Add a clone method to ResultSource, switch obvious spots to it

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultSource.pm

diff --git a/lib/DBIx/Class/ResultSource.pm b/lib/DBIx/Class/ResultSource.pm
index 6fa12c3..053b398 100644 (file)
--- a/lib/DBIx/Class/ResultSource.pm
+++ b/lib/DBIx/Class/ResultSource.pm
@@ -4,7 +4,6 @@ use strict;
 use warnings;
 
 use base 'DBIx::Class::ResultSource::RowParser';
-use mro 'c3';
 
 use DBIx::Class::Carp;
 use DBIx::Class::_Util qw( UNRESOLVABLE_CONDITION dbic_internal_try fail_on_internal_call );
@@ -116,20 +115,72 @@ Creates a new ResultSource object.  Not normally called directly by end users.
 
 =cut
 
-sub new {
-  my ($class, $attrs) = @_;
-  $class = ref $class if ref $class;
-
-  my $new = bless { %{$attrs || {}} }, $class;
-  $new->{resultset_class} ||= 'DBIx::Class::ResultSet';
-  $new->{resultset_attributes} = { %{$new->{resultset_attributes} || {}} };
-  $new->{_ordered_columns} = [ @{$new->{_ordered_columns}||[]}];
-  $new->{_columns} = { %{$new->{_columns}||{}} };
-  $new->{_relationships} = { %{$new->{_relationships}||{}} };
-  $new->{name} ||= "!!NAME NOT SET!!";
-  $new->{_columns_info_loaded} ||= 0;
-  $new->{sqlt_deploy_callback} ||= 'default_sqlt_deploy_hook';
-  return $new;
+{
+  sub new {
+    my ($class, $attrs) = @_;
+    $class = ref $class if ref $class;
+
+    my $self = bless { %{$attrs || {}} }, $class;
+
+
+    DBIx::Class::_ENV_::ASSERT_NO_ERRONEOUS_METAINSTANCE_USE
+      and
+    # a constructor with 'name' as sole arg clearly isn't "inheriting" from anything
+    ( not ( keys(%$self) == 1 and exists $self->{name} ) )
+      and
+    defined CORE::caller(1)
+      and
+    (CORE::caller(1))[3] !~ / ::new$ | ^ DBIx::Class :: (?:
+      ResultSourceProxy::Table::table
+        |
+      ResultSourceProxy::Table::_init_result_source_instance
+        |
+      ResultSource::clone
+    ) $ /x
+      and
+    local $Carp::CarpLevel = $Carp::CarpLevel + 1
+      and
+    Carp::confess("Incorrect instantiation of '$self': you almost certainly wanted to call ->clone() instead");
+
+
+    $self->{resultset_class} ||= 'DBIx::Class::ResultSet';
+    $self->{name} ||= "!!NAME NOT SET!!";
+    $self->{_columns_info_loaded} ||= 0;
+    $self->{sqlt_deploy_callback} ||= 'default_sqlt_deploy_hook';
+
+    $self->{$_} = { %{ $self->{$_} || {} } }
+      for qw( _columns _relationships resultset_attributes );
+
+    $self->{_ordered_columns} = [ @{ $self->{_ordered_columns} || [] } ];
+
+    $self;
+  }
+}
+
+=head2 clone
+
+  $rsrc_instance->clone( atribute_name => overriden_value );
+
+A wrapper around L</new> inheriting any defaults from the callee. This method
+also not normally invoked directly by end users.
+
+=cut
+
+sub clone {
+  my $self = shift;
+
+  $self->new({
+    (
+      (length ref $self)
+        ? %$self
+        : ()
+    ),
+    (
+      (@_ == 1 and ref $_[0] eq 'HASH')
+        ? %{ $_[0] }
+        : @_
+    ),
+  });
 }
 
 =pod
@@ -353,7 +404,10 @@ sub add_columns {
   return $self;
 }
 
-sub add_column { shift->add_columns(@_); } # DO NOT CHANGE THIS TO GLOB
+sub add_column {
+  DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
+  shift->add_columns(@_)
+}
 
 =head2 has_column
 
@@ -578,7 +632,6 @@ sub remove_columns {
   $self->_ordered_columns([ grep { not $to_remove{$_} } @{$self->_ordered_columns} ]);
 }
 
-# DO NOT CHANGE THIS TO A GLOB
 sub remove_column {
   DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
   shift->remove_columns(@_)
@@ -802,6 +855,8 @@ See also L</add_unique_constraint>.
 =cut
 
 sub add_unique_constraints {
+  DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
+
   my $self = shift;
   my @constraints = @_;
 
@@ -1094,12 +1149,15 @@ Store a collection of resultset attributes, that will be set on every
 L<DBIx::Class::ResultSet> produced from this result source.
 
 B<CAVEAT>: C<resultset_attributes> comes with its own set of issues and
-bugs! While C<resultset_attributes> isn't deprecated per se, its usage is
-not recommended!
+bugs! Notably the contents of the attributes are B<entirely static>, which
+greatly hinders composability (things like L<current_source_alias
+|DBIx::Class::ResultSet/current_source_alias> can not possibly be respected).
+While C<resultset_attributes> isn't deprecated per se, you are strongly urged
+to seek alternatives.
 
 Since relationships use attributes to link tables together, the "default"
 attributes you set may cause unpredictable and undesired behavior.  Furthermore,
-the defaults cannot be turned off, so you are stuck with them.
+the defaults B<cannot be turned off>, so you are stuck with them.
 
 In most cases, what you should actually be using are project-specific methods:
 
@@ -2367,7 +2425,7 @@ sub DESTROY {
   # however beware - on older perls the exception seems randomly untrappable
   # due to some weird race condition during thread joining :(((
   local $SIG{__DIE__} if $SIG{__DIE__};
-  local $@;
+  local $@ if DBIx::Class::_ENV_::UNSTABLE_DOLLARAT;
   eval {
     weaken $_[0]->{schema};