Bug 41950: (follow-up) Add DBIC relationship aliases for +count embeds

Adds DBIC relationship aliases so that +count embeds advertised in
the API specs are backed by actual database relationships, making
them sortable via the SQL COUNT subquery infrastructure.

New aliases:
- Borrower: checkouts (issues)
- Aqbookseller: baskets (aqbaskets), invoices (aqinvoices)
- Ticket: updates (ticket_updates)
- ErmEholdingsPackage: resources (erm_eholdings_resources)
- Biblio: holds (reserves)

Koha methods are updated to use the new relationship names directly,
following the one-liner style: Koha::Foo->_new_from_dbic( scalar ... )

Note: checkouts on Borrower and subscriptions on Aqbookseller already
had matching DBIC relationships. comments on Illrequest, requests on
IllBatch, and items on Biblio also already existed.

Test plan:
1. Apply patch
2. Run:
   $ ktd --shell
   k$ prove t/Koha/REST/Plugin/Query.t \
       t/db_dependent/api/v1/patrons.t \
       t/db_dependent/api/v1/acquisitions_vendors.t \
       t/db_dependent/Koha/REST/Plugin/Objects.t \
       t/db_dependent/Koha/Biblio.t
=> SUCCESS: All tests pass
3. Verify sorting works:
   GET /api/v1/patrons
   x-koha-embed: checkouts+count
   _order_by: -me.checkouts_count
=> SUCCESS: Patrons sorted by checkout count
4. Sign off :-D

Assisted-by: Sonnet 4.6 (Anthropic)
Signed-off-by: Pedro Amorim <pedro.amorim@openfifth.co.uk>

Koha/Acquisition/Bookseller.pm

@@ -46,8 +46,7 @@ Returns the list of baskets for the vendor
 
 sub baskets {
     my ($self) = @_;
-    my $baskets_rs = $self->_result->aqbaskets;
-    return Koha::Acquisition::Baskets->_new_from_dbic($baskets_rs);
+    return Koha::Acquisition::Baskets->_new_from_dbic( scalar $self->_result->baskets );
 }
 
 =head3 contacts
@@ -112,8 +111,7 @@ Returns the list of subscriptions for the vendor
 
 sub subscriptions {
     my ($self) = @_;
-    my $rs = $self->_result->subscriptions;
-    return Koha::Subscriptions->_new_from_dbic($rs);
+    return Koha::Subscriptions->_new_from_dbic( scalar $self->_result->subscriptions );
 }
 
 =head3 aliases
@@ -198,8 +196,7 @@ Returns the list of invoices for the vendor
 
 sub invoices {
     my ($self) = @_;
-    my $invoices_rs = $self->_result->aqinvoices;
-    return Koha::Acquisition::Invoices->_new_from_dbic($invoices_rs);
+    return Koha::Acquisition::Invoices->_new_from_dbic( scalar $self->_result->invoices );
 }
 
 =head3 to_api_mapping

Koha/Biblio.pm

@@ -799,7 +799,7 @@ return the current holds placed on this record
 sub holds {
     my ( $self, $params, $attributes ) = @_;
     $attributes->{order_by} = 'priority' unless exists $attributes->{order_by};
-    my $hold_rs = $self->_result->reserves->search( $params, $attributes );
+    my $hold_rs = $self->_result->holds->search( $params, $attributes );
     return Koha::Holds->_new_from_dbic($hold_rs);
 }
 

Koha/ERM/EHoldings/Package.pm

@@ -67,8 +67,7 @@ Returns the resources from this package
 
 sub resources {
     my ($self) = @_;
-    my $rs = $self->_result->erm_eholdings_resources;
-    return Koha::ERM::EHoldings::Resources->_new_from_dbic($rs);
+    return Koha::ERM::EHoldings::Resources->_new_from_dbic( scalar $self->_result->resources );
 }
 
 =head3 vendor

Koha/ILL/Batch.pm

@@ -87,8 +87,7 @@ Return the I<Koha::ILL::Requests> for this batch
 
 sub requests {
     my ($self) = @_;
-    my $requests = $self->_result->requests;
-    return Koha::ILL::Requests->_new_from_dbic($requests);
+    return Koha::ILL::Requests->_new_from_dbic( scalar $self->_result->requests );
 }
 
 =head3 create_and_log

Koha/Patron.pm

@@ -1728,8 +1728,7 @@ my $checkouts = $patron->checkouts
 
 sub checkouts {
     my ($self) = @_;
-    my $checkouts = $self->_result->issues;
-    return Koha::Checkouts->_new_from_dbic($checkouts);
+    return Koha::Checkouts->_new_from_dbic( scalar $self->_result->checkouts );
 }
 
 =head3 ill_requests

Koha/Schema/Result/Aqbookseller.pm

@@ -627,4 +627,18 @@ sub koha_objects_class {
     'Koha::Acquisition::Booksellers';
 }
 
+__PACKAGE__->has_many(
+  "baskets",
+  "Koha::Schema::Result::Aqbasket",
+  { "foreign.booksellerid" => "self.id" },
+  { cascade_copy => 0, cascade_delete => 0 },
+);
+
+__PACKAGE__->has_many(
+  "invoices",
+  "Koha::Schema::Result::Aqinvoice",
+  { "foreign.booksellerid" => "self.id" },
+  { cascade_copy => 0, cascade_delete => 0 },
+);
+
 1;

Koha/Schema/Result/Biblio.pm

@@ -692,4 +692,11 @@ __PACKAGE__->add_columns(
     "+serial"          => { is_boolean => 1 },
 );
 
+__PACKAGE__->has_many(
+  "holds",
+  "Koha::Schema::Result::Reserve",
+  { "foreign.biblionumber" => "self.biblionumber" },
+  { cascade_copy => 0, cascade_delete => 0 },
+);
+
 1;

Koha/Schema/Result/Borrower.pm

@@ -2311,4 +2311,11 @@ sub koha_object_class {
     'Koha::Patron';
 }
 
+__PACKAGE__->has_many(
+  "checkouts",
+  "Koha::Schema::Result::Issue",
+  { "foreign.borrowernumber" => "self.borrowernumber" },
+  { cascade_copy => 0, cascade_delete => 0 },
+);
+
 1;

Koha/Schema/Result/ErmEholdingsPackage.pm

@@ -253,4 +253,11 @@ sub koha_objects_class {
     'Koha::ERM::EHoldings::Packages';
 }
 
+__PACKAGE__->has_many(
+  "resources",
+  "Koha::Schema::Result::ErmEholdingsResource",
+  { "foreign.package_id" => "self.package_id" },
+  { cascade_copy => 0, cascade_delete => 0 },
+);
+
 1;

Koha/Schema/Result/Ticket.pm

@@ -267,5 +267,11 @@ __PACKAGE__->has_many(
 # DO NOT MODIFY THIS OR ANYTHING ABOVE! md5sum:8bWiSb7hXPFYRzRzrVG3kw
 
 
-# You can replace this text with custom code or comments, and it will be preserved on regeneration
+__PACKAGE__->has_many(
+  "updates",
+  "Koha::Schema::Result::TicketUpdate",
+  { "foreign.ticket_id" => "self.id" },
+  { cascade_copy => 0, cascade_delete => 0 },
+);
+
 1;

Koha/Ticket.pm

@@ -94,9 +94,7 @@ Return any updates attached to this ticket
 
 sub updates {
     my ($self) = @_;
-    my $rs = $self->_result->ticket_updates;
-    return unless $rs;
-    return Koha::Ticket::Updates->_new_from_dbic($rs) if $rs;
+    return Koha::Ticket::Updates->_new_from_dbic( scalar $self->_result->updates );
 }
 
 =head2 Actions

t/Koha/REST/Plugin/Query.t

@@ -209,11 +209,11 @@ get '/dbic_merge_prefetch_count_sorted' => sub {
 
 get '/dbic_merge_prefetch_count_unsortable' => sub {
     my $c          = shift;
-    my $attributes = { order_by => [ { '-desc' => 'me.checkouts_count' } ] };
+    my $attributes = { order_by => [ { '-desc' => 'me.no_dbic_rel_count' } ] };
     my $result_set = Koha::Patrons->new;
 
-    # checkouts is a Koha-only method, not a DBIC relationship
-    $c->stash( 'koha.embed', { "checkouts_count" => { "is_count" => 1 } } );
+    # no_dbic_rel is not a DBIC relationship
+    $c->stash( 'koha.embed', { "no_dbic_rel_count" => { "is_count" => 1 } } );
 
     try {
         $c->dbic_merge_prefetch(
@@ -237,8 +237,8 @@ get '/dbic_merge_prefetch_count_unsortable_display' => sub {
     my $attributes = {};
     my $result_set = Koha::Patrons->new;
 
-    # checkouts is a Koha-only method — no order_by, so no error
-    $c->stash( 'koha.embed', { "checkouts_count" => { "is_count" => 1 } } );
+    # no_dbic_rel is not a DBIC relationship — no order_by, so no error
+    $c->stash( 'koha.embed', { "no_dbic_rel_count" => { "is_count" => 1 } } );
 
     $c->dbic_merge_prefetch(
         {
@@ -281,13 +281,13 @@ get '/dbic_merge_prefetch_nested_count' => sub {
 
 get '/dbic_merge_prefetch_nested_count_unsortable' => sub {
     my $c          = shift;
-    my $attributes = { order_by => [ { '-desc' => 'guarantee.checkouts_count' } ] };
+    my $attributes = { order_by => [ { '-desc' => 'guarantee.no_dbic_rel_count' } ] };
     my $result_set = Koha::Patron::Relationship->new;
 
-    # checkouts is NOT in Patron's prefetch_whitelist
+    # no_dbic_rel is NOT in Patron's prefetch_whitelist
     $c->stash(
         'koha.embed',
-        { "guarantee" => { "children" => { "checkouts_count" => { "is_count" => 1 } } } }
+        { "guarantee" => { "children" => { "no_dbic_rel_count" => { "is_count" => 1 } } } }
     );
 
     try {
@@ -628,7 +628,7 @@ subtest '/dbic_merge_prefetch' => sub {
     $t->get_ok('/dbic_merge_prefetch_count_unsortable')
         ->status_is(400)
         ->json_is( '/error_code' => 'bad_parameter' )
-        ->json_like( '/error' => qr/Cannot sort on checkouts_count/ );
+        ->json_like( '/error' => qr/Cannot sort on no_dbic_rel_count/ );
 
     # Top-level unsortable +count without order_by: no error (display-only fallback)
     $t->get_ok('/dbic_merge_prefetch_count_unsortable_display')
@@ -647,7 +647,7 @@ subtest '/dbic_merge_prefetch' => sub {
     $t->get_ok('/dbic_merge_prefetch_nested_count_unsortable')
         ->status_is(400)
         ->json_is( '/error_code' => 'bad_parameter' )
-        ->json_like( '/error' => qr/Cannot sort on guarantee\.checkouts_count/ );
+        ->json_like( '/error' => qr/Cannot sort on guarantee\.no_dbic_rel_count/ );
 };
 
 subtest '/merge_q_params' => sub {