Improve error handling when sending data to DNS server fails (macOS)

Author: clue

.github/workflows/ci.yml

@@ -33,6 +33,19 @@ jobs:
       - run: vendor/bin/phpunit --coverage-text -c phpunit.xml.legacy
         if: ${{ matrix.php < 7.3 }}
 
+  PHPUnit-macOS:
+    name: PHPUnit (macOS)
+    runs-on: macos-10.15
+    continue-on-error: true
+    steps:
+      - uses: actions/checkout@v2
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.0
+          coverage: xdebug
+      - run: composer install
+      - run: vendor/bin/phpunit --coverage-text
+
   PHPUnit-hhvm:
     name: PHPUnit (HHVM)
     runs-on: ubuntu-18.04

src/Query/UdpTransportExecutor.php

@@ -137,7 +137,20 @@ public function query(Query $query)
 
         // set socket to non-blocking and immediately try to send (fill write buffer)
         \stream_set_blocking($socket, false);
-        \fwrite($socket, $queryData);
+        $written = @\fwrite($socket, $queryData);
+
+        if ($written !== \strlen($queryData)) {
+            // Write may potentially fail, but most common errors are already caught by connection check above.
+            // Among others, macOS is known to report here when trying to send to broadcast address.
+            // @codeCoverageIgnoreStart
+            $error = \error_get_last();
+            \preg_match('/errno=(\d+) (.+)/', $error['message'], $m);
+            return \React\Promise\reject(new \RuntimeException(
+                'DNS query for ' . $query->name . ' failed: Unable to send query to DNS server ('  . (isset($m[2]) ? $m[2] : $error['message']) . ')',
+                isset($m[1]) ? (int) $m[1] : 0
+            ));
+            // @codeCoverageIgnoreEnd
+        }
 
         $loop = $this->loop;
         $deferred = new Deferred(function () use ($loop, $socket, $query) {

tests/Query/UdpTransportExecutorTest.php

@@ -120,7 +120,35 @@ public function testQueryRejectsIfServerConnectionFails()
         $promise = $executor->query($query);
 
         $this->assertInstanceOf('React\Promise\PromiseInterface', $promise);
-        $promise->then(null, $this->expectCallableOnce());
+
+        $exception = null;
+        $promise->then(null, function ($reason) use (&$exception) {
+            $exception = $reason;
+        });
+
+        $this->setExpectedException('RuntimeException', 'Unable to connect to DNS server (Failed to parse address "///")');
+        throw $exception;
+    }
+
+    public function testQueryRejectsIfSendToServerFailsAfterConnection()
+    {
+        $loop = $this->getMockBuilder('React\EventLoop\LoopInterface')->getMock();
+        $loop->expects($this->never())->method('addReadStream');
+
+        $executor = new UdpTransportExecutor('255.255.255.255', $loop);
+
+        $query = new Query('google.com', Message::TYPE_A, Message::CLASS_IN);
+        $promise = $executor->query($query);
+
+        $this->assertInstanceOf('React\Promise\PromiseInterface', $promise);
+
+        $exception = null;
+        $promise->then(null, function ($reason) use (&$exception) {
+            $exception = $reason;
+        });
+
+        $this->setExpectedException('RuntimeException', 'to DNS server (Permission denied)', SOCKET_EACCES);
+        throw $exception;
     }
 
     /**