Throw error when json_encode fails

src/Curl/Curl.php

@@ -134,6 +134,7 @@ class Curl
      * @param  $data
      *
      * @return array|string
+     * @throws \ErrorException
      */
     public function buildPostData($data)
     {
@@ -142,9 +143,9 @@ class Curl
             // Return JSON-encoded string when the request's content-type is JSON.
             if (isset($this->headers['Content-Type']) &&
                 preg_match($this->jsonPattern, $this->headers['Content-Type'])) {
-                $json_str = json_encode($data);
-                if (!($json_str === false)) {
-                    $data = $json_str;
+                $data = json_encode($data);
+                if (!(json_last_error() === JSON_ERROR_NONE)) {
+                    throw new \ErrorException('json_encode error: ' . json_last_error_msg());
                 }
             } else {
                 // Manually build a single-dimensional array from a multi-dimensional array as using curl_setopt($ch,

tests/PHPCurlClass/PHPCurlClassTest.php

@@ -1381,6 +1381,20 @@ class CurlTest extends \PHPUnit\Framework\TestCase
         }
     }
 
+    /**
+     * @expectedException \ErrorException
+     */
+    public function testJsonEncode()
+    {
+        $data = array(
+            'malformed' => pack('H*', 'c32e'),
+        );
+
+        $test = new Test();
+        $test->curl->setHeader('Content-Type', 'application/json');
+        $test->server('post_json', 'POST', $data);
+    }
+
     public function testJsonDecoderOptions()
     {
         // Implicit default json decoder should return object.