Bug 11338: prevent deletion of items that are captured for holds

In C4::Items::DelItemCheck, there are two SQL queries: one to check
if item is on loan, the other if item is reserved.

Those two queries use "SELECT * FROM table", fetch the data with
"$var = $sth->fetchrow", and use "$var" as a boolean condition.

This is not correct, SQL query should be "SELECT COUNT(*) FROM table".

As a consequence, it was possible to delete an item without warning to
the operator even if it was waiting on the hold shelf or in transit to
fill a hold.

This patch corrects the SQL queries and sets my ($var) to show that
fetchrow returns an array.

Test plan :
- Set an item A onloan
- Set an item B reserved and the reserve waiting
- Go to items cataloguing : cgi-bin/koha/cataloguing/additem.pl?biblionumber=XXX
- Try to delete item A
=> You get an alert and item is not deleted
- Try to delete item B
=> You get an alert and item is not deleted

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>

Works, and has the added bonus of being a tiny bit faster.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Passes t, xt and QA script tests.
Also tried deleting via batch delete - correct warnings are displayed.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>

C4/Items.pm

@@ -2253,11 +2253,14 @@ sub DelItemCheck {
 
 
     # check that there is no issue on this item before deletion.
-    my $sth=$dbh->prepare("select * from issues i where i.itemnumber=?");
+    my $sth = $dbh->prepare(q{
+        SELECT COUNT(*) FROM issues
+        WHERE itemnumber = ?
+    });
     $sth->execute($itemnumber);
+    my ($onloan) = $sth->fetchrow;
 
     my $item = GetItem($itemnumber);
-    my $onloan=$sth->fetchrow;
 
     if ($onloan){
         $error = "book_on_loan" 
@@ -2270,9 +2273,13 @@ sub DelItemCheck {
     }
 	else{
         # check it doesnt have a waiting reserve
-        $sth=$dbh->prepare("SELECT * FROM reserves WHERE (found = 'W' or found = 'T') AND itemnumber = ?");
+        $sth = $dbh->prepare(q{
+            SELECT COUNT(*) FROM reserves
+            WHERE (found = 'W' OR found = 'T')
+            AND itemnumber = ?
+        });
         $sth->execute($itemnumber);
-        my $reserve=$sth->fetchrow;
+        my ($reserve) = $sth->fetchrow;
         if ($reserve){
             $error = "book_reserved";
         } elsif ($countanalytics > 0){