't find source_name method. Is $comp_class really a full DBIC result class? Fix it, move it elsewhere, or make your load_classes call more specific.";
+          next;
+        }
+        $comp = $snsub->($comp_class) || $comp;
+
         push(@to_register, [ $comp, $comp_class ]);
       }
     }
   }
-  Class::C3->reinitialize;
+  Class::C3->reinitialize if DBIx::Class::_ENV_::OLD_MRO;
 
   foreach my $to (@to_register) {
     $class->register_class(@$to);
-    #  if $class->can('result_source_instance');
   }
 }
 
-=head2 load_namespaces
+=head2 storage_type
 
 =over 4
 
-=item Arguments: %options?
+=item Arguments: $storage_type|{$storage_type, \%args}
 
-=back
+=item Return Value: $storage_type|{$storage_type, \%args}
 
-This is an alternative to L</load_classes> above which assumes an alternative
-layout for automatic class loading.  It assumes that all result
-classes are underneath a sub-namespace of the schema called C<Result>, any
-corresponding ResultSet classes are underneath a sub-namespace of the schema
-called C<ResultSet>.
+=item Default value: DBIx::Class::Storage::DBI
 
-Both of the sub-namespaces are configurable if you don't like the defaults,
-via the options C<result_namespace> and C<resultset_namespace>.
+=back
 
-If (and only if) you specify the option C<default_resultset_class>, any found
-Result classes for which we do not find a corresponding
-ResultSet class will have their C<resultset_class> set to
-C<default_resultset_class>.
+Set the storage class that will be instantiated when L</connect> is called.
+If the classname starts with C<::>, the prefix C<DBIx::Class::Storage> is
+assumed by L</connect>.
 
-C<load_namespaces> takes care of calling C<resultset_class> for you where
-neccessary if you didn't do it for yourself.
+You want to use this to set subclasses of L<DBIx::Class::Storage::DBI>
+in cases where the appropriate subclass is not autodetected.
 
-All of the namespace and classname options to this method are relative to
-the schema classname by default.  To specify a fully-qualified name, prefix
-it with a literal C<+>.
+If your storage type requires instantiation arguments, those are
+defined as a second argument in the form of a hashref and the entire
+value needs to be wrapped into an arrayref or a hashref.  We support
+both types of refs here in order to play nice with your
+Config::[class] or your choice. See
+L<DBIx::Class::Storage::DBI::Replicated> for an example of this.
 
-Examples:
+=head2 default_resultset_attributes
 
-  # load My::Schema::Result::CD, My::Schema::Result::Artist,
-  #    My::Schema::ResultSet::CD, etc...
-  My::Schema->load_namespaces;
+=over 4
 
-  # Override everything to use ugly names.
-  # In this example, if there is a My::Schema::Res::Foo, but no matching
-  #   My::Schema::RSets::Foo, then Foo will have its
-  #   resultset_class set to My::Schema::RSetBase
-  My::Schema->load_namespaces(
-    result_namespace => 'Res',
-    resultset_namespace => 'RSets',
-    default_resultset_class => 'RSetBase',
-  );
+=item Arguments: L<\%attrs|DBIx::Class::ResultSet/ATTRIBUTES>
 
-  # Put things in other namespaces
-  My::Schema->load_namespaces(
-    result_namespace => '+Some::Place::Results',
-    resultset_namespace => '+Another::Place::RSets',
-  );
+=item Return Value: L<\%attrs|DBIx::Class::ResultSet/ATTRIBUTES>
 
-If you'd like to use multiple namespaces of each type, simply use an arrayref
-of namespaces for that option.  In the case that the same result
-(or resultset) class exists in multiple namespaces, the latter entries in
-your list of namespaces will override earlier ones.
+=item Default value: None
 
-  My::Schema->load_namespaces(
-    # My::Schema::Results_C::Foo takes precedence over My::Schema::Results_B::Foo :
-    result_namespace => [ 'Results_A', 'Results_B', 'Results_C' ],
-    resultset_namespace => [ '+Some::Place::RSets', 'RSets' ],
-  );
+=back
 
-=cut
+Like L<DBIx::Class::ResultSource/resultset_attributes> stores a collection
+of resultset attributes, to be used as defaults for B<every> ResultSet
+instance schema-wide. The same list of CAVEATS and WARNINGS applies, with
+the extra downside of these defaults being practically inescapable: you will
+B<not> be able to derive a ResultSet instance with these attributes unset.
 
-# Pre-pends our classname to the given relative classname or
-#   class namespace, unless there is a '+' prefix, which will
-#   be stripped.
-sub _expand_relative_name {
-  my ($class, $name) = @_;
-  return if !$name;
-  $name = $class . '::' . $name if ! ($name =~ s/^\+//);
-  return $name;
-}
+Example:
 
-# returns a hash of $shortname => $fullname for every package
-#  found in the given namespaces ($shortname is with the $fullname's
-#  namespace stripped off)
-sub _map_namespaces {
-  my ($class, @namespaces) = @_;
-
-  my @results_hash;
-  foreach my $namespace (@namespaces) {
-    push(
-      @results_hash,
-      map { (substr($_, length "${namespace}::"), $_) }
-      Module::Find::findallmod($namespace)
-    );
-  }
+   package My::Schema;
+   use base qw/DBIx::Class::Schema/;
+   __PACKAGE__->default_resultset_attributes( { software_limit => 1 } );
 
-  @results_hash;
-}
+=head2 exception_action
 
-sub load_namespaces {
-  my ($class, %args) = @_;
+=over 4
 
-  my $result_namespace = delete $args{result_namespace} || 'Result';
-  my $resultset_namespace = delete $args{resultset_namespace} || 'ResultSet';
-  my $default_resultset_class = delete $args{default_resultset_class};
+=item Arguments: $code_reference
 
-  $class->throw_exception('load_namespaces: unknown option(s): '
-    . join(q{,}, map { qq{'$_'} } keys %args))
-      if scalar keys %args;
+=item Return Value: $code_reference
 
-  $default_resultset_class
-    = $class->_expand_relative_name($default_resultset_class);
+=item Default value: None
 
-  for my $arg ($result_namespace, $resultset_namespace) {
-    $arg = [ $arg ] if !ref($arg) && $arg;
+=back
 
-    $class->throw_exception('load_namespaces: namespace arguments must be '
-      . 'a simple string or an arrayref')
-        if ref($arg) ne 'ARRAY';
+When L</throw_exception> is invoked and L</exception_action> is set to a code
+reference, this reference will be called instead of
+L<DBIx::Class::Exception/throw>, with the exception message passed as the only
+argument.
 
-    $_ = $class->_expand_relative_name($_) for (@$arg);
-  }
+Your custom throw code B<must> rethrow the exception, as L</throw_exception> is
+an integral part of DBIC's internal execution control flow.
 
-  my %results = $class->_map_namespaces(@$result_namespace);
-  my %resultsets = $class->_map_namespaces(@$resultset_namespace);
+Example:
 
-  my @to_register;
-  {
-    no warnings 'redefine';
-    local *Class::C3::reinitialize = sub { };
-    use warnings 'redefine';
+   package My::Schema;
+   use base qw/DBIx::Class::Schema/;
+   use My::ExceptionClass;
+   __PACKAGE__->exception_action(sub { My::ExceptionClass->throw(@_) });
+   __PACKAGE__->load_classes;
 
-    foreach my $result (keys %results) {
-      my $result_class = $results{$result};
-      $class->ensure_class_loaded($result_class);
-      $result_class->source_name($result) unless $result_class->source_name;
-
-      my $rs_class = delete $resultsets{$result};
-      my $rs_set = $result_class->resultset_class;
-      if($rs_set && $rs_set ne 'DBIx::Class::ResultSet') {
-        if($rs_class && $rs_class ne $rs_set) {
-          warn "We found ResultSet class '$rs_class' for '$result', but it seems "
-             . "that you had already set '$result' to use '$rs_set' instead";
-        }
-      }
-      elsif($rs_class ||= $default_resultset_class) {
-        $class->ensure_class_loaded($rs_class);
-        $result_class->resultset_class($rs_class);
-      }
+   # or:
+   my $schema_obj = My::Schema->connect( .... );
+   $schema_obj->exception_action(sub { My::ExceptionClass->throw(@_) });
 
-      push(@to_register, [ $result_class->source_name, $result_class ]);
-    }
-  }
+=head2 stacktrace
 
-  foreach (sort keys %resultsets) {
-    warn "load_namespaces found ResultSet class $_ with no "
-      . 'corresponding Result class';
-  }
+=over 4
 
-  Class::C3->reinitialize;
-  $class->register_class(@$_) for (@to_register);
+=item Arguments: boolean
 
-  return;
-}
+=back
 
-=head2 compose_connection (DEPRECATED)
+Whether L</throw_exception> should include stack trace information.
+Defaults to false normally, but defaults to true if C<$ENV{DBIC_TRACE}>
+is true.
 
-=over 4
+=head2 sqlt_deploy_hook
 
-=item Arguments: $target_namespace, @db_info
+=over
 
-=item Return Value: $new_schema
+=item Arguments: $sqlt_schema
 
 =back
 
-DEPRECATED. You probably wanted compose_namespace.
+An optional sub which you can declare in your own Schema class that will get
+passed the L<SQL::Translator::Schema> object when you deploy the schema via
+L</create_ddl_dir> or L</deploy>.
 
-Actually, you probably just wanted to call connect.
+For an example of what you can do with this, see
+L<DBIx::Class::Manual::Cookbook/Adding Indexes And Functions To Your SQL>.
 
-=for hidden due to deprecation
+Note that sqlt_deploy_hook is called by L</deployment_statements>, which in turn
+is called before L</deploy>. Therefore the hook can be used only to manipulate
+the L<SQL::Translator::Schema> object before it is turned into SQL fed to the
+database. If you want to execute post-deploy statements which can not be generated
+by L<SQL::Translator>, the currently suggested method is to overload L</deploy>
+and use L<dbh_do|DBIx::Class::Storage::DBI/dbh_do>.
 
-Calls L<DBIx::Class::Schema/"compose_namespace"> to the target namespace,
-calls L<DBIx::Class::Schema/connection> with @db_info on the new schema,
-then injects the L<DBix::Class::ResultSetProxy> component and a
-resultset_instance classdata entry on all the new classes, in order to support
-$target_namespaces::$class->search(...) method calls.
+=head1 METHODS
 
-This is primarily useful when you have a specific need for class method access
-to a connection. In normal usage it is preferred to call
-L<DBIx::Class::Schema/connect> and use the resulting schema object to operate
-on L<DBIx::Class::ResultSet> objects with L<DBIx::Class::Schema/resultset> for
-more information.
+=head2 connect
 
-=cut
+=over 4
 
-{
-  my $warn;
+=item Arguments: @connectinfo
 
-  sub compose_connection {
-    my ($self, $target, @info) = @_;
+=item Return Value: $new_schema
 
-    warn "compose_connection deprecated as of 0.08000" unless $warn++;
+=back
 
-    my $base = 'DBIx::Class::ResultSetProxy';
-    eval "require ${base};";
-    $self->throw_exception
-      ("No arguments to load_classes and couldn't load ${base} ($@)")
-        if $@;
-  
-    if ($self eq $target) {
-      # Pathological case, largely caused by the docs on early C::M::DBIC::Plain
-      foreach my $moniker ($self->sources) {
-        my $source = $self->source($moniker);
-        my $class = $source->result_class;
-        $self->inject_base($class, $base);
-        $class->mk_classdata(resultset_instance => $source->resultset);
-        $class->mk_classdata(class_resolver => $self);
-      }
-      $self->connection(@info);
-      return $self;
-    }
-  
-    my $schema = $self->compose_namespace($target, $base);
-    {
-      no strict 'refs';
-      *{"${target}::schema"} = sub { $schema };
-    }
-  
-    $schema->connection(@info);
-    foreach my $moniker ($schema->sources) {
-      my $source = $schema->source($moniker);
-      my $class = $source->result_class;
-      #warn "$moniker $class $source ".$source->storage;
-      $class->mk_classdata(result_source_instance => $source);
-      $class->mk_classdata(resultset_instance => $source->resultset);
-      $class->mk_classdata(class_resolver => $schema);
-    }
-    return $schema;
-  }
-}
+Creates and returns a new Schema object. The connection info set on it
+is used to create a new instance of the storage backend and set it on
+the Schema object.
 
-=head2 compose_namespace
+See L<DBIx::Class::Storage::DBI/"connect_info"> for DBI-specific
+syntax on the C<@connectinfo> argument, or L<DBIx::Class::Storage> in
+general.
 
-=over 4
+Note that C<connect_info> expects an arrayref of arguments, but
+C<connect> does not. C<connect> wraps its arguments in an arrayref
+before passing them to C<connect_info>.
 
-=item Arguments: $target_namespace, $additional_base_class?
+=head3 Overloading
 
-=item Return Value: $new_schema
-
-=back
-
-For each L<DBIx::Class::ResultSource> in the schema, this method creates a
-class in the target namespace (e.g. $target_namespace::CD,
-$target_namespace::Artist) that inherits from the corresponding classes
-attached to the current schema.
-
-It also attaches a corresponding L<DBIx::Class::ResultSource> object to the
-new $schema object. If C<$additional_base_class> is given, the new composed
-classes will inherit from first the corresponding classe from the current
-schema then the base class.
-
-For example, for a schema with My::Schema::CD and My::Schema::Artist classes,
-
-  $schema->compose_namespace('My::DB', 'Base::Class');
-  print join (', ', @My::DB::CD::ISA) . "\n";
-  print join (', ', @My::DB::Artist::ISA) ."\n";
-
-will produce the output
-
-  My::Schema::CD, Base::Class
-  My::Schema::Artist, Base::Class
+C<connect> is a convenience method. It is equivalent to calling
+$schema->clone->connection(@connectinfo). To write your own overloaded
+version, overload L</connection> instead.
 
 =cut
 
-sub compose_namespace {
-  my ($self, $target, $base) = @_;
-  my %reg = %{ $self->source_registrations };
-  my %target;
-  my %map;
-  my $schema = $self->clone;
-  {
-    no warnings qw/redefine/;
-    local *Class::C3::reinitialize = sub { };
-    foreach my $moniker ($schema->sources) {
-      my $source = $schema->source($moniker);
-      my $target_class = "${target}::${moniker}";
-      $self->inject_base(
-        $target_class => $source->result_class, ($base ? $base : ())
-      );
-      $source->result_class($target_class);
-      $target_class->result_source_instance($source)
-        if $target_class->can('result_source_instance');
-    }
-  }
-  Class::C3->reinitialize();
-  {
-    no strict 'refs';
-    foreach my $meth (qw/class source resultset/) {
-      *{"${target}::${meth}"} =
-        sub { shift->schema->$meth(@_) };
-    }
-  }
-  return $schema;
+sub connect {
+  DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
+  shift->clone->connection(@_);
 }
 
-=head2 setup_connection_class
+=head2 resultset
 
 =over 4
 
-=item Arguments: $target, @info
+=item Arguments: L<$source_name|DBIx::Class::ResultSource/source_name>
+
+=item Return Value: L<$resultset|DBIx::Class::ResultSet>
 
 =back
 
-Sets up a database connection class to inject between the schema and the
-subclasses that the schema creates.
+  my $rs = $schema->resultset('DVD');
+
+Returns the L<DBIx::Class::ResultSet> object for the registered source
+name.
 
 =cut
 
-sub setup_connection_class {
-  my ($class, $target, @info) = @_;
-  $class->inject_base($target => 'DBIx::Class::DB');
-  #$target->load_components('DB');
-  $target->connection(@info);
+sub resultset {
+  my ($self, $source_name) = @_;
+  $self->throw_exception('resultset() expects a source name')
+    unless defined $source_name;
+  return $self->source($source_name)->resultset;
 }
 
-=head2 storage_type
+=head2 sources
 
 =over 4
 
-=item Arguments: $storage_type
-
-=item Return Value: $storage_type
+=item Return Value: L<@source_names|DBIx::Class::ResultSource/source_name>
 
 =back
 
-Set the storage class that will be instantiated when L</connect> is called.
-If the classname starts with C<::>, the prefix C<DBIx::Class::Storage> is
-assumed by L</connect>.  Defaults to C<::DBI>,
-which is L<DBIx::Class::Storage::DBI>.
+  my @source_names = $schema->sources;
 
-You want to use this to hardcoded subclasses of L<DBIx::Class::Storage::DBI>
-in cases where the appropriate subclass is not autodetected, such as when
-dealing with MSSQL via L<DBD::Sybase>, in which case you'd set it to
-C<::DBI::Sybase::MSSQL>.
+Lists names of all the sources registered on this Schema object.
 
-=head2 connection
+=cut
+
+sub sources { keys %{shift->source_registrations} }
+
+=head2 source
 
 =over 4
 
-=item Arguments: @args
+=item Arguments: L<$source_name|DBIx::Class::ResultSource/source_name>
 
-=item Return Value: $new_schema
+=item Return Value: L<$result_source|DBIx::Class::ResultSource>
 
 =back
 
-Instantiates a new Storage object of type
-L<DBIx::Class::Schema/"storage_type"> and passes the arguments to
-$storage->connect_info. Sets the connection in-place on the schema.
+  my $source = $schema->source('Book');
 
-See L<DBIx::Class::Storage::DBI/"connect_info"> for DBI-specific syntax,
-or L<DBIx::Class::Storage> in general.
+Returns the L<DBIx::Class::ResultSource> object for the registered
+source name.
 
 =cut
 
-sub connection {
-  my ($self, @info) = @_;
-  return $self if !@info && $self->storage;
-  my $storage_class = $self->storage_type;
-  $storage_class = 'DBIx::Class::Storage'.$storage_class
-    if $storage_class =~ m/^::/;
-  eval "require ${storage_class};";
-  $self->throw_exception(
-    "No arguments to load_classes and couldn't load ${storage_class} ($@)"
-  ) if $@;
-  my $storage = $storage_class->new($self);
-  $storage->connect_info(\@info);
-  $self->storage($storage);
-  $self->on_connect() if($self->can('on_connect'));
-  return $self;
+sub source {
+  my ($self, $source_name) = @_;
+
+  $self->throw_exception("source() expects a source name")
+    unless $source_name;
+
+  my $source_registrations;
+
+  my $rsrc =
+    ( $source_registrations = $self->source_registrations )->{$source_name}
+      ||
+    # if we got here, they probably passed a full class name
+    $source_registrations->{ $self->class_mappings->{$source_name} || '' }
+      ||
+    $self->throw_exception( "Can't find source for ${source_name}" )
+  ;
+
+  # DO NOT REMOVE:
+  # We need to prevent alterations of pre-existing $@ due to where this call
+  # sits in the overall stack ( *unless* of course there is an actual error
+  # to report ). set_mro does alter $@ (and yes - it *can* throw an exception)
+  # We do not use local because set_mro *can* throw an actual exception
+  # We do not use a try/catch either, as on one hand it would slow things
+  # down for no reason (we would always rethrow), but also because adding *any*
+  # try/catch block below will segfault various threading tests on older perls
+  # ( which in itself is a FIXME but ENOTIMETODIG )
+  my $old_dollarat = $@;
+
+  no strict 'refs';
+  mro::set_mro($_, 'c3') for
+    grep
+      {
+        # some pseudo-sources do not have a result/resultset yet
+        defined $_
+          and
+        (
+          (
+            ${"${_}::__INITIAL_MRO_UPON_DBIC_LOAD__"}
+              ||= mro::get_mro($_)
+          )
+            ne
+          'c3'
+        )
+      }
+      map
+        { length ref $_ ? ref $_ : $_ }
+        ( $rsrc, $rsrc->result_class, $rsrc->resultset_class )
+  ;
+
+  # DO NOT REMOVE - see comment above
+  $@ = $old_dollarat;
+
+  $rsrc;
 }
 
-=head2 connect
+=head2 class
 
 =over 4
 
-=item Arguments: @info
+=item Arguments: L<$source_name|DBIx::Class::ResultSource/source_name>
 
-=item Return Value: $new_schema
+=item Return Value: $classname
 
 =back
 
-This is a convenience method. It is equivalent to calling
-$schema->clone->connection(@info). See L</connection> and L</clone> for more
-information.
+  my $class = $schema->class('CD');
+
+Retrieves the Result class name for the given source name.
 
 =cut
 
-sub connect { shift->clone->connection(@_) }
+sub class {
+  return shift->source(shift)->result_class;
+}
 
 =head2 txn_do
 
@@ -718,6 +706,14 @@ See L<DBIx::Class::Storage/"txn_do"> for more information.
 This interface is preferred over using the individual methods L</txn_begin>,
 L</txn_commit>, and L</txn_rollback> below.
 
+WARNING: If you are connected with C<< AutoCommit => 0 >> the transaction is
+considered nested, and you will still need to call L</txn_commit> to write your
+changes when appropriate. You will also want to connect with C<< auto_savepoint =>
+1 >> to get partial rollback to work, if the storage driver for your database
+supports it.
+
+Connecting with C<< AutoCommit => 1 >> is recommended.
+
 =cut
 
 sub txn_do {
@@ -729,11 +725,27 @@ sub txn_do {
   $self->storage->txn_do(@_);
 }
 
+=head2 txn_scope_guard
+
+Runs C<txn_scope_guard> on the schema's storage. See
+L<DBIx::Class::Storage/txn_scope_guard>.
+
+=cut
+
+sub txn_scope_guard {
+  my $self = shift;
+
+  $self->storage or $self->throw_exception
+    ('txn_scope_guard called on $schema without storage');
+
+  $self->storage->txn_scope_guard(@_);
+}
+
 =head2 txn_begin
 
 Begins a transaction (does nothing if AutoCommit is off). Equivalent to
 calling $schema->storage->txn_begin. See
-L<DBIx::Class::Storage::DBI/"txn_begin"> for more information.
+L<DBIx::Class::Storage/"txn_begin"> for more information.
 
 =cut
 
@@ -749,7 +761,7 @@ sub txn_begin {
 =head2 txn_commit
 
 Commits the current transaction. Equivalent to calling
-$schema->storage->txn_commit. See L<DBIx::Class::Storage::DBI/"txn_commit">
+$schema->storage->txn_commit. See L<DBIx::Class::Storage/"txn_commit">
 for more information.
 
 =cut
@@ -767,7 +779,7 @@ sub txn_commit {
 
 Rolls back the current transaction. Equivalent to calling
 $schema->storage->txn_rollback. See
-L<DBIx::Class::Storage::DBI/"txn_rollback"> for more information.
+L<DBIx::Class::Storage/"txn_rollback"> for more information.
 
 =cut
 
@@ -780,112 +792,318 @@ sub txn_rollback {
   $self->storage->txn_rollback;
 }
 
-=head2 clone
+=head2 storage
+
+  my $storage = $schema->storage;
+
+Returns the L<DBIx::Class::Storage> object for this Schema. Grab this
+if you want to turn on SQL statement debugging at runtime, or set the
+quote character. For the default storage, the documentation can be
+found in L<DBIx::Class::Storage::DBI>.
+
+=head2 populate
 
 =over 4
 
-=item Return Value: $new_schema
+=item Arguments: L<$source_name|DBIx::Class::ResultSource/source_name>, [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
+
+=item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
 
 =back
 
-Clones the schema and its associated result_source objects and returns the
-copy.
+A convenience shortcut to L<DBIx::Class::ResultSet/populate>. Equivalent to:
+
+ $schema->resultset($source_name)->populate([...]);
+
+=over 4
+
+=item NOTE
+
+The context of this method call has an important effect on what is
+submitted to storage. In void context data is fed directly to fastpath
+insertion routines provided by the underlying storage (most often
+L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
+L<insert|DBIx::Class::Row/insert> calls on the
+L<Result|DBIx::Class::Manual::ResultClass> class, including any
+augmentation of these methods provided by components. For example if you
+are using something like L<DBIx::Class::UUIDColumns> to create primary
+keys for you, you will find that your PKs are empty.  In this case you
+will have to explicitly force scalar or list context in order to create
+those values.
+
+=back
 
 =cut
 
-sub clone {
-  my ($self) = @_;
-  my $clone = { (ref $self ? %$self : ()) };
-  bless $clone, (ref $self || $self);
+sub populate {
+  DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
+
+  my ($self, $name, $data) = @_;
+  my $rs = $self->resultset($name)
+    or $self->throw_exception("'$name' is not a resultset");
+
+  return $rs->populate($data);
+}
+
+=head2 connection
 
-  foreach my $moniker ($self->sources) {
-    my $source = $self->source($moniker);
-    my $new = $source->new($source);
-    $clone->register_source($moniker => $new);
+=over 4
+
+=item Arguments: @args
+
+=item Return Value: $self
+
+=back
+
+Similar to L</connect> except sets the storage object and connection
+data B<in-place> on C<$self>. You should probably be calling
+L</connect> to get a properly L<cloned|/clone> Schema object instead.
+
+=head3 Overloading
+
+Overload C<connection> to change the behaviour of C<connect>.
+
+=cut
+
+sub connection {
+  my ($self, @info) = @_;
+  return $self if !@info && $self->storage;
+
+  my ($storage_class, $args) = ref $self->storage_type
+    ? $self->_normalize_storage_type($self->storage_type)
+    : $self->storage_type
+  ;
+
+  $storage_class =~ s/^::/DBIx::Class::Storage::/;
+
+  dbic_internal_try {
+    $self->ensure_class_loaded ($storage_class);
   }
-  $clone->storage->set_schema($clone) if $clone->storage;
-  return $clone;
+  catch {
+    $self->throw_exception(
+      "Unable to load storage class ${storage_class}: $_"
+    );
+  };
+
+  my $storage = $storage_class->new( $self => $args||{} );
+  $storage->connect_info(\@info);
+  $self->storage($storage);
+  return $self;
 }
 
-=head2 populate
+sub _normalize_storage_type {
+  my ($self, $storage_type) = @_;
+  if(ref $storage_type eq 'ARRAY') {
+    return @$storage_type;
+  } elsif(ref $storage_type eq 'HASH') {
+    return %$storage_type;
+  } else {
+    $self->throw_exception('Unsupported REFTYPE given: '. ref $storage_type);
+  }
+}
+
+=head2 compose_namespace
 
 =over 4
 
-=item Arguments: $source_name, \@data;
+=item Arguments: $target_namespace, $additional_base_class?
+
+=item Return Value: $new_schema
 
 =back
 
-Pass this method a resultsource name, and an arrayref of
-arrayrefs. The arrayrefs should contain a list of column names,
-followed by one or many sets of matching data for the given columns. 
+For each L<DBIx::Class::ResultSource> in the schema, this method creates a
+class in the target namespace (e.g. $target_namespace::CD,
+$target_namespace::Artist) that inherits from the corresponding classes
+attached to the current schema.
+
+It also attaches a corresponding L<DBIx::Class::ResultSource> object to the
+new $schema object. If C<$additional_base_class> is given, the new composed
+classes will inherit from first the corresponding class from the current
+schema then the base class.
 
-In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
-to insert the data, as this is a fast method. However, insert_bulk currently
-assumes that your datasets all contain the same type of values, using scalar
-references in a column in one row, and not in another will probably not work.
+For example, for a schema with My::Schema::CD and My::Schema::Artist classes,
 
-Otherwise, each set of data is inserted into the database using
-L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
-objects is returned.
+  $schema->compose_namespace('My::DB', 'Base::Class');
+  print join (', ', @My::DB::CD::ISA) . "\n";
+  print join (', ', @My::DB::Artist::ISA) ."\n";
 
-i.e.,
+will produce the output
 
-  $schema->populate('Artist', [
-    [ qw/artistid name/ ],
-    [ 1, 'Popular Band' ],
-    [ 2, 'Indie Band' ],
-    ...
-  ]);
+  My::Schema::CD, Base::Class
+  My::Schema::Artist, Base::Class
 
 =cut
 
-sub populate {
-  my ($self, $name, $data) = @_;
-  my $rs = $self->resultset($name);
-  my @names = @{shift(@$data)};
-  if(defined wantarray) {
-    my @created;
-    foreach my $item (@$data) {
-      my %create;
-      @create{@names} = @$item;
-      push(@created, $rs->create(\%create));
+sub compose_namespace {
+  my ($self, $target, $base) = @_;
+
+  my $schema = $self->clone;
+
+  $schema->source_registrations({});
+
+  # the original class-mappings must remain - otherwise
+  # reverse_relationship_info will not work
+  #$schema->class_mappings({});
+
+  {
+    no warnings qw/redefine/;
+    local *Class::C3::reinitialize = sub { } if DBIx::Class::_ENV_::OLD_MRO;
+    use warnings qw/redefine/;
+
+    foreach my $source_name ($self->sources) {
+      my $orig_source = $self->source($source_name);
+
+      my $target_class = "${target}::${source_name}";
+      $self->inject_base($target_class, $orig_source->result_class, ($base || ()) );
+
+      $schema->register_source(
+        $source_name,
+        $orig_source->clone(
+          result_class => $target_class
+        ),
+      );
     }
-    return @created;
+
+    # Legacy stuff, not inserting INDIRECT assertions
+    quote_sub "${target}::${_}" => "shift->schema->$_(\@_)"
+      for qw(class source resultset);
   }
-  $self->storage->insert_bulk($self->source($name)->from, \@names, $data);
+
+  Class::C3->reinitialize() if DBIx::Class::_ENV_::OLD_MRO;
+
+  # Give each composed class yet another *schema-less* source copy
+  # this is used for the freeze/thaw cycle
+  #
+  # This is not covered by any tests directly, but is indirectly exercised
+  # in t/cdbi/sweet/08pager by re-setting the schema on an existing object
+  # FIXME - there is likely a much cheaper way to take care of this
+  for my $source_name ($self->sources) {
+
+    my $target_class = "${target}::${source_name}";
+
+    $target_class->result_source_instance(
+      $self->source($source_name)->clone(
+        result_class => $target_class,
+        schema => ( ref $schema || $schema ),
+      )
+    );
+  }
+
+  return $schema;
 }
 
-=head2 exception_action
+# LEGACY: The intra-call to this was removed in 66d9ef6b and then
+# the sub was de-documented way later in 249963d4. No way to be sure
+# nothing on darkpan is calling it directly, so keeping as-is
+sub setup_connection_class {
+  my ($class, $target, @info) = @_;
+  $class->inject_base($target => 'DBIx::Class::DB');
+  #$target->load_components('DB');
+  $target->connection(@info);
+}
+
+=head2 svp_begin
+
+Creates a new savepoint (does nothing outside a transaction).
+Equivalent to calling $schema->storage->svp_begin.  See
+L<DBIx::Class::Storage/"svp_begin"> for more information.
+
+=cut
+
+sub svp_begin {
+  my ($self, $name) = @_;
+
+  $self->storage or $self->throw_exception
+    ('svp_begin called on $schema without storage');
+
+  $self->storage->svp_begin($name);
+}
+
+=head2 svp_release
+
+Releases a savepoint (does nothing outside a transaction).
+Equivalent to calling $schema->storage->svp_release.  See
+L<DBIx::Class::Storage/"svp_release"> for more information.
+
+=cut
+
+sub svp_release {
+  my ($self, $name) = @_;
+
+  $self->storage or $self->throw_exception
+    ('svp_release called on $schema without storage');
+
+  $self->storage->svp_release($name);
+}
+
+=head2 svp_rollback
+
+Rollback to a savepoint (does nothing outside a transaction).
+Equivalent to calling $schema->storage->svp_rollback.  See
+L<DBIx::Class::Storage/"svp_rollback"> for more information.
+
+=cut
+
+sub svp_rollback {
+  my ($self, $name) = @_;
+
+  $self->storage or $self->throw_exception
+    ('svp_rollback called on $schema without storage');
+
+  $self->storage->svp_rollback($name);
+}
+
+=head2 clone
 
 =over 4
 
-=item Arguments: $code_reference
+=item Arguments: %attrs?
+
+=item Return Value: $new_schema
 
 =back
 
-If C<exception_action> is set for this class/object, L</throw_exception>
-will prefer to call this code reference with the exception as an argument,
-rather than its normal <croak> action.
+Clones the schema and its associated result_source objects and returns the
+copy. The resulting copy will have the same attributes as the source schema,
+except for those attributes explicitly overridden by the provided C<%attrs>.
 
-Your subroutine should probably just wrap the error in the exception
-object/class of your choosing and rethrow.  If, against all sage advice,
-you'd like your C<exception_action> to suppress a particular exception
-completely, simply have it return true.
+=cut
 
-Example:
+sub clone {
+  my $self = shift;
 
-   package My::Schema;
-   use base qw/DBIx::Class::Schema/;
-   use My::ExceptionClass;
-   __PACKAGE__->exception_action(sub { My::ExceptionClass->throw(@_) });
-   __PACKAGE__->load_classes;
+  my $clone = {
+      (ref $self ? %$self : ()),
+      (@_ == 1 && ref $_[0] eq 'HASH' ? %{ $_[0] } : @_),
+  };
+  bless $clone, (ref $self || $self);
 
-   # or:
-   my $schema_obj = My::Schema->connect( .... );
-   $schema_obj->exception_action(sub { My::ExceptionClass->throw(@_) });
+  $clone->$_(undef) for qw/class_mappings source_registrations storage/;
+
+  $clone->_copy_state_from($self);
+
+  return $clone;
+}
 
-   # suppress all exceptions, like a moron:
-   $schema_obj->exception_action(sub { 1 });
+# Needed in Schema::Loader - if you refactor, please make a compatibility shim
+# -- Caelum
+sub _copy_state_from {
+  my ($self, $from) = @_;
+
+  $self->class_mappings({ %{$from->class_mappings} });
+  $self->source_registrations({ %{$from->source_registrations} });
+
+  # we use extra here as we want to leave the class_mappings as they are
+  # but overwrite the source_registrations entry with the new source
+  $self->register_extra_source( $_ => $from->source($_) )
+    for $from->sources;
+
+  if ($from->storage) {
+    $self->storage($from->storage);
+    $self->storage->set_schema($self);
+  }
+}
 
 =head2 throw_exception
 
@@ -895,38 +1113,100 @@ Example:
 
 =back
 
-Throws an exception. Defaults to using L<Carp::Clan> to report errors from
-user's perspective.  See L</exception_action> for details on overriding
-this method's behavior.
+Throws an exception. Obeys the exemption rules of L<DBIx::Class::Carp> to report
+errors from outer-user's perspective. See L</exception_action> for details on overriding
+this method's behavior.  If L</stacktrace> is turned on, C<throw_exception>'s
+default behavior will provide a detailed stack trace.
 
 =cut
 
 sub throw_exception {
-  my $self = shift;
-  croak @_ if !$self->exception_action || !$self->exception_action->(@_);
+  my ($self, @args) = @_;
+
+  if (
+    ! DBIx::Class::_Util::in_internal_try()
+      and
+    my $act = $self->exception_action
+  ) {
+
+    my $guard_disarmed;
+
+    my $guard = scope_guard {
+      return if $guard_disarmed;
+      emit_loud_diag( emit_dups => 1, msg => "
+
+                    !!! DBIx::Class INTERNAL PANIC !!!
+
+The exception_action() handler installed on '$self'
+aborted the stacktrace below via a longjmp (either via Return::Multilevel or
+plain goto, or Scope::Upper or something equally nefarious). There currently
+is nothing safe DBIx::Class can do, aside from displaying this error. A future
+version ( 0.082900, when available ) will reduce the cases in which the
+handler is invoked, but this is neither a complete solution, nor can it do
+anything for other software that might be affected by a similar problem.
+
+                      !!! FIX YOUR ERROR HANDLING !!!
+
+This guard was activated starting",
+      );
+    };
+
+    dbic_internal_try {
+      # if it throws - good, we'll assign to @args in the end
+      # if it doesn't - do different things depending on RV truthiness
+      if( $act->(@args) ) {
+        $args[0] = (
+          "Invocation of the exception_action handler installed on $self did *not*"
+        .' result in an exception. DBIx::Class is unable to function without a reliable'
+        .' exception mechanism, ensure your exception_action does not hide exceptions'
+        ." (original error: $args[0])"
+        );
+      }
+      else {
+        carp_unique (
+          "The exception_action handler installed on $self returned false instead"
+        .' of throwing an exception. This behavior has been deprecated, adjust your'
+        .' handler to always rethrow the supplied error'
+        );
+      }
+
+      1;
+    }
+    catch {
+      # We call this to get the necessary warnings emitted and disregard the RV
+      # as it's definitely an exception if we got as far as this catch{} block
+      is_exception(
+        $args[0] = $_
+      );
+    };
+
+    # Done guarding against https://github.com/PerlDancer/Dancer2/issues/1125
+    $guard_disarmed = 1;
+  }
+
+  DBIx::Class::Exception->throw( $args[0], $self->stacktrace );
 }
 
-=head2 deploy (EXPERIMENTAL)
+=head2 deploy
 
 =over 4
 
-=item Arguments: $sqlt_args, $dir
+=item Arguments: \%sqlt_args, $dir
 
 =back
 
 Attempts to deploy the schema to the current storage using L<SQL::Translator>.
 
-Note that this feature is currently EXPERIMENTAL and may not work correctly
-across all databases, or fully handle complex relationships. Saying that, it
-has been used successfully by many people, including the core dev team.
+See L<SQL::Translator/METHODS> for a list of values for C<\%sqlt_args>.
+The most common value for this would be C<< { add_drop_table => 1 } >>
+to have the SQL produced include a C<DROP TABLE> statement for each table
+created. For quoting purposes supply C<quote_identifiers>.
 
-See L<SQL::Translator/METHODS> for a list of values for C<$sqlt_args>. The most
-common value for this would be C<< { add_drop_table => 1, } >> to have the SQL
-produced include a DROP TABLE statement for each table created.
-
-Additionally, the DBIx::Class parser accepts a C<sources> parameter as a hash 
-ref or an array ref, containing a list of source to deploy. If present, then 
-only the sources listed will get deployed.
+Additionally, the DBIx::Class parser accepts a C<sources> parameter as a hash
+ref or an array ref, containing a list of source to deploy. If present, then
+only the sources listed will get deployed. Furthermore, you can use the
+C<add_fk_index> parser parameter to prevent the parser from creating an index for each
+FK.
 
 =cut
 
@@ -936,44 +1216,45 @@ sub deploy {
   $self->storage->deploy($self, undef, $sqltargs, $dir);
 }
 
-=head2 create_ddl_dir (EXPERIMENTAL)
+=head2 deployment_statements
 
 =over 4
 
-=item Arguments: \@databases, $version, $directory, $preversion, $sqlt_args
+=item Arguments: See L<DBIx::Class::Storage::DBI/deployment_statements>
+
+=item Return Value: $listofstatements
 
 =back
 
-Creates an SQL file based on the Schema, for each of the specified
-database types, in the given directory. Given a previous version number,
-this will also create a file containing the ALTER TABLE statements to
-transform the previous schema into the current one. Note that these
-statements may contain DROP TABLE or DROP COLUMN statements that can
-potentially destroy data.
+A convenient shortcut to
+C<< $self->storage->deployment_statements($self, @args) >>.
+Returns the statements used by L</deploy> and
+L<DBIx::Class::Storage/deploy>.
 
-The file names are created using the C<ddl_filename> method below, please
-override this method in your schema if you would like a different file
-name format. For the ALTER file, the same format is used, replacing
-$version in the name with "$preversion-$version".
+=cut
 
-If no arguments are passed, then the following default values are used:
+sub deployment_statements {
+  my $self = shift;
 
-=over 4
+  $self->throw_exception("Can't generate deployment statements without a storage")
+    if not $self->storage;
 
-=item databases  - ['MySQL', 'SQLite', 'PostgreSQL']
+  $self->storage->deployment_statements($self, @_);
+}
 
-=item version    - $schema->VERSION
+=head2 create_ddl_dir
 
-=item directory  - './'
+=over 4
 
-=item preversion - <none>
+=item Arguments: See L<DBIx::Class::Storage::DBI/create_ddl_dir>
 
 =back
 
-Note that this feature is currently EXPERIMENTAL and may not work correctly
-across all databases, or fully handle complex relationships.
+A convenient shortcut to
+C<< $self->storage->create_ddl_dir($self, @args) >>.
 
-WARNING: Please check all SQL files created, before applying them.
+Creates an SQL file based on the Schema, for each of the specified
+database types, in the given directory.
 
 =cut
 
@@ -984,15 +1265,17 @@ sub create_ddl_dir {
   $self->storage->create_ddl_dir($self, @_);
 }
 
-=head2 ddl_filename (EXPERIMENTAL)
+=head2 ddl_filename
 
 =over 4
 
-=item Arguments: $directory, $database-type, $version, $preversion
+=item Arguments: $database-type, $version, $directory, $preversion
+
+=item Return Value: $normalised_filename
 
 =back
 
-  my $filename = $table->ddl_filename($type, $dir, $version, $preversion)
+  my $filename = $table->ddl_filename($type, $version, $dir, $preversion)
 
 This method is called by C<create_ddl_dir> to compose a file name out of
 the supplied directory, database type and version number. The default file
@@ -1001,27 +1284,369 @@ name format is: C<$dir$schema-$version-$type.sql>.
 You may override this method in your schema if you wish to use a different
 format.
 
+ WARNING
+
+ Prior to DBIx::Class version 0.08100 this method had a different signature:
+
+    my $filename = $table->ddl_filename($type, $dir, $version, $preversion)
+
+ In recent versions variables $dir and $version were reversed in order to
+ bring the signature in line with other Schema/Storage methods. If you
+ really need to maintain backward compatibility, you can do the following
+ in any overriding methods:
+
+    ($dir, $version) = ($version, $dir) if ($DBIx::Class::VERSION < 0.08100);
+
 =cut
 
 sub ddl_filename {
-    my ($self, $type, $dir, $version, $pversion) = @_;
+  my ($self, $type, $version, $dir, $preversion) = @_;
+
+  $version = "$preversion-$version" if $preversion;
 
-    my $filename = ref($self);
-    $filename =~ s/::/-/;
-    $filename = File::Spec->catfile($dir, "$filename-$version-$type.sql");
-    $filename =~ s/$version/$pversion-$version/ if($pversion);
+  my $class = blessed($self) || $self;
+  $class =~ s/::/-/g;
 
-    return $filename;
+  return "$dir/$class-$version-$type.sql";
 }
 
-1;
+=head2 thaw
+
+Provided as the recommended way of thawing schema objects. You can call
+C<Storable::thaw> directly if you wish, but the thawed objects will not have a
+reference to any schema, so are rather useless.
+
+=cut
+
+sub thaw {
+  my ($self, $obj) = @_;
+  local $DBIx::Class::ResultSourceHandle::thaw_schema = $self;
+  return Storable::thaw($obj);
+}
+
+=head2 freeze
+
+This doesn't actually do anything beyond calling L<nfreeze|Storable/SYNOPSIS>,
+it is just provided here for symmetry.
+
+=cut
+
+sub freeze {
+  return Storable::nfreeze($_[1]);
+}
+
+=head2 dclone
+
+=over 4
+
+=item Arguments: $object
+
+=item Return Value: dcloned $object
+
+=back
+
+Recommended way of dcloning L<DBIx::Class::Row> and L<DBIx::Class::ResultSet>
+objects so their references to the schema object
+(which itself is B<not> cloned) are properly maintained.
+
+=cut
+
+sub dclone {
+  my ($self, $obj) = @_;
+  local $DBIx::Class::ResultSourceHandle::thaw_schema = $self;
+  return Storable::dclone($obj);
+}
+
+=head2 schema_version
+
+Returns the current schema class' $VERSION in a normalised way.
+
+=cut
+
+sub schema_version {
+  my ($self) = @_;
+  my $class = ref($self)||$self;
+
+  # does -not- use $schema->VERSION
+  # since that varies in results depending on if version.pm is installed, and if
+  # so the perl or XS versions. If you want this to change, bug the version.pm
+  # author to make vpp and vxs behave the same.
+
+  my $version;
+  {
+    no strict 'refs';
+    $version = ${"${class}::VERSION"};
+  }
+  return $version;
+}
+
+
+=head2 register_class
+
+=over 4
+
+=item Arguments: $source_name, $component_class
+
+=back
+
+This method is called by L</load_namespaces> and L</load_classes> to install the found classes into your Schema. You should be using those instead of this one.
+
+You will only need this method if you have your Result classes in
+files which are not named after the packages (or all in the same
+file). You may also need it to register classes at runtime.
+
+Registers a class which isa DBIx::Class::ResultSourceProxy. Equivalent to
+calling:
+
+  $schema->register_source($source_name, $component_class->result_source_instance);
+
+=cut
+
+sub register_class {
+  my ($self, $source_name, $to_register) = @_;
+  $self->register_source($source_name => $to_register->result_source_instance);
+}
+
+=head2 register_source
+
+=over 4
+
+=item Arguments: $source_name, L<$result_source|DBIx::Class::ResultSource>
 
-=head1 AUTHORS
+=back
+
+This method is called by L</register_class>.
+
+Registers the L<DBIx::Class::ResultSource> in the schema with the given
+source name.
+
+=cut
+
+sub register_source { shift->_register_source(@_) }
+
+=head2 unregister_source
+
+=over 4
+
+=item Arguments: $source_name
+
+=back
+
+Removes the L<DBIx::Class::ResultSource> from the schema for the given source name.
+
+=cut
+
+sub unregister_source { shift->_unregister_source(@_) }
+
+=head2 register_extra_source
+
+=over 4
+
+=item Arguments: $source_name, L<$result_source|DBIx::Class::ResultSource>
+
+=back
+
+As L</register_source> but should be used if the result class already
+has a source and you want to register an extra one.
+
+=cut
+
+sub register_extra_source { shift->_register_source(@_, { extra => 1 }) }
+
+sub _register_source {
+  my ($self, $source_name, $supplied_rsrc, $params) = @_;
+
+  my $derived_rsrc = $supplied_rsrc->clone({
+    source_name => $source_name,
+  });
+
+  # Do not move into the clone-hashref above: there are things
+  # on CPAN that do hook 'sub schema' </facepalm>
+  # https://metacpan.org/source/LSAUNDERS/DBIx-Class-Preview-1.000003/lib/DBIx/Class/ResultSource/Table/Previewed.pm#L9-38
+  $derived_rsrc->schema($self);
+
+  weaken $derived_rsrc->{schema}
+    if length ref($self);
+
+  my %reg = %{$self->source_registrations};
+  $reg{$source_name} = $derived_rsrc;
+  $self->source_registrations(\%reg);
+
+  return $derived_rsrc if $params->{extra};
+
+  my( $result_class, $result_class_level_rsrc );
+  if (
+    $result_class = $derived_rsrc->result_class
+      and
+    # There are known cases where $rs_class is *ONLY* an inflator, without
+    # any hint of a rsrc (e.g. DBIx::Class::KiokuDB::EntryProxy)
+    $result_class_level_rsrc = dbic_internal_try { $result_class->result_source_instance }
+  ) {
+    my %map = %{$self->class_mappings};
+
+    carp (
+      "$result_class already had a registered source which was replaced by "
+    . 'this call. Perhaps you wanted register_extra_source(), though it is '
+    . 'more likely you did something wrong.'
+    ) if (
+      exists $map{$result_class}
+        and
+      $map{$result_class} ne $source_name
+        and
+      $result_class_level_rsrc != $supplied_rsrc
+    );
+
+    $map{$result_class} = $source_name;
+    $self->class_mappings(\%map);
+  }
+
+  $derived_rsrc;
+}
+
+my $global_phase_destroy;
+sub DESTROY {
+  ### NO detected_reinvoked_destructor check
+  ### This code very much relies on being called multuple times
+
+  return if $global_phase_destroy ||= in_global_destruction;
+
+  my $self = shift;
+  my $srcs = $self->source_registrations;
+
+  for my $source_name (keys %$srcs) {
+    # find first source that is not about to be GCed (someone other than $self
+    # holds a reference to it) and reattach to it, weakening our own link
+    #
+    # during global destruction (if we have not yet bailed out) this should throw
+    # which will serve as a signal to not try doing anything else
+    # however beware - on older perls the exception seems randomly untrappable
+    # due to some weird race condition during thread joining :(((
+    if (length ref $srcs->{$source_name} and refcount($srcs->{$source_name}) > 1) {
+      local $SIG{__DIE__} if $SIG{__DIE__};
+      local $@ if DBIx::Class::_ENV_::UNSTABLE_DOLLARAT;
+      eval {
+        $srcs->{$source_name}->schema($self);
+        weaken $srcs->{$source_name};
+        1;
+      } or do {
+        $global_phase_destroy = 1;
+      };
+
+      last;
+    }
+  }
+
+  # Dummy NEXTSTATE ensuring the all temporaries on the stack are garbage
+  # collected before leaving this scope. Depending on the code above, this
+  # may very well be just a preventive measure guarding future modifications
+  undef;
+}
+
+sub _unregister_source {
+    my ($self, $source_name) = @_;
+    my %reg = %{$self->source_registrations};
+
+    my $source = delete $reg{$source_name};
+    $self->source_registrations(\%reg);
+    if ($source->result_class) {
+        my %map = %{$self->class_mappings};
+        delete $map{$source->result_class};
+        $self->class_mappings(\%map);
+    }
+}
 
-Matt S. Trout <mst@shadowcatsystems.co.uk>
 
-=head1 LICENSE
+=head2 compose_connection (DEPRECATED)
 
-You may distribute this code under the same terms as Perl itself.
+=over 4
+
+=item Arguments: $target_namespace, @db_info
+
+=item Return Value: $new_schema
+
+=back
+
+DEPRECATED. You probably wanted compose_namespace.
+
+Actually, you probably just wanted to call connect.
+
+=begin hidden
+
+(hidden due to deprecation)
+
+Calls L<DBIx::Class::Schema/"compose_namespace"> to the target namespace,
+calls L<DBIx::Class::Schema/connection> with @db_info on the new schema,
+then injects the L<DBix::Class::ResultSetProxy> component and a
+resultset_instance classdata entry on all the new classes, in order to support
+$target_namespaces::$class->search(...) method calls.
+
+This is primarily useful when you have a specific need for class method access
+to a connection. In normal usage it is preferred to call
+L<DBIx::Class::Schema/connect> and use the resulting schema object to operate
+on L<DBIx::Class::ResultSet> objects with L<DBIx::Class::Schema/resultset> for
+more information.
+
+=end hidden
+
+=cut
+
+sub compose_connection {
+  my ($self, $target, @info) = @_;
+
+  carp_once "compose_connection deprecated as of 0.08000"
+    unless $INC{"DBIx/Class/CDBICompat.pm"};
+
+  dbic_internal_try {
+    require DBIx::Class::ResultSetProxy;
+  }
+  catch {
+    $self->throw_exception
+      ("No arguments to load_classes and couldn't load DBIx::Class::ResultSetProxy ($_)")
+  };
+
+  if ($self eq $target) {
+    # Pathological case, largely caused by the docs on early C::M::DBIC::Plain
+    foreach my $source_name ($self->sources) {
+      my $source = $self->source($source_name);
+      my $class = $source->result_class;
+      $self->inject_base($class, 'DBIx::Class::ResultSetProxy');
+      $class->mk_classaccessor(resultset_instance => $source->resultset);
+      $class->mk_classaccessor(class_resolver => $self);
+    }
+    $self->connection(@info);
+    return $self;
+  }
+
+  my $schema = $self->compose_namespace($target, 'DBIx::Class::ResultSetProxy');
+  quote_sub "${target}::schema", '$s', { '$s' => \$schema };
+
+  $schema->connection(@info);
+  foreach my $source_name ($schema->sources) {
+    my $source = $schema->source($source_name);
+    my $class = $source->result_class;
+    #warn "$source_name $class $source ".$source->storage;
+
+    $class->mk_group_accessors( inherited => [ result_source_instance => '_result_source' ] );
+    # explicit set-call, avoid mro update lag
+    $class->set_inherited( result_source_instance => $source );
+
+    $class->mk_classaccessor(resultset_instance => $source->resultset);
+    $class->mk_classaccessor(class_resolver => $schema);
+  }
+  return $schema;
+}
+
+=head1 FURTHER QUESTIONS?
+
+Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
+
+=head1 COPYRIGHT AND LICENSE
+
+This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
+by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
+redistribute it and/or modify it under the same terms as the
+L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.
 
 =cut
+
+1;