X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FStorage%2FTxnScopeGuard.pm;h=111621b1896745548efe49bd936f1c2b4d32d1ba;hb=118b2c36ae7a9174ecc4b22e1fa2c91f8e56dead;hp=06c510cec297fe62d914e50b77b8b1635a2e44fc;hpb=3b7f3eac72dbf39bb9a616ae4884e51f6d872c26;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/Storage/TxnScopeGuard.pm b/lib/DBIx/Class/Storage/TxnScopeGuard.pm
index 06c510c..111621b 100644
--- a/lib/DBIx/Class/Storage/TxnScopeGuard.pm
+++ b/lib/DBIx/Class/Storage/TxnScopeGuard.pm
@@ -2,41 +2,109 @@ package DBIx::Class::Storage::TxnScopeGuard;
 
 use strict;
 use warnings;
+use Scalar::Util qw(weaken blessed refaddr);
+use DBIx::Class;
+use DBIx::Class::_Util qw(is_exception detected_reinvoked_destructor);
+use DBIx::Class::Carp;
+use namespace::clean;
 
 sub new {
   my ($class, $storage) = @_;
 
+  my $guard = {
+    inactivated => 0,
+    storage => $storage,
+  };
+
+  # we are starting with an already set $@ - in order for things to work we need to
+  # be able to recognize it upon destruction - store its weakref
+  # recording it before doing the txn_begin stuff
+  #
+  # FIXME FRAGILE - any eval that fails but *does not* rethrow between here
+  # and the unwind will trample over $@ and invalidate the entire mechanism
+  # There got to be a saner way of doing this...
+  #
+  # Deliberately *NOT* using is_exception - if someone left a misbehaving
+  # antipattern value in $@, it's not our business to whine about it
+  if( defined $@ and length $@ ) {
+    weaken(
+      $guard->{existing_exception_ref} = (length ref $@) ? $@ : \$@
+    );
+  }
+
   $storage->txn_begin;
-  bless [ 0, $storage ], ref $class || $class;
+
+  weaken( $guard->{dbh} = $storage->_dbh );
+
+  bless $guard, ref $class || $class;
+
+  $guard;
 }
 
 sub commit {
   my $self = shift;
 
-  $self->[1]->txn_commit;
-  $self->[0] = 1;
+  $self->{storage}->throw_exception("Refusing to execute multiple commits on scope guard $self")
+    if $self->{inactivated};
+
+  # FIXME - this assumption may be premature: a commit may fail and a rollback
+  # *still* be necessary. Currently I am not aware of such scenarious, but I
+  # also know the deferred constraint handling is *severely* undertested.
+  # Making the change of "fire txn and never come back to this" in order to
+  # address RT#107159, but this *MUST* be reevaluated later.
+  $self->{inactivated} = 1;
+  $self->{storage}->txn_commit;
 }
 
 sub DESTROY {
-  my ($dismiss, $storage) = @{$_[0]};
-
-  return if $dismiss;
-
-  my $exception = $@;
-
-  $DB::single = 1;
-
-  local $@;
-  eval { $storage->txn_rollback };
-  my $rollback_exception = $@;
-  if($rollback_exception) {
-    my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
-
-    $storage->throw_exception(
-      "Transaction aborted: ${exception}. "
-      . "Rollback failed: ${rollback_exception}"
-    ) unless $rollback_exception =~ /$exception_class/;
+  return if &detected_reinvoked_destructor;
+
+  return if $_[0]->{inactivated};
+
+
+  # grab it before we've done volatile stuff below
+  my $current_exception = (
+    is_exception $@
+      and
+    (
+      ! defined $_[0]->{existing_exception_ref}
+        or
+      refaddr( (length ref $@) ? $@ : \$@ ) != refaddr($_[0]->{existing_exception_ref})
+    )
+  )
+    ? $@
+    : undef
+  ;
+
+
+  # if our dbh is not ours anymore, the $dbh weakref will go undef
+  $_[0]->{storage}->_verify_pid unless DBIx::Class::_ENV_::BROKEN_FORK;
+  return unless defined $_[0]->{dbh};
+
+
+  carp 'A DBIx::Class::Storage::TxnScopeGuard went out of scope without explicit commit or error. Rolling back'
+    unless defined $current_exception;
+
+
+  if (
+    my $rollback_exception = $_[0]->{storage}->__delicate_rollback(
+      defined $current_exception
+        ? \$current_exception
+        : ()
+    )
+      and
+    ! defined $current_exception
+  ) {
+    carp (join ' ',
+      "********************* ROLLBACK FAILED!!! ********************",
+      "\nA rollback operation failed after the guard went out of scope.",
+      'This is potentially a disastrous situation, check your data for',
+      "consistency: $rollback_exception"
+    );
   }
+
+  $@ = $current_exception
+    if DBIx::Class::_ENV_::UNSTABLE_DOLLARAT;
 }
 
 1;
@@ -45,7 +113,7 @@ __END__
 
 =head1 NAME
 
-DBIx::Class::Storage::TxnScopeGuard
+DBIx::Class::Storage::TxnScopeGuard - Scope-based transaction handling
 
 =head1 SYNOPSIS
 
@@ -62,20 +130,21 @@ DBIx::Class::Storage::TxnScopeGuard
 =head1 DESCRIPTION
 
 An object that behaves much like L<Scope::Guard>, but hardcoded to do the
-right thing with transactions in DBIx::Class. 
+right thing with transactions in DBIx::Class.
 
 =head1 METHODS
 
 =head2 new
 
-Creating an instance of this class will start a new transaction. Expects a
+Creating an instance of this class will start a new transaction (by
+implicitly calling L<DBIx::Class::Storage/txn_begin>. Expects a
 L<DBIx::Class::Storage> object as its only argument.
 
 =head2 commit
 
 Commit the transaction, and stop guarding the scope. If this method is not
-called (i.e. an exception is thrown) and this object goes out of scope then
-the transaction is rolled back.
+called and this object goes out of scope (e.g. an exception is thrown) then
+the transaction is rolled back, via L<DBIx::Class::Storage/txn_rollback>
 
 =cut
 
@@ -83,13 +152,15 @@ the transaction is rolled back.
 
 L<DBIx::Class::Schema/txn_scope_guard>.
 
-=head1 AUTHOR
+L<Scope::Guard> by chocolateboy (inspiration for this module)
 
-Ash Berlin, 2008.
+=head1 FURTHER QUESTIONS?
 
-Insipred by L<Scope::Guard> by chocolateboy.
+Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
 
-This module is free software. It may be used, redistributed and/or modified
-under the same terms as Perl itself.
+=head1 COPYRIGHT AND LICENSE
 
-=cut
+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>.