Surface numeric :status pseudo-header from HTTP client codec (#213)

The codec was only publishing the reason phrase in headers["status"] on
the client path. That is good for logging but useless for callers that
need to branch on the actual HTTP status (e.g. to treat a 2xx as success
and a 4xx as a client error). Mirror the :method pseudo-header the
server path already writes and populate headers[":status"] with the
numeric response code before firing onHeaders.

Comes with two unit tests that feed a minimal HTTP/1.1 response through
the filter and assert both :status and the original status reason land
on the callbacks' header map — guarding against future regressions in
onHeadersComplete's client branch.

Author: gophergogo

src/filter/http_codec_filter.cc

@@ -621,6 +621,12 @@ HttpCodecFilter::ParserCallbacks::onHeadersComplete() {
     }
     parent_.current_stream_->headers[":method"] = method_str;
     parent_.current_stream_->method = method_str;
+  } else {
+    // Client mode: surface numeric response status as :status pseudo-header.
+    // Callers (HttpAsyncClient, etc.) need the numeric code, not just the
+    // reason phrase that onStatus already captures into headers["status"].
+    auto status_code = static_cast<uint16_t>(parent_.parser_->statusCode());
+    parent_.current_stream_->headers[":status"] = std::to_string(status_code);
   }
 
   // Check keep-alive

tests/filter/test_http_codec_filter.cc

@@ -589,6 +589,63 @@ TEST_F(HttpCodecFilterBodyTimeoutTest, ClientModeDisablesBodyTimeout) {
          "normal idle gaps, then crash the state machine on a live stream";
 }
 
+// ---------------------------------------------------------------------------
+// Client-mode response parsing surfaces numeric status as :status.
+//
+// The upstream onStatus callback only captures the reason phrase into
+// headers["status"] ("OK", "Not Found", ...). Callers that need to branch
+// on the actual HTTP status code (the HttpAsyncClient does) need the
+// numeric value. The codec populates headers[":status"] in onHeadersComplete
+// mirroring how server mode populates headers[":method"]; this test pins
+// that contract.
+// ---------------------------------------------------------------------------
+
+class HttpCodecFilterClientStatusTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    auto factory = event::createLibeventDispatcherFactory();
+    dispatcher_ = factory->createDispatcher("codec-status");
+    dispatcher_->run(event::RunType::NonBlock);
+    callbacks_ = std::make_unique<TestRequestCallbacks>();
+  }
+
+  void feedResponse(HttpCodecFilter& filter, const std::string& bytes) {
+    OwnedBuffer buf;
+    buf.add(bytes.c_str(), bytes.length());
+    filter.onNewConnection();
+    filter.onData(buf, false);
+  }
+
+  std::unique_ptr<event::Dispatcher> dispatcher_;
+  std::unique_ptr<TestRequestCallbacks> callbacks_;
+};
+
+TEST_F(HttpCodecFilterClientStatusTest, PopulatesNumericStatusPseudoHeader) {
+  HttpCodecFilter filter(*callbacks_, *dispatcher_, /*is_server=*/false);
+  feedResponse(filter,
+               "HTTP/1.1 404 Not Found\r\n"
+               "Content-Length: 0\r\n"
+               "Connection: close\r\n"
+               "\r\n");
+  ASSERT_TRUE(callbacks_->waitForHeaders());
+  auto headers = callbacks_->getHeaders();
+  EXPECT_EQ(headers[":status"], "404")
+      << "client mode must expose the numeric status as :status";
+  EXPECT_EQ(headers["status"], "Not Found")
+      << "reason phrase should still land in headers[\"status\"]";
+}
+
+TEST_F(HttpCodecFilterClientStatusTest, SurfacesSuccessStatus) {
+  HttpCodecFilter filter(*callbacks_, *dispatcher_, /*is_server=*/false);
+  feedResponse(filter,
+               "HTTP/1.1 202 Accepted\r\n"
+               "Content-Length: 0\r\n"
+               "Connection: close\r\n"
+               "\r\n");
+  ASSERT_TRUE(callbacks_->waitForHeaders());
+  EXPECT_EQ(callbacks_->getHeaders()[":status"], "202");
+}
+
 }  // namespace
 }  // namespace filter
 }  // namespace mcp