fix(badge-scans): disambiguate colliding extra question columns in the badge scans CSV export

app/ModelSerializers/Summit/Registration/SponsorBadgeScanCSVSerializer.php

@@ -52,6 +52,31 @@ private static function isAllowedExtraQuestion(array $allowed_extra_questions, i
         return false;
     }
 
+    /**
+     * Returns a CSV column key that does not collide with the already taken ones,
+     * disambiguating with the question name, then the id, then a counter as last resort.
+     * @param array $taken_keys
+     * @param string $label
+     * @param string $name
+     * @param int $id
+     * @return string
+     */
+    private static function getUniqueColumnKey(array $taken_keys, string $label, string $name, int $id): string
+    {
+        if (!array_key_exists($label, $taken_keys)) return $label;
+
+        $key = sprintf("%s (%s)", $label, AbstractSerializer::getCSVLabel($name));
+        if (!array_key_exists($key, $taken_keys)) return $key;
+
+        $key = sprintf("%s (%s-%s)", $label, AbstractSerializer::getCSVLabel($name), $id);
+        $base = $key;
+        $i = 2;
+        while (array_key_exists($key, $taken_keys)) {
+            $key = sprintf("%s-%s", $base, $i++);
+        }
+        return $key;
+    }
+
     /**
      * @param null $expand
      * @param array $fields
@@ -93,7 +118,13 @@ public function serialize($expand = null, array $fields = array(), array $relati
 
                 if (!self::isAllowedExtraQuestion($allowed_sponsor_extra_questions, $question->getId())) continue;
 
-                $label = AbstractSerializer::getCSVLabel($question->getLabel());
+                $label = self::getUniqueColumnKey
+                (
+                    $values + $sponsor_questions_values,
+                    AbstractSerializer::getCSVLabel($question->getLabel()),
+                    $question->getName(),
+                    $question->getId()
+                );
                 Log::debug
                 (
                     sprintf
@@ -130,9 +161,15 @@ public function serialize($expand = null, array $fields = array(), array $relati
             foreach ($params['ticket_questions'] as $question) {
                 if (!self::isAllowedExtraQuestion($allowed_attendee_extra_questions, $question->getId())) continue;
 
-                $label = AbstractSerializer::getCSVLabel($question->getLabel());
-
                 if (!$question instanceof SummitOrderExtraQuestionType) continue;
+
+                $label = self::getUniqueColumnKey
+                (
+                    $values + $sponsor_questions_values + $ticket_questions_values,
+                    AbstractSerializer::getCSVLabel($question->getLabel()),
+                    $question->getName(),
+                    $question->getId()
+                );
                 $ticket_questions_values[$label] = '';
 
                 if (!is_null($ticket_owner)) {

tests/SponsorBadgeScanCSVSerializerTest.php

@@ -0,0 +1,48 @@
+<?php namespace Tests;
+/*
+ * Copyright 2026 OpenStack Foundation
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+use App\ModelSerializers\Summit\SponsorBadgeScanCSVSerializer;
+use ReflectionMethod;
+
+final class SponsorBadgeScanCSVSerializerTest extends TestCase
+{
+    private function uniqueKey(array $taken, string $label, string $name, int $id): string
+    {
+        $method = new ReflectionMethod(SponsorBadgeScanCSVSerializer::class, 'getUniqueColumnKey');
+        $method->setAccessible(true);
+        return $method->invoke(null, $taken, $label, $name, $id);
+    }
+
+    public function testNoCollisionKeepsLabel(): void
+    {
+        $this->assertSame('company size', $this->uniqueKey(['notes' => 'x'], 'company size', 'COMPANY_SIZE', 1));
+    }
+
+    public function testCollisionWithFixedColumnUsesQuestionName(): void
+    {
+        $this->assertSame('notes (notes_q)', $this->uniqueKey(['notes' => 'scan notes'], 'notes', 'NOTES_Q', 10));
+    }
+
+    public function testCollisionWithSameLabelAndNameUsesQuestionId(): void
+    {
+        $taken = ['notes' => 'a', 'notes (notes_q)' => 'b'];
+        $this->assertSame('notes (notes_q-11)', $this->uniqueKey($taken, 'notes', 'notes_q', 11));
+    }
+
+    public function testCollisionWithIdKeyUsesCounter(): void
+    {
+        $taken = ['notes' => 'a', 'notes (notes_q)' => 'b', 'notes (notes_q-11)' => 'c'];
+        $this->assertSame('notes (notes_q-11)-2', $this->uniqueKey($taken, 'notes', 'notes_q', 11));
+    }
+}