made search_rs smarter about when to preserve the cache to fix mm prefetch usage

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

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index 9da6a14..c2b045c 100644 (file)
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -11,6 +11,7 @@ use Data::Page;
 use Storable;
 use DBIx::Class::ResultSetColumn;
 use DBIx::Class::ResultSourceHandle;
+use List::Util ();
 use base qw/DBIx::Class/;
 
 __PACKAGE__->mk_group_accessors('simple' => qw/result_class _source_handle/);
@@ -95,6 +96,8 @@ sub new {
 
   $attrs->{alias} ||= 'me';
 
+  # Creation of {} and bless separated to mitigate RH perl bug
+  # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
   my $self = {
     _source_handle => $source,
     result_class => $attrs->{result_class} || $source->resolve->result_class,
@@ -138,6 +141,8 @@ L</ATTRIBUTES>. For more examples of using this function, see
 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
 documentation for the first argument, see L<SQL::Abstract>.
 
+For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
+
 =cut
 
 sub search {
@@ -164,18 +169,26 @@ always return a resultset, even in list context.
 sub search_rs {
   my $self = shift;
 
-  my $rows;
-
-  unless (@_) {                 # no search, effectively just a clone
-    $rows = $self->get_cache;
-  }
-
   my $attrs = {};
   $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
   my $our_attrs = { %{$self->{attrs}} };
   my $having = delete $our_attrs->{having};
   my $where = delete $our_attrs->{where};
 
+  my $rows;
+
+  my %safe = (alias => 1, cache => 1);
+
+  unless (
+    (@_ && defined($_[0])) # @_ == () or (undef)
+    || 
+    (keys %$attrs # empty attrs or only 'safe' attrs
+    && List::Util::first { !$safe{$_} } keys %$attrs)
+  ) {
+    # no search, effectively just a clone
+    $rows = $self->get_cache;
+  }
+
   my $new_attrs = { %{$our_attrs}, %{$attrs} };
 
   # merge new attrs into inherited
@@ -264,6 +277,13 @@ sub search_rs {
 Pass a literal chunk of SQL to be added to the conditional part of the
 resultset query.
 
+CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
+only be used in that context. There are known problems using C<search_literal>
+in chained queries; it can result in bind values in the wrong order.  See
+L<DBIx::Class::Manual::Cookbook/Searching> and
+L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
+require C<search_literal>.
+
 =cut
 
 sub search_literal {
@@ -918,7 +938,7 @@ Performs an SQL C<COUNT> with the same query as the resultset was built
 with to find the number of elements. If passed arguments, does a search
 on the resultset and counts the results of that.
 
-Note: When using C<count> with C<group_by>, L<DBIX::Class> emulates C<GROUP BY>
+Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
 not support C<DISTINCT> with multiple columns. If you are using such a
 database, you should only use columns from the main table in your C<group_by>
@@ -1449,6 +1469,9 @@ sub new_result {
 
   my $alias = $self->{attrs}{alias};
   my $collapsed_cond = $self->{cond} ? $self->_collapse_cond($self->{cond}) : {};
+
+  # precendence must be given to passed values over values inherited from the cond, 
+  # so the order here is important.
   my %new = (
     %{ $self->_remove_alias($collapsed_cond, $alias) },
     %{ $self->_remove_alias($values, $alias) },
@@ -1549,7 +1572,7 @@ sub find_or_new {
 
 =item Arguments: \%vals
 
-=item Return Value: $object
+=item Return Value: a L<DBIx::Class::Row> $object
 
 =back
 
@@ -2064,10 +2087,10 @@ sub _merge_attr {
       $position++;
     }
     my ($b_key) = ( ref $b_element eq 'HASH' ) ? keys %{$b_element} : ($b_element);
+
     if ($best_candidate->{score} == 0 || exists $seen_keys->{$b_key}) {
       push( @{$a}, $b_element );
     } else {
-      $seen_keys->{$b_key} = 1; # don't merge the same key twice
       my $a_best = $a->[$best_candidate->{position}];
       # merge a_best and b_element together and replace original with merged
       if (ref $a_best ne 'HASH') {
@@ -2077,6 +2100,7 @@ sub _merge_attr {
         $a->[$best_candidate->{position}] = { $key => $self->_merge_attr($a_best->{$key}, $b_element->{$key}) };
       }
     }
+    $seen_keys->{$b_key} = 1; # don't merge the same key twice
   }
 
   return $a;
@@ -2189,7 +2213,7 @@ return a column named C<count(employeeid)> in the above example.
 =over 4
 
 Indicates additional columns to be selected from storage.  Works the same as
-L<select> but adds columns to the selection.
+L</select> but adds columns to the selection.
 
 =back
 
@@ -2197,7 +2221,7 @@ L<select> but adds columns to the selection.
 
 =over 4
 
-Indicates additional column names for those added via L<+select>.
+Indicates additional column names for those added via L</+select>.
 
 =back
 
@@ -2318,6 +2342,8 @@ to Earth' and a cd with title 'Popular'.
 If you want to fetch related objects from other tables as well, see C<prefetch>
 below.
 
+For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
+
 =head2 prefetch
 
 =over 4