Fix null path confirmation rows

services/nginx/app/modules/selfserve/classes/selfserve_studio_graph.php

@@ -4319,8 +4319,10 @@ class selfserve_studio_graph
         int $terminalPathCount,
         array $questionIds,
         array $progress = [],
-        array $confirmationRows = []
+        ?array $confirmationRows = null
     ): array {
+        $confirmationRows = $confirmationRows ?? [];
+
         usort($outcomes, static fn(array $left, array $right): int => ((int)($right['path_count'] ?? 0) <=> (int)($left['path_count'] ?? 0))
             ?: strcmp((string)($left['summary'] ?? ''), (string)($right['summary'] ?? '')));
         foreach ($outcomes as $index => &$outcome) {

services/nginx/app/tests/Unit/Selfserve/SelfserveStudioGraphTest.php

@@ -1265,6 +1265,29 @@ it('marks projected path confirmations confirmed or stale by stable signatures',
         ->and($changed['summary']['confirmations']['stale'])->toBe(1);
 });
 
+it('treats null path confirmation rows as an empty confirmation set', function (): void {
+    $service = selfserve_studio_graph_without_constructor();
+    $method = new ReflectionMethod(selfserve_studio_graph::class, 'pathOutcomesPayload');
+
+    $payload = $method->invoke(
+        $service,
+        ['department_id' => 6, 'lane_id' => 7],
+        [],
+        [],
+        [],
+        false,
+        null,
+        0,
+        0,
+        [],
+        [],
+        null
+    );
+
+    expect($payload['summary']['confirmations']['total'])->toBe(0)
+        ->and($payload['confirmations']['removed'])->toBe([]);
+});
+
 it('truncates path outcome projection when the state cap is reached', function (): void {
     $service = selfserve_studio_graph_without_constructor();
     $simulate = function (array $overrides): array {