Avoid infinite loop if save point does not exist

AUTHORS

@@ -162,6 +162,7 @@ Peter Valdemar Mørch <peter@morch.com>
 peter: Peter Collingbourne <peter@pcc.me.uk>
 phaylon: Robert Sedlacek <phaylon@dunkelheit.at>
 plu: Johannes Plunien <plu@cpan.org>
+pmooney: Paul Mooney <paul.mooney@net-a-porter.com>
 Possum: Daniel LeWarne <possum@cpan.org>
 pplu: Jose Luis Martinez <jlmartinez@capside.com>
 quicksilver: Jules Bean <jules@jellybean.co.uk>

Changes

@@ -45,6 +45,7 @@ Revision history for DBIx::Class
           create()/populate()
         - Remove spurious exception warping in ::Replicated::execute_reliably
           (RT#113339)
+        - Fix infinite loop on ->svp_release("nonexistent_savepoint") (GH#97)
         - Fix spurious ROLLBACK statements when a TxnScopeGuard fails a commit
           of a transaction with deferred FK checks: a guard is now inactivated
           immediately before the commit is attempted (RT#107159)

lib/DBIx/Class/Storage.pm

@@ -431,12 +431,15 @@ sub svp_release {
 
   if (defined $name) {
     my @stack = @{ $self->savepoints };
-    my $svp;
+    my $svp = '';
 
-    do { $svp = pop @stack } until $svp eq $name;
+    while( $svp ne $name ) {
 
-    $self->throw_exception ("Savepoint '$name' does not exist")
-      unless $svp;
+      $self->throw_exception ("Savepoint '$name' does not exist")
+        unless @stack;
+
+      $svp = pop @stack;
+    }
 
     $self->savepoints(\@stack); # put back what's left
   }

t/storage/savepoints.t

@@ -7,6 +7,7 @@ use Test::More;
 use Test::Exception;
 use DBIx::Class::Optional::Dependencies;
 use DBIx::Class::_Util qw(sigwarn_silencer scope_guard);
+use Scalar::Util 'weaken';
 
 use DBICTest;
 
@@ -240,6 +241,17 @@ for ('', keys %$env2optdep) { SKIP: {
   # make sure a fresh txn will work after above
   $schema->storage->txn_do(sub { ok "noop" } );
 
+### Make sure non-existend savepoint release doesn't infloop itself
+  {
+    weaken( my $s = $schema );
+
+    throws_ok {
+      $s->storage->txn_do(sub { $s->svp_release('wibble') })
+    } qr/Savepoint 'wibble' does not exist/,
+      "Calling svp_release on a non-existant savepoint throws expected error"
+    ;
+  }
+
 ### cleanupz
   $schema->storage->dbh_do(sub { $_[1]->do("DROP TABLE artist") });
 }}