X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FSQL%2FAbstract.pm;h=48a2f5b0810c89367f07f2d7e3baf71f09bf328d;hb=a3e3e6a18;hp=56bd63133101e4378461a926531943847bc1aaec;hpb=966200cc8a0d73449caac4beb3a7f3c60580b0de;p=dbsrgits%2FSQL-Abstract.git

diff --git a/lib/SQL/Abstract.pm b/lib/SQL/Abstract.pm
index 56bd631..48a2f5b 100644
--- a/lib/SQL/Abstract.pm
+++ b/lib/SQL/Abstract.pm
@@ -16,6 +16,11 @@ BEGIN {
   else {
     require mro;
   }
+
+  *SQL::Abstract::_ENV_::DETECT_AUTOGENERATED_STRINGIFICATION = $ENV{SQLA_ISVALUE_IGNORE_AUTOGENERATED_STRINGIFICATION}
+    ? sub () { 0 }
+    : sub () { 1 }
+  ;
 }
 
 #======================================================================
@@ -98,8 +103,6 @@ sub is_plain_value ($) {
       # intersted in are much more limited than the fullblown thing, and
       # this is a very hot piece of code
       (
-        # FIXME - DBI needs fixing to stringify regardless of DBD
-        #
         # simply using ->can('(""') can leave behind stub methods that
         # break actually using the overload later (see L<perldiag/Stub
         # found while resolving method "%s" overloading "%s" in package
@@ -108,9 +111,15 @@ sub is_plain_value ($) {
         # either has stringification which DBI SHOULD prefer out of the box
         grep { *{ (qq[${_}::(""]) }{CODE} } @{ $_[2] = mro::get_linear_isa( $_[1] ) }
           or
-        # has nummification and fallback is *not* disabled
+        # has nummification or boolification, AND fallback is *not* disabled
         (
-          grep { *{"${_}::(0+"}{CODE} } @{ mro::get_linear_isa( $_[1] ) }
+          SQL::Abstract::_ENV_::DETECT_AUTOGENERATED_STRINGIFICATION
+            and
+          (
+            grep { *{"${_}::(0+"}{CODE} } @{$_[2]}
+              or
+            grep { *{"${_}::(bool"}{CODE} } @{$_[2]}
+          )
             and
           (
             # no fallback specified at all
@@ -2151,6 +2160,48 @@ module:
 On failure returns C<undef>, on sucess returns a B<scalar> reference
 to the original supplied argument.
 
+=over
+
+=item * Note
+
+The stringification overloading detection is rather advanced: it takes
+into consideration not only the presence of a C<""> overload, but if that
+fails also checks for enabled
+L<autogenerated versions of C<"">|overload/Magic Autogeneration>, based
+on either C<0+> or C<bool>.
+
+Unfortunately testing in the field indicates that this
+detection B<< may tickle a latent bug in perl versions before 5.018 >>,
+but only when very large numbers of stringifying objects are involved.
+At the time of writing ( Sep 2014 ) there is no clear explanation of
+the direct cause, nor is there a manageably small test case that reliably
+reproduces the problem.
+
+If you encounter any of the following exceptions in B<random places within
+your application stack> - this module may be to blame:
+
+  Operation "ne": no method found,
+    left argument in overloaded package <something>,
+    right argument in overloaded package <something>
+
+or perhaps even
+
+  Stub found while resolving method "???" overloading """" in package <something>
+
+If you fall victim to the above - please attempt to reduce the problem
+to something that could be sent to the L<SQL::Abstract developers
+|DBIx::Class/GETTING_HELP/SUPPORT>
+(either publicly or privately). As a workaround in the meantime you can
+set C<$ENV{SQLA_ISVALUE_IGNORE_AUTOGENERATED_STRINGIFICATION}> to a true
+value, which will most likely eliminate your problem (at the expense of
+not being able to properly detect exotic forms of stringification).
+
+This notice and environment variable will be removed in a future version,
+as soon as the underlying problem is found and a reliable workaround is
+devised.
+
+=back
+
 =head2 is_literal_value
 
 Determines if the supplied argument is a literal value as understood by this
@@ -2632,7 +2683,7 @@ not so common, but perfectly legal Perl). For example, to find a date
 in Postgres you can use something like this:
 
     my %where = (
-       date_column => \[q/= date '2008-09-30' - ?::integer/, 10/]
+       date_column => \[q/= date '2008-09-30' - ?::integer/, 10]
     )
 
 This would create:
@@ -2649,7 +2700,7 @@ L<SQL::Abstract> will simply pass it through intact. So if C<bindtype> is set
 to C<columns> the above example will look like:
 
     my %where = (
-       date_column => \[q/= date '2008-09-30' - ?::integer/, [ dummy => 10 ]/]
+       date_column => \[q/= date '2008-09-30' - ?::integer/, [ dummy => 10 ]]
     )
 
 Literal SQL is especially useful for nesting parenthesized clauses in the