Bug 41229: Fix desk and register session persistence on library change

When changing library in circ/set-library.pl, desk and register values
were not being properly cleared from the session. This caused stale
desk/register data from the previous library to persist, resulting in:
- Incorrect cashup displays showing wrong library's register
- POS defaulting to registers from different libraries
- Session state inconsistent with visual UI

Three issues fixed:
1. Template: Changed register "None" option ID from "set-library-noregister"
   to "noregister" to match JavaScript expectations (consistent with desk handling)
2. Desk logic: Changed condition to use defined() and explicitly clear session
   when "No desk" is selected
3. Register logic: Added session clearing when "No register" is selected and
   fixed condition to handle empty initial state

Test plan:
1. Select Library A with Register 5
2. Change to Library B without selecting a register
3. Verify register is cleared from session (check POS page)
4. Repeat for desk selection
5. Verify explicit "-- None --" selection clears session values

Signed-off-by: Jason Robb <jrobb@sekls.org>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>

circ/set-library.pl

@@ -71,26 +71,37 @@ if (
     $branch = $userenv_branch;                           # fallback value
 }
 
-if ( $desk_id && ( !$userenv_desk or $userenv_desk ne $desk_id ) ) {
+if ( defined($desk_id) && ( !$userenv_desk || $userenv_desk ne $desk_id ) ) {
-    my $desk          = Koha::Desks->find( { desk_id => $desk_id } );
+    if ($desk_id) {
-    my $old_desk_name = '';
+
-    if ($userenv_desk) {
+        # A desk was selected
-        $old_desk_name = Koha::Desks->find( { desk_id => $userenv_desk } )->desk_name;
+        my $desk = Koha::Desks->find( { desk_id => $desk_id } );
+        $session->param( desk_name => $desk->desk_name );
+        $session->param( desk_id   => $desk->desk_id );
+    } else {
+
+        # "No desk" was explicitly selected - clear desk from session
+        $session->clear( [ 'desk_name', 'desk_id' ] );
     }
-    $session->param( desk_name => $desk->desk_name );
-    $session->param( desk_id   => $desk->desk_id );
     $updated = 1;
 } else {
     $desk_id = $userenv_desk;
 }
 
 if ( defined($register_id)
-    && ( $userenv_register_id ne $register_id ) )
+    && ( !$userenv_register_id || $userenv_register_id ne $register_id ) )
 {
-    my $old_register_name = C4::Context->userenv->{'register_name'} || '';
+    if ($register_id) {
-    my $register          = Koha::Cash::Registers->find($register_id);
+
-    $session->param( 'register_id',   $register_id );
+        # A register was selected
-    $session->param( 'register_name', $register ? $register->name : '' );
+        my $register = Koha::Cash::Registers->find($register_id);
+        $session->param( 'register_id',   $register_id );
+        $session->param( 'register_name', $register ? $register->name : '' );
+    } else {
+
+        # "No register" was explicitly selected - clear register from session
+        $session->clear( [ 'register_id', 'register_name' ] );
+    }
     $updated = 1;
 } else {
     $register_id = $userenv_register_id;

koha-tmpl/intranet-tmpl/prog/en/modules/circ/set-library.tt

@@ -87,7 +87,7 @@
                     <li>
                         <label for="set-library-register_id">Choose cash register:</label>
                         <select name="register_id" id="set-library-register_id">
-                            <option id="set-library-noregister" selected="selected" value="">-- None --</option>
+                            <option id="noregister" selected="selected" value="">-- None --</option>
                             [% PROCESS options_for_registers registers => Registers.all() %]
                         </select>
                     </li>