Throw InvalidArgumentException when an incorrect headers array is…

… provided (#2942)

* Throw `InvalidArgumentException` when an incorrect `headers` array is provided

As discussed in PR #2916 after it was merged an `InvalidArgumentException` is
more fitting, as passing an invalid `headers` array is a clear programming
error that needs to be fixed and not caught.

This is consistent with the validation of the other options, e.g. when using
`multipart` and `form_params` at the same time.

see #2916
see a2b8dd1

* Remove obsolete import in Client.php / ClientTest.php

src/Client.php

@@ -5,7 +5,6 @@
 use GuzzleHttp\Cookie\CookieJar;
 use GuzzleHttp\Exception\GuzzleException;
 use GuzzleHttp\Exception\InvalidArgumentException;
-use GuzzleHttp\Exception\RequestException;
 use GuzzleHttp\Promise as P;
 use GuzzleHttp\Promise\PromiseInterface;
 use Psr\Http\Message\RequestInterface;
@@ -346,7 +345,7 @@ private function applyOptions(RequestInterface $request, array &$options): Reque
 
         if (isset($options['headers'])) {
             if (array_keys($options['headers']) === range(0, count($options['headers']) - 1)) {
-                throw new RequestException('The headers array must have header name as keys.', $request);
+                throw new InvalidArgumentException('The headers array must have header name as keys.');
             }
             $modify['set_headers'] = $options['headers'];
             unset($options['headers']);

tests/ClientTest.php

@@ -4,7 +4,6 @@
 
 use GuzzleHttp\Client;
 use GuzzleHttp\Cookie\CookieJar;
-use GuzzleHttp\Exception\RequestException;
 use GuzzleHttp\Handler\MockHandler;
 use GuzzleHttp\HandlerStack;
 use GuzzleHttp\Middleware;
@@ -620,7 +619,7 @@ public function testSendWithInvalidHeader()
         $client = new Client(['handler' => $mock]);
         $request = new Request('GET', 'http://foo.com');
 
-        $this->expectException(RequestException::class);
+        $this->expectException(\GuzzleHttp\Exception\InvalidArgumentException::class);
         $client->send($request, ['headers'=>['X-Foo: Bar']]);
     }
 
@@ -630,7 +629,7 @@ public function testSendWithInvalidHeaders()
         $client = new Client(['handler' => $mock]);
         $request = new Request('GET', 'http://foo.com');
 
-        $this->expectException(RequestException::class);
+        $this->expectException(\GuzzleHttp\Exception\InvalidArgumentException::class);
         $client->send($request, ['headers'=>['X-Foo: Bar', 'X-Test: Fail']]);
     }