Restore exceptions for BC

Closes #249.

src/Connection/Http2ConnectionException.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Amp\Http\Client\Connection;
+
+use Amp\Http\Client\HttpException;
+
+/**
+ * @deprecated Exception moved to amphp/http. Catch the base exception class (HttpException) instead.
+ */
+final class Http2ConnectionException extends HttpException
+{
+    public function __construct(string $message, int $code, ?\Throwable $previous = null)
+    {
+        parent::__construct($message, $code, $previous);
+    }
+}

src/Connection/Http2StreamException.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Amp\Http\Client\Connection;
+
+use Amp\Http\Client\HttpException;
+
+/**
+ * @deprecated Exception moved to amphp/http. Catch the base exception class (HttpException) instead.
+ */
+final class Http2StreamException extends HttpException
+{
+    /** @var int */
+    private $streamId;
+
+    public function __construct(string $message, int $streamId, int $code, ?\Throwable $previous = null)
+    {
+        parent::__construct($message, $code, $previous);
+        $this->streamId = $streamId;
+    }
+
+    public function getStreamId(): int
+    {
+        return $this->streamId;
+    }
+}

src/Connection/Internal/Http2ConnectionProcessor.php

@@ -199,7 +199,7 @@ public function handleShutdown(int $lastId, int $error): void
             $error
         );
 
-        $this->shutdown($lastId, new Http2ConnectionException($message, $error));
+        $this->shutdown($lastId, new HttpException($message, $error));
     }
 
     public function handleStreamWindowIncrement(int $streamId, int $windowSize): void
@@ -632,12 +632,10 @@ public function handleStreamException(Http2StreamException $exception): void
         $id = $exception->getStreamId();
         $code = $exception->getCode();
 
+        $exception = new HttpException($exception->getMessage(), 0, $exception);
+
         if ($code === Http2Parser::REFUSED_STREAM) {
-            $exception = new UnprocessedRequestException(new HttpException(
-                $exception->getMessage(),
-                0,
-                $exception
-            ));
+            $exception = new UnprocessedRequestException($exception);
         }
 
         $this->writeFrame(Http2Parser::RST_STREAM, Http2Parser::NO_FLAG, $id, \pack("N", $code));
@@ -649,7 +647,7 @@ public function handleStreamException(Http2StreamException $exception): void
 
     public function handleConnectionException(Http2ConnectionException $exception): void
     {
-        $this->shutdown(null, $exception);
+        $this->shutdown(null, new HttpException($exception->getMessage(), 0, $exception));
     }
 
     public function handleData(int $streamId, string $data): void
@@ -994,9 +992,9 @@ private function run(): \Generator
                 \assert($return === null);
             }
 
-            $this->shutdown(null);
+            $this->shutdown();
         } catch (\Throwable $exception) {
-            $this->shutdown(null, $exception);
+            $this->shutdown(null, new HttpException("The HTTP/2 connection closed unexpectedly", 0, $exception));
         }
     }
 
@@ -1167,13 +1165,13 @@ private function releaseStream(int $streamId, ?\Throwable $exception = null): vo
 
         $stream = $this->streams[$streamId];
 
-        $exception = $exception ?? new Http2StreamException(
-            "Stream closed unexpectedly",
-            $streamId,
-            Http2Parser::INTERNAL_ERROR
-        );
-
         if ($stream->responsePending || $stream->body || $stream->trailers) {
+            $exception = $exception ?? new HttpException(\sprintf("Stream %d closed unexpectedly", $streamId));
+
+            if (!$exception instanceof HttpException && !$exception instanceof CancelledException) {
+                $exception = new HttpException($exception->getMessage(), 0, $exception);
+            }
+
             /** @var Deferred[]|Emitter[] $deferredAndEmitter */
             $deferredAndEmitter = [];
 
@@ -1287,13 +1285,13 @@ private function ping(): Promise
     }
 
     /**
-     * @param int|null        $lastId ID of last processed frame. Null to use the last opened frame ID or 0 if no
-     *                        streams have been opened.
-     * @param \Throwable|null $reason
+     * @param int|null           $lastId ID of last processed frame. Null to use the last opened frame ID or 0 if no
+     *                                   streams have been opened.
+     * @param HttpException|null $reason
      *
      * @return Promise
      */
-    private function shutdown(?int $lastId = null, ?\Throwable $reason = null): Promise
+    private function shutdown(?int $lastId = null, ?HttpException $reason = null): Promise
     {
         if ($this->onClose === null) {
             return new Success;

test/Connection/Http2ConnectionTest.php

@@ -2,11 +2,11 @@
 
 namespace Amp\Http\Client\Connection;
 
+use Amp\Http\Client\HttpException;
 use Amp\Http\Client\Request;
 use Amp\Http\Client\Response;
 use Amp\Http\Client\Trailers;
 use Amp\Http\HPack;
-use Amp\Http\Http2\Http2ConnectionException;
 use Amp\Http\Http2\Http2Parser;
 use Amp\Http\Status;
 use Amp\NullCancellationToken;
@@ -78,7 +78,7 @@ public function testSwitchingProtocols(): \Generator
             ["date", formatDateHeader()],
         ]), Http2Parser::HEADERS, Http2Parser::END_HEADERS, 1));
 
-        $this->expectException(Http2ConnectionException::class);
+        $this->expectException(HttpException::class);
         $this->expectExceptionMessage('Switching Protocols (101) is not part of HTTP/2');
 
         yield $stream->request($request, new NullCancellationToken);