fix(server): Respect Expect header only when http proto > 1.0 (#3294)

src/proto/h1/conn.rs

@@ -257,7 +257,7 @@ where
             if !T::should_read_first() {
                 self.try_keep_alive(cx);
             }
-        } else if msg.expect_continue {
+        } else if msg.expect_continue && msg.head.version.gt(&Version::HTTP_10) {
             self.state.reading = Reading::Continue(Decoder::new(msg.decode));
             wants = wants.add(Wants::EXPECT);
         } else {

tests/server.rs

@@ -916,6 +916,39 @@ fn expect_continue_accepts_upper_cased_expectation() {
     assert_eq!(body, msg);
 }
 
+#[test]
+fn expect_continue_but_http_10_is_ignored() {
+    let server = serve();
+    let mut req = connect(server.addr());
+    server.reply();
+
+    req.write_all(
+        b"\
+        POST /foo HTTP/1.0\r\n\
+        Host: example.domain\r\n\
+        Expect: 100-Continue\r\n\
+        Content-Length: 5\r\n\
+        Connection: Close\r\n\
+        \r\n\
+    ",
+    )
+    .expect("write 1");
+
+    let msg = b"hello";
+    req.write_all(msg).expect("write 2");
+
+    let s_line = b"HTTP/1.0 200 OK\r\n";
+    let mut buf = vec![0; s_line.len()];
+    req.read_exact(&mut buf).expect("read 1");
+    assert_eq!(buf, s_line);
+
+    let mut body = String::new();
+    req.read_to_string(&mut body).expect("read 2");
+
+    let body = server.body();
+    assert_eq!(body, msg);
+}
+
 #[test]
 fn expect_continue_but_no_body_is_ignored() {
     let server = serve();