Detect and very loudly warn about Return::Multilevel in exception_action()

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

diff --git a/lib/DBIx/Class/_Util.pm b/lib/DBIx/Class/_Util.pm
index c11ee22..091f976 100644 (file)
--- a/lib/DBIx/Class/_Util.pm
+++ b/lib/DBIx/Class/_Util.pm
@@ -4,7 +4,11 @@ package # hide from PAUSE
 use warnings;
 use strict;
 
-use constant SPURIOUS_VERSION_CHECK_WARNINGS => ($] < 5.010 ? 1 : 0);
+use constant SPURIOUS_VERSION_CHECK_WARNINGS => (
+  ( $ENV{DBICTEST_VERSION_WARNS_INDISCRIMINATELY} or $] < 5.010 )
+    ? 1
+    : 0
+);
 
 BEGIN {
   package # hide from pause
@@ -21,8 +25,9 @@ BEGIN {
 
     HAS_ITHREADS => $Config{useithreads} ? 1 : 0,
 
-    # ::Runmode would only be loaded by DBICTest, which in turn implies t/
-    DBICTEST => eval { DBICTest::RunMode->is_author } ? 1 : 0,
+    UNSTABLE_DOLLARAT => ( "$]" < 5.013002 ) ? 1 : 0,
+
+    DBICTEST => $INC{"DBICTest/Util.pm"} ? 1 : 0,
 
     # During 5.13 dev cycle HELEMs started to leak on copy
     # add an escape for these perls ON SMOKERS - a user will still get death
@@ -55,8 +60,10 @@ BEGIN {
 # Carp::Skip to the rescue soon
 use DBIx::Class::Carp '^DBIx::Class|^DBICTest';
 
+use B ();
 use Carp 'croak';
-use Scalar::Util qw(weaken blessed reftype);
+use Storable 'nfreeze';
+use Scalar::Util qw(weaken blessed reftype refaddr);
 use List::Util qw(first);
 use Sub::Quote qw(qsub quote_sub);
 
@@ -64,7 +71,8 @@ use base 'Exporter';
 our @EXPORT_OK = qw(
   sigwarn_silencer modver_gt_or_eq modver_gt_or_eq_and_lt
   fail_on_internal_wantarray fail_on_internal_call
-  refdesc refcount hrefaddr is_exception
+  refdesc refcount hrefaddr
+  scope_guard is_exception detected_reinvoked_destructor
   quote_sub qsub perlstring serialize
   UNRESOLVABLE_CONDITION
 );
@@ -83,7 +91,7 @@ sub sigwarn_silencer ($) {
 
 sub perlstring ($) { q{"}. quotemeta( shift ). q{"} };
 
-sub hrefaddr ($) { sprintf '0x%x', &Scalar::Util::refaddr||0 }
+sub hrefaddr ($) { sprintf '0x%x', &refaddr||0 }
 
 sub refdesc ($) {
   croak "Expecting a reference" if ! length ref $_[0];
@@ -93,23 +101,46 @@ sub refdesc ($) {
   sprintf '%s%s(0x%x)',
     ( defined( $_[1] = blessed $_[0]) ? "$_[1]=" : '' ),
     reftype $_[0],
-    Scalar::Util::refaddr($_[0]),
+    refaddr($_[0]),
   ;
 }
 
 sub refcount ($) {
   croak "Expecting a reference" if ! length ref $_[0];
 
-  require B;
   # No tempvars - must operate on $_[0], otherwise the pad
   # will count as an extra ref
   B::svref_2object($_[0])->REFCNT;
 }
 
 sub serialize ($) {
-  require Storable;
   local $Storable::canonical = 1;
-  Storable::nfreeze($_[0]);
+  nfreeze($_[0]);
+}
+
+sub scope_guard (&) {
+  croak 'Calling scope_guard() in void context makes no sense'
+    if ! defined wantarray;
+
+  # no direct blessing of coderefs - DESTROY is buggy on those
+  bless [ $_[0] ], 'DBIx::Class::_Util::ScopeGuard';
+}
+{
+  package #
+    DBIx::Class::_Util::ScopeGuard;
+
+  sub DESTROY {
+    &DBIx::Class::_Util::detected_reinvoked_destructor;
+
+    local $@ if DBIx::Class::_ENV_::UNSTABLE_DOLLARAT;
+
+    eval {
+      $_[0]->[0]->();
+      1;
+    } or do {
+      Carp::cluck "Execution of scope guard $_[0] resulted in the non-trappable exception:\n\n$@";
+    };
+  }
 }
 
 sub is_exception ($) {
@@ -164,6 +195,54 @@ sub is_exception ($) {
   return $not_blank;
 }
 
+{
+  my $destruction_registry = {};
+
+  sub CLONE {
+    $destruction_registry = { map
+      { defined $_ ? ( refaddr($_) => $_ ) : () }
+      values %$destruction_registry
+    };
+  }
+
+  # This is almost invariably invoked from within DESTROY
+  # throwing exceptions won't work
+  sub detected_reinvoked_destructor {
+
+    # quick "garbage collection" pass - prevents the registry
+    # from slowly growing with a bunch of undef-valued keys
+    defined $destruction_registry->{$_} or delete $destruction_registry->{$_}
+      for keys %$destruction_registry;
+
+    if (! length ref $_[0]) {
+      printf STDERR '%s() expects a blessed reference %s',
+        (caller(0))[3],
+        Carp::longmess,
+      ;
+      return undef; # don't know wtf to do
+    }
+    elsif (! defined $destruction_registry->{ my $addr = refaddr($_[0]) } ) {
+      weaken( $destruction_registry->{$addr} = $_[0] );
+      return 0;
+    }
+    else {
+      carp_unique ( sprintf (
+        'Preventing *MULTIPLE* DESTROY() invocations on %s - an *EXTREMELY '
+      . 'DANGEROUS* condition which is *ALMOST CERTAINLY GLOBAL* within your '
+      . 'application, affecting *ALL* classes without active protection against '
+      . 'this. Diagnose and fix the root cause ASAP!!!%s',
+      refdesc $_[0],
+        ( ( $INC{'Devel/StackTrace.pm'} and ! do { local $@; eval { Devel::StackTrace->VERSION(2) } } )
+          ? " (likely culprit Devel::StackTrace\@@{[ Devel::StackTrace->VERSION ]} found in %INC, http://is.gd/D_ST_refcap)"
+          : ''
+        )
+      ));
+
+      return 1;
+    }
+  }
+}
+
 sub modver_gt_or_eq ($$) {
   my ($mod, $ver) = @_;