errors: more verbose error reporting in StreamConnection

This patch makes error reporting in `read` and `send` methods of
`StreamConnection` more verbose to provide aid in debugging network
errors.

src/Connection/StreamConnection.php

@@ -123,7 +123,7 @@ public function open() : Greeting
             return $this->greeting = Greeting::unknown();
         }
 
-        $greeting = $this->read(Greeting::SIZE_BYTES, 'Unable to read greeting');
+        $greeting = $this->read(Greeting::SIZE_BYTES, 'Error reading greeting');
 
         return $this->greeting = Greeting::parse($greeting);
     }
@@ -146,14 +146,18 @@ public function isClosed() : bool
 
     public function send(string $data) : string
     {
-        if (!$this->stream || !\fwrite($this->stream, $data)) {
-            throw new CommunicationFailed('Unable to write request');
+        if (!$this->stream) {
+            throw new CommunicationFailed('Error writing request: connection closed');
         }
 
-        $length = $this->read(PacketLength::SIZE_BYTES, 'Unable to read response length');
+        if (!\fwrite($this->stream, $data)) {
+            throw CommunicationFailed::withLastPhpError("Error writing request");
+        }
+
+        $length = $this->read(PacketLength::SIZE_BYTES, 'Error reading response length');
         $length = PacketLength::unpack($length);
 
-        return $this->read($length, 'Unable to read response');
+        return $this->read($length, 'Error reading response');
     }
 
     private function read(int $length, string $errorMessage) : string
@@ -165,6 +169,11 @@ private function read(int $length, string $errorMessage) : string
 
         /** @psalm-suppress PossiblyNullArgument */
         $meta = \stream_get_meta_data($this->stream);
-        throw new CommunicationFailed($meta['timed_out'] ? 'Read timed out' : $errorMessage);
+        if ($meta['timed_out']) {
+            throw new CommunicationFailed('Read timed out');
+        }
+
+
+        throw CommunicationFailed::withLastPhpError($errorMessage);
     }
 }

src/Exception/CommunicationFailed.php

@@ -15,4 +15,10 @@
 
 final class CommunicationFailed extends \RuntimeException implements ClientException
 {
+    public static function withLastPhpError(string $errorMessage): self
+    {
+        $error = error_get_last();
+
+        return new self($error ? \sprintf("%s: %s", $errorMessage, $error['message']) : $errorMessage);
+    }
 }

tests/Integration/ClientMiddlewareTest.php

@@ -140,7 +140,7 @@ public function testThrowOnBrokenConnection() : void
         $client->ping();
 
         $this->expectException(CommunicationFailed::class);
-        $this->expectExceptionMessage('Unable to write request');
+        $this->expectExceptionMessage('Error writing request: fwrite(): Send of 15 bytes failed with errno=32 Broken pipe');
         $client->ping();
     }
 

tests/Integration/Connection/ConnectionTest.php

@@ -190,12 +190,13 @@ public function testUnexpectedResponse() : void
     public function testOpenConnectionHandlesTheMissingGreetingCorrectly() : void
     {
         $clientBuilder = ClientBuilder::createForFakeServer();
+        $uri = $clientBuilder->getUri();
 
         FakeServerBuilder::create(
             new AtConnectionHandler(1, new WriteHandler('')),
             new AtConnectionHandler(2, new WriteHandler(GreetingDataProvider::generateGreeting()))
         )
-            ->setUri($clientBuilder->getUri())
+            ->setUri($uri)
             ->start();
 
         $client = $clientBuilder->build();
@@ -205,7 +206,11 @@ public function testOpenConnectionHandlesTheMissingGreetingCorrectly() : void
             $connection->open();
             self::fail('Connection not established');
         } catch (CommunicationFailed $e) {
-            self::assertSame('Unable to read greeting', $e->getMessage());
+            self::assertSame(
+                sprintf('Error reading greeting: ' .
+                    'stream_socket_client(): Unable to connect to %s ' .
+                    '(Connection refused)', $uri)
+                , $e->getMessage());
             // At that point the connection was successfully established,
             // but the greeting message was not read
         }

tests/Integration/Connection/ParseGreetingTest.php

@@ -27,17 +27,22 @@ final class ParseGreetingTest extends TestCase
     public function testParseGreetingWithInvalidServerName(string $greeting) : void
     {
         $clientBuilder = ClientBuilder::createForFakeServer();
+        $uri = $clientBuilder->getUri();
 
         FakeServerBuilder::create(new WriteHandler($greeting))
-            ->setUri($clientBuilder->getUri())
+            ->setUri($uri)
             ->start();
 
         $client = $clientBuilder->build();
 
         try {
             $client->ping();
         } catch (CommunicationFailed $e) {
-            self::assertSame('Unable to read greeting', $e->getMessage());
+            self::assertSame(
+                sprintf("Error reading greeting: " .
+                    "stream_socket_client(): Unable to connect to %s " .
+                    "(Connection refused)", $uri),
+                $e->getMessage());
 
             return;
         } catch (\RuntimeException $e) {

tests/Integration/Connection/ReadTest.php

@@ -35,34 +35,44 @@ public function testReadLargeResponse() : void
     public function testReadEmptyGreeting() : void
     {
         $clientBuilder = ClientBuilder::createForFakeServer();
+        $uri = $clientBuilder->getUri();
 
         FakeServerBuilder::create()
-            ->setUri($clientBuilder->getUri())
+            ->setUri($uri)
             ->start();
 
         $client = $clientBuilder->build();
 
         $this->expectException(CommunicationFailed::class);
-        $this->expectExceptionMessage('Unable to read greeting');
+        $this->expectExceptionMessage(
+            \sprintf('Error reading greeting: ' .
+                     'stream_socket_client(): Unable to connect to %s ' .
+                     '(Connection refused)', $uri)
+        );
 
         $client->ping();
     }
 
     public function testUnableToReadResponseLength() : void
     {
         $clientBuilder = ClientBuilder::createForFakeServer();
+        $uri = $clientBuilder->getUri();
 
         FakeServerBuilder::create(
             new WriteHandler(GreetingDataProvider::generateGreeting()),
             new SleepHandler(1)
         )
-            ->setUri($clientBuilder->getUri())
+            ->setUri($uri)
             ->start();
 
         $client = $clientBuilder->build();
 
         $this->expectException(CommunicationFailed::class);
-        $this->expectExceptionMessage('Unable to read response length');
+        $this->expectExceptionMessage(
+            \sprintf('Error reading response length: ' .
+                'stream_socket_client(): Unable to connect to %s ' .
+                '(Connection refused)', $uri)
+        );
 
         $client->ping();
     }
@@ -90,19 +100,24 @@ public function testReadResponseLengthTimedOut() : void
     public function testUnableToReadResponse() : void
     {
         $clientBuilder = ClientBuilder::createForFakeServer();
+        $uri = $clientBuilder->getUri();
 
         FakeServerBuilder::create(
             new WriteHandler(GreetingDataProvider::generateGreeting()),
             new WriteHandler(PacketLength::pack(42)),
             new SleepHandler(1)
         )
-            ->setUri($clientBuilder->getUri())
+            ->setUri($uri)
             ->start();
 
         $client = $clientBuilder->build();
 
         $this->expectException(CommunicationFailed::class);
-        $this->expectExceptionMessage('Unable to read response');
+        $this->expectExceptionMessage(
+            \sprintf('Error reading response: ' .
+                'stream_socket_client(): Unable to connect to %s ' .
+                '(Connection refused)', $uri)
+        );
 
         $client->ping();
     }