From a4a60be9c7e810d1e0d2ce0b7d4c8bba6ac89afc Mon Sep 17 00:00:00 2001
From: Jan-Hendrik Willms <tleilax+studip@gmail.com>
Date: Fri, 27 Feb 2026 15:59:30 +0100
Subject: fix migration mess, fixes #6255

Closes #6255

Merge request studip/studip!4729
---
 ...nique_constraint_to_forum_posting_reactions.php | 47 ++++++++++++++++++++++
 ...nique_constraint_to_forum_posting_reactions.php | 30 ++++----------
 2 files changed, 54 insertions(+), 23 deletions(-)
 create mode 100644 db/migrations/6.1.19_add_unique_constraint_to_forum_posting_reactions.php

diff --git a/db/migrations/6.1.19_add_unique_constraint_to_forum_posting_reactions.php b/db/migrations/6.1.19_add_unique_constraint_to_forum_posting_reactions.php
new file mode 100644
index 0000000..37c947a
--- /dev/null
+++ b/db/migrations/6.1.19_add_unique_constraint_to_forum_posting_reactions.php
@@ -0,0 +1,47 @@
+<?php
+final class AddUniqueConstraintToForumPostingReactions extends Migration
+{
+    protected function up()
+    {
+        // remove duplicate reactions
+        DBManager::get()->exec("
+            DELETE t1
+            FROM forum_posting_reactions AS t1
+            JOIN forum_posting_reactions AS t2
+              ON t1.posting_id = t2.posting_id
+                AND t1.user_id   = t2.user_id
+                AND t1.emoji     = t2.emoji
+                AND t1.id        > t2.id;
+        ");
+
+        // Migration was once defined as 6.2.2 thus we need to check if the
+        // constraint already exists and cleanup table schema_version.
+
+        if (!$this->hasConstraint()) {
+            DBManager::get()->exec(
+                "ALTER TABLE forum_posting_reactions ADD CONSTRAINT unique_posting_user_emoji UNIQUE (posting_id, user_id, emoji)"
+            );
+        }
+
+        if (!file_exists(__DIR__ . '/6.2.1_add_booking_text_to_resource_requests.php')) {
+            $query = "DELETE FROM schema_version
+                      WHERE `domain` = 'studip'
+                        AND `branch` = '6.2'
+                        AND `version` = '2';";
+            DBManager::get()->exec($query);
+        }
+    }
+
+    protected function down()
+    {
+        DBManager::get()->exec("ALTER TABLE forum_posting_reactions DROP INDEX unique_posting_user_emoji");
+    }
+
+    private function hasConstraint(): bool
+    {
+        $query = "SHOW INDEX
+                  FROM forum_posting_reactions
+                  WHERE Key_name = 'unique_posting_user_emoji'";
+        return (bool) DBManager::get()->fetchColumn($query);
+    }
+}
diff --git a/db/migrations/6.2.2_add_unique_constraint_to_forum_posting_reactions.php b/db/migrations/6.2.2_add_unique_constraint_to_forum_posting_reactions.php
index 4a73a9f..f867abd 100644
--- a/db/migrations/6.2.2_add_unique_constraint_to_forum_posting_reactions.php
+++ b/db/migrations/6.2.2_add_unique_constraint_to_forum_posting_reactions.php
@@ -1,27 +1,11 @@
 <?php
-
-final class AddUniqueConstraintToForumPostingReactions extends Migration
+/**
+ * @see https://gitlab.studip.de/studip/studip/-/issues/6255
+ */
+return new class extends Migration
 {
-    protected function up()
+    public function description()
     {
-        // remove duplicate reactions
-        DBManager::get()->exec("
-            DELETE t1
-            FROM forum_posting_reactions AS t1
-            JOIN forum_posting_reactions AS t2
-              ON t1.posting_id = t2.posting_id
-                AND t1.user_id   = t2.user_id
-                AND t1.emoji     = t2.emoji
-                AND t1.id        > t2.id;
-        ");
-
-        DBManager::get()->exec(
-            "ALTER TABLE forum_posting_reactions ADD CONSTRAINT unique_posting_user_emoji UNIQUE (posting_id, user_id, emoji)"
-        );
+        return 'Dummy migration that does nothing';
     }
-
-    protected function down()
-    {
-        DBManager::get()->exec("ALTER TABLE forum_posting_reactions DROP INDEX unique_posting_user_emoji");
-    }
-}
+};
-- 
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