Add check and test for non-scalar values in primary key

src/Keboola/CsvMap/Mapper.php

@@ -119,6 +119,7 @@ protected function parseRow($row, array $userData)
                     }
 
                     $primaryKeyValue = $this->getPrimaryKeyValues($row, $userData);
+                    $this->checkPrimaryKeyValues($primaryKeyValue);
 
                     if (empty($settings['parentKey']['disable'])) {
                         if (empty($this->getPrimaryKey())) {
@@ -161,6 +162,17 @@ protected function parseRow($row, array $userData)
         return $result;
     }
 
+    private function checkPrimaryKeyValues(array $values)
+    {
+        foreach ($values as $value) {
+            if (!is_scalar($value) && !is_null($value)) {
+                throw new BadConfigException(
+                    'Only scalar values are allowed in primary key. Primary key: ' . json_encode($values)
+                );
+            }
+        }
+    }
+
     public function getPrimaryKey()
     {
         $primaryKey = [];

tests/Keboola/CsvMap/MapperNotAllowedPrimaryKeyValueTest.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace Keboola\CsvMap;
+
+class MapperNotAllowedPrimaryKeyValueTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @expectedException \Keboola\CsvMap\Exception\BadConfigException
+     * @expectedExceptionMessage Only scalar values are allowed in primary key.
+     * Primary key: [{"$oid":"5716054bee6e764c94fa85a6"}]
+     */
+    public function testNotAllowedPrimaryKeyValue()
+    {
+        $config = [
+            '_id' => [
+                'type' => 'column',
+                'mapping' => [
+                    'destination' => 'id',
+                    'primaryKey' => true,
+                ]
+            ],
+            'coord' => [
+                'type' => 'table',
+                'destination' => 'coord',
+                'tableMapping' => [
+                    'a' => 'a',
+                ]
+            ]
+        ];
+
+        $data = $this->getSampleData();
+
+        $parser = new Mapper($config);
+        $parser->parse($data);
+    }
+
+    protected function getSampleData()
+    {
+        $json = <<<JSON
+[
+  {
+    "_id": {
+      "\$oid": "5716054bee6e764c94fa85a6"
+    },
+    "coord": [
+      {
+        "a": 1
+      },
+      {
+        "a": 2
+      }
+    ]
+  }
+]
+JSON;
+        return json_decode($json);
+    }
+}