From: Brian Phillips <bphillips@cpan.org>
Date: Wed, 11 May 2011 13:28:56 +0000 (-0500)
Subject: take more care in mangling SELECT when applying subquery limits
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=f74d22e2933e0ffed5955df8f35b47a4b096d6ef;p=dbsrgits%2FDBIx-Class-Historic.git

take more care in mangling SELECT when applying subquery limits

Previously, if there was a SELECT sub-query in the WHERE
clause, the regular expression was being a bit too greedy
and stripping too much out.
---

diff --git a/Changes b/Changes
index 0111ffa..cfaacab 100644
--- a/Changes
+++ b/Changes
@@ -1,5 +1,9 @@
 Revision history for DBIx::Class
 
+        - Fix issue where the query was becoming overly mangled when trying
+          to use pagination with a query that has a sub-select in the WHERE
+          clause.
+
 0.08192 2011-05-10 04:20 (UTC)
     * Fixes
         - Fix serious regression on SQLite, corrupting data when an alphanum
diff --git a/lib/DBIx/Class/SQLMaker.pm b/lib/DBIx/Class/SQLMaker.pm
index 66b6c73..c4bd627 100644
--- a/lib/DBIx/Class/SQLMaker.pm
+++ b/lib/DBIx/Class/SQLMaker.pm
@@ -205,7 +205,12 @@ sub select {
       }
     ;
 
-    $sql = $self->$limiter ($sql, $rs_attrs, $limit, $offset);
+    $sql = $self->$limiter (
+      $sql,
+      { %{$rs_attrs||{}}, _selector_sql => $fields },
+      $limit,
+      $offset
+    );
   }
   else {
     ($sql, @bind) = $self->next::method ($table, $fields, $where, $rs_attrs);
diff --git a/lib/DBIx/Class/SQLMaker/LimitDialects.pm b/lib/DBIx/Class/SQLMaker/LimitDialects.pm
index e3da121..f3b815b 100644
--- a/lib/DBIx/Class/SQLMaker/LimitDialects.pm
+++ b/lib/DBIx/Class/SQLMaker/LimitDialects.pm
@@ -623,9 +623,14 @@ sub _subqueried_limit_attrs {
     'Limit dialect implementation usable only in the context of DBIC (missing $rs_attrs)'
   ) unless ref ($rs_attrs) eq 'HASH';
 
-  # mangle the input sql as we will be replacing the selector
-  $proto_sql =~ s/^ \s* SELECT \s+ .+ \s+ (?= \b FROM \b )//ix
-    or $self->throw_exception("Unrecognizable SELECT: $proto_sql");
+  # mangle the input sql as we will be replacing the selector entirely
+  unless (
+    $rs_attrs->{_selector_sql}
+      and
+    $proto_sql =~ s/^ \s* SELECT \s* \Q$rs_attrs->{_selector_sql}//ix
+  ) {
+    $self->throw_exception("Unrecognizable SELECT: $proto_sql");
+  }
 
   my ($re_sep, $re_alias) = map { quotemeta $_ } ( $self->{name_sep}, $rs_attrs->{alias} );
 
diff --git a/t/sqlmaker/limit_dialects/rno.t b/t/sqlmaker/limit_dialects/rno.t
index 00a6523..457cf7d 100644
--- a/t/sqlmaker/limit_dialects/rno.t
+++ b/t/sqlmaker/limit_dialects/rno.t
@@ -180,5 +180,35 @@ is_same_sql_bind(
   );
 }
 
+{
+my $subq = $schema->resultset('Owners')->search({
+   'books.owner' => { -ident => 'owner.id' },
+}, { alias => 'owner', select => ['id'] } )->count_rs;
+
+my $rs_selectas_rel = $schema->resultset('BooksInLibrary')->search( { -exists => $subq->as_query }, { select => ['id','owner'], rows => 1 } );
+
+is_same_sql_bind(
+  $rs_selectas_rel->as_query,
+  '(
+ SELECT [id], [owner] FROM (
+   SELECT [id], [owner], ROW_NUMBER() OVER(  ) AS [rno__row__index] FROM (
+     SELECT [me].[id], [me].[owner]
+     FROM [books] [me]
+     WHERE ( ( (EXISTS (
+       SELECT COUNT( * ) FROM [owners] [owner] WHERE ( [books].[owner] = [owner].[id] )
+     )) AND [source] = ? ) )
+   ) [me]
+ ) [me] WHERE [rno__row__index] >= ? AND [rno__row__index] <= ?
+ )',
+  [
+    [ { sqlt_datatype => 'varchar', sqlt_size => 100, dbic_colname => 'source' } => 'Library' ],
+    [ $OFFSET => 1 ],
+    [ $TOTAL => 1 ],
+  ],
+  'Pagination with sub-query in WHERE works'
+);
+
+}
+
 
 done_testing;
diff --git a/t/sqlmaker/limit_dialects/rownum.t b/t/sqlmaker/limit_dialects/rownum.t
index f263166..d9bc1a4 100644
--- a/t/sqlmaker/limit_dialects/rownum.t
+++ b/t/sqlmaker/limit_dialects/rownum.t
@@ -125,5 +125,29 @@ is_same_sql_bind(
   );
 }
 
+{
+my $subq = $s->resultset('Owners')->search({
+   'books.owner' => { -ident => 'owner.id' },
+}, { alias => 'owner', select => ['id'] } )->count_rs;
+
+my $rs_selectas_rel = $s->resultset('BooksInLibrary')->search( { -exists => $subq->as_query }, { select => ['id','owner'], rows => 1 } );
+
+is_same_sql_bind(
+  $rs_selectas_rel->as_query,
+  '(  SELECT id, owner FROM (
+     SELECT me.id, me.owner
+     FROM books me
+     WHERE ( ( (EXISTS (SELECT COUNT( * ) FROM owners owner WHERE ( books.owner = owner.id ))) AND source = ? ) )
+   ) me WHERE ROWNUM <= ?
+ )',
+  [
+    [ { sqlt_datatype => 'varchar', sqlt_size => 100, dbic_colname => 'source' } => 'Library' ],
+    [ $TOTAL => 1 ],
+  ],
+  'Pagination with sub-query in WHERE works'
+);
+
+}
+
 
 done_testing;
diff --git a/t/sqlmaker/limit_dialects/toplimit.t b/t/sqlmaker/limit_dialects/toplimit.t
index fc1c7fb..bb9ef9a 100644
--- a/t/sqlmaker/limit_dialects/toplimit.t
+++ b/t/sqlmaker/limit_dialects/toplimit.t
@@ -253,4 +253,22 @@ is_same_sql_bind( $rs_selectas_top->search({})->as_query,
   );
 }
 
+{
+my $subq = $schema->resultset('Owners')->search({
+   'books.owner' => { -ident => 'owner.id' },
+}, { alias => 'owner', select => ['id'] } )->count_rs;
+
+my $rs_selectas_rel = $schema->resultset('BooksInLibrary')->search( { -exists => $subq->as_query }, { select => ['id','owner'], rows => 1 } );
+
+is_same_sql_bind(
+  $rs_selectas_rel->as_query,
+  '(SELECT TOP 1 me.id, me.owner  FROM books me WHERE ( ( (EXISTS (SELECT COUNT( * ) FROM owners owner WHERE ( books.owner = owner.id ))) AND source = ? ) )   ORDER BY me.id)',
+  [
+    [ { sqlt_datatype => 'varchar', sqlt_size => 100, dbic_colname => 'source' } => 'Library' ],
+  ],
+  'Pagination with sub-query in WHERE works'
+);
+
+}
+
 done_testing;