fix: skip orphan reconciliation for shared tables in createCollection

src/Database/Adapter/Mongo.php

@@ -414,8 +414,10 @@ public function createCollection(string $name, array $attributes = [], array $in
     {
         $id = $this->getNamespace() . '_' . $this->filter($name);
 
-        // For metadata collections outside transactions, check if exists first
-        if (!$this->inTransaction && $name === Database::METADATA && $this->exists($this->getNamespace(), $name)) {
+        // In shared-tables mode or for metadata, the physical collection may
+        // already exist for another tenant. Return early to avoid a
+        // "Collection Exists" exception from the client.
+        if (!$this->inTransaction && ($this->getSharedTables() || $name === Database::METADATA) && $this->exists($this->getNamespace(), $name)) {
             return true;
         }
 

src/Database/Adapter/Postgres.php

@@ -439,7 +439,11 @@ public function deleteCollection(string $id): bool
         $sql = "DROP TABLE {$this->getSQLTable($id)}, {$this->getSQLTable($id . '_perms')}";
         $sql = $this->trigger(Database::EVENT_COLLECTION_DELETE, $sql);
 
-        return $this->getPDO()->prepare($sql)->execute();
+        try {
+            return $this->getPDO()->prepare($sql)->execute();
+        } catch (PDOException $e) {
+            throw $this->processException($e);
+        }
     }
 
     /**
@@ -2229,6 +2233,11 @@ protected function processException(PDOException $e): \Exception
             return new LimitException('Datetime field overflow', $e->getCode(), $e);
         }
 
+        // Unknown table
+        if ($e->getCode() === '42P01' && isset($e->errorInfo[1]) && $e->errorInfo[1] === 7) {
+            return new NotFoundException('Collection not found', $e->getCode(), $e);
+        }
+
         // Unknown column
         if ($e->getCode() === "42703" && isset($e->errorInfo[1]) && $e->errorInfo[1] === 7) {
             return new NotFoundException('Attribute not found', $e->getCode(), $e);

src/Database/Database.php

@@ -1793,16 +1793,27 @@ public function createCollection(string $id, array $attributes = [], array $inde
         try {
             $this->adapter->createCollection($id, $attributes, $indexes);
         } catch (DuplicateException $e) {
-            // Metadata check (above) already verified collection is absent
-            // from metadata. A DuplicateException from the adapter means the
-            // collection exists only in physical schema — an orphan from a prior
-            // partial failure. Drop and recreate to ensure schema matches.
-            try {
-                $this->adapter->deleteCollection($id);
-            } catch (NotFoundException) {
-                // Already removed by a concurrent reconciler.
+            if ($this->adapter->getSharedTables()) {
+                // In shared-tables mode the physical table is reused across
+                // tenants. A DuplicateException simply means the table already
+                // exists for another tenant — not an orphan. Verify the table
+                // is actually present before writing tenant metadata.
+                if ($id !== self::METADATA && !$this->adapter->exists($this->adapter->getDatabase(), $id)) {
+                    throw $e;
+                }
+            } else {
+                // Metadata check (above) already verified collection is absent
+                // from metadata. A DuplicateException from the adapter means
+                // the collection exists only in physical schema — an orphan
+                // from a prior partial failure. Drop and recreate to ensure
+                // schema matches.
+                try {
+                    $this->adapter->deleteCollection($id);
+                } catch (NotFoundException) {
+                    // Already removed by a concurrent reconciler.
+                }
+                $this->adapter->createCollection($id, $attributes, $indexes);
             }
-            $this->adapter->createCollection($id, $attributes, $indexes);
         }
 
         if ($id === self::METADATA) {
@@ -1812,10 +1823,14 @@ public function createCollection(string $id, array $attributes = [], array $inde
         try {
             $createdCollection = $this->silent(fn () => $this->createDocument(self::METADATA, $collection));
         } catch (\Throwable $e) {
-            try {
-                $this->cleanupCollection($id);
-            } catch (\Throwable $e) {
-                Console::error("Failed to rollback collection '{$id}': " . $e->getMessage());
+            if (!$this->adapter->getSharedTables()) {
+                try {
+                    $this->cleanupCollection($id);
+                } catch (\Throwable $e) {
+                    Console::error("Failed to rollback collection '{$id}': " . $e->getMessage());
+                }
+            } else {
+                Console::warning("createCollection '{$id}' metadata failed in shared-tables mode; physical table retained. Metadata document must be re-created.");
             }
             throw new DatabaseException("Failed to create collection metadata for '{$id}': " . $e->getMessage(), previous: $e);
         }

tests/e2e/Adapter/Scopes/CollectionTests.php

@@ -1326,6 +1326,138 @@ public function testSharedTablesDuplicates(): void
             ->setDatabase($schema);
     }
 
+    public function testSharedTablesMultiTenantCreateCollection(): void
+    {
+        /** @var Database $database */
+        $database = $this->getDatabase();
+        $sharedTables = $database->getSharedTables();
+        $namespace = $database->getNamespace();
+        $schema = $database->getDatabase();
+        $originalTenant = $database->getTenant();
+        $createdDb = false;
+
+        if ($sharedTables) {
+            // Already in shared-tables mode (SharedTables/* test classes)
+        } elseif ($database->getAdapter()->getSupportForSchemas()) {
+            $dbName = 'stMultiTenant';
+            if ($database->exists($dbName)) {
+                $database->setDatabase($dbName)->delete();
+            }
+            $database
+                ->setDatabase($dbName)
+                ->setNamespace('')
+                ->setSharedTables(true)
+                ->setTenant(10)
+                ->create();
+            $createdDb = true;
+        } else {
+            $this->expectNotToPerformAssertions();
+            return;
+        }
+
+        $tenant1 = $database->getAdapter()->getIdAttributeType() === Database::VAR_INTEGER ? 10 : 'tenant_10';
+        $tenant2 = $database->getAdapter()->getIdAttributeType() === Database::VAR_INTEGER ? 20 : 'tenant_20';
+        $colName = 'multiTenantCol';
+
+        $database->setTenant($tenant1);
+
+        $database->createCollection($colName, [
+            new Document([
+                '$id' => 'name',
+                'type' => Database::VAR_STRING,
+                'size' => 128,
+                'required' => true,
+            ]),
+        ]);
+
+        $col1 = $database->getCollection($colName);
+        $this->assertFalse($col1->isEmpty());
+        $this->assertEquals(1, \count($col1->getAttribute('attributes')));
+
+        $database->setTenant($tenant2);
+
+        $database->createCollection($colName, [
+            new Document([
+                '$id' => 'name',
+                'type' => Database::VAR_STRING,
+                'size' => 128,
+                'required' => true,
+            ]),
+        ]);
+
+        $col2 = $database->getCollection($colName);
+        $this->assertFalse($col2->isEmpty());
+        $this->assertEquals(1, \count($col2->getAttribute('attributes')));
+
+        $database->setTenant($tenant1);
+        $col1Again = $database->getCollection($colName);
+        $this->assertFalse($col1Again->isEmpty());
+
+        if ($createdDb) {
+            $database->delete();
+        } else {
+            $database->setTenant($tenant1);
+            $database->deleteCollection($colName);
+            $database->setTenant($tenant2);
+            $database->deleteCollection($colName);
+        }
+
+        $database
+            ->setSharedTables($sharedTables)
+            ->setNamespace($namespace)
+            ->setDatabase($schema)
+            ->setTenant($originalTenant);
+    }
+
+    public function testSharedTablesMultiTenantCreate(): void
+    {
+        /** @var Database $database */
+        $database = $this->getDatabase();
+        $sharedTables = $database->getSharedTables();
+        $namespace = $database->getNamespace();
+        $schema = $database->getDatabase();
+        $originalTenant = $database->getTenant();
+        $createdDb = false;
+
+        $tenant1 = $database->getAdapter()->getIdAttributeType() === Database::VAR_INTEGER ? 100 : 'tenant_100';
+        $tenant2 = $database->getAdapter()->getIdAttributeType() === Database::VAR_INTEGER ? 200 : 'tenant_200';
+
+        if ($sharedTables) {
+            // Already in shared-tables mode; create() should be idempotent
+            $database->setTenant($tenant1);
+            $database->create();
+            $database->setTenant($tenant2);
+            $database->create();
+            $this->assertTrue($database->exists());
+        } elseif ($database->getAdapter()->getSupportForSchemas()) {
+            $dbName = 'stMultiCreate';
+            if ($database->exists($dbName)) {
+                $database->setDatabase($dbName)->delete();
+            }
+            $database
+                ->setDatabase($dbName)
+                ->setNamespace('')
+                ->setSharedTables(true)
+                ->setTenant($tenant1)
+                ->create();
+            $this->assertTrue($database->exists($dbName));
+            $database->setTenant($tenant2);
+            $database->create();
+            $this->assertTrue($database->exists($dbName));
+            $database->delete();
+            $createdDb = true;
+        } else {
+            $this->expectNotToPerformAssertions();
+            return;
+        }
+
+        $database
+            ->setSharedTables($sharedTables)
+            ->setNamespace($namespace)
+            ->setDatabase($schema)
+            ->setTenant($originalTenant);
+    }
+
     public function testEvents(): void
     {
         $this->getDatabase()->getAuthorization()->skip(function () {