Fix shared tables tenant index

src/Database/Trait/Attributes.php

@@ -378,6 +378,17 @@ public function deleteAttribute(string $collection, string $key): void
 
         $deletedInSchema = $this->deleteAttributeFromSchema($definition->getId(), $key);
 
+        // An engine drops an index with its column only when no other column is left in it, and under
+        // shared tables every index also holds the tenant column. An index whose last attribute this was
+        // would survive on the tenant column alone and refuse the next index created under its name.
+        if ($this->adapter->hasSharedTables()) {
+            foreach ($indexes as $index) {
+                if ($index->attributes === [$key]) {
+                    $this->deleteIndexFromSchema($definition->getId(), $index->key);
+                }
+            }
+        }
+
         $this->updateMetadata(
             collection: $definition,
             rollbackOperation: fn () => $this->adapter->createAttribute($definition->getId(), $attribute),

tests/e2e/Adapter/Scopes/SchemaReconciliationTests.php

@@ -4,6 +4,8 @@
 
 use Throwable;
 use Utopia\Database\Adapter\Feature;
+use Utopia\Database\Adapter\Mongo;
+use Utopia\Database\Adapter\Postgres;
 use Utopia\Database\Attribute;
 use Utopia\Database\Capability;
 use Utopia\Database\Collection;
@@ -230,6 +232,43 @@ public function testAnOrphanIndexOfTheRequestedDefinitionIsReused(): void
         }
     }
 
+    public function testDeletingAnAttributeDropsItsOnlyIndexFromTheSchema(): void
+    {
+        $database = $this->getDatabase();
+        $adapter = $database->getAdapter();
+
+        // Mongo unsets the field and keeps its indexes.
+        if (! $adapter->supports(Capability::SchemaIntrospection) || $adapter instanceof Mongo) {
+            $this->expectNotToPerformAssertions();
+
+            return;
+        }
+
+        $collection = 'reconcileDroppedAttributeIndex';
+        $this->createReconciledCollection($database, $collection, [
+            Attribute::string(key: 'status', size: 255),
+            Attribute::string(key: 'name', size: 255),
+        ]);
+
+        try {
+            $database->createIndex($collection, Index::key(key: 'status_index', attributes: ['status']));
+            $database->createIndex($collection, Index::key(key: 'status_name', attributes: ['status', 'name']));
+
+            $database->deleteAttribute($collection, 'status');
+
+            $this->assertFalse($this->hasSchemaIndex($database, $collection, 'status_index'));
+            // Postgres drops every index on a dropped column, composite ones included.
+            if (! $adapter instanceof Postgres) {
+                $this->assertTrue($this->hasSchemaIndex($database, $collection, 'status_name'));
+            }
+
+            $database->createAttribute($collection, Attribute::string(key: 'status', size: 255));
+            $this->assertSame('status_index', $database->createIndex($collection, Index::key(key: 'status_index', attributes: ['status']))->key);
+        } finally {
+            $database->deleteCollection($collection);
+        }
+    }
+
     /**
      * @param  list<Attribute>  $attributes
      */