fix http2 feature is not enabled for native-tls ALPN (#2927)

Author: fox0

src/async_impl/client.rs

@@ -531,7 +531,11 @@ impl ClientBuilder {
                                 tls.request_alpns(&["h2"]);
                             }
                             HttpVersionPref::All => {
-                                tls.request_alpns(&["h2", "http/1.1"]);
+                                tls.request_alpns(&[
+                                    #[cfg(feature = "http2")]
+                                    "h2",
+                                    "http/1.1",
+                                ]);
                             }
                         }
                     }

tests/client.rs

@@ -371,6 +371,21 @@ fn use_preconfigured_rustls_default() {
         .expect("preconfigured rustls tls");
 }
 
+#[cfg(all(feature = "__tls", not(any(feature = "http2", feature = "http3")),))]
+#[tokio::test]
+async fn http1_only() {
+    let res = reqwest::Client::builder()
+        .build()
+        .expect("client builder")
+        .get("https://google.com")
+        .send()
+        .await
+        .expect("request");
+
+    assert_eq!(res.status(), reqwest::StatusCode::OK);
+    assert_eq!(res.version(), reqwest::Version::HTTP_11);
+}
+
 #[cfg(feature = "__rustls")]
 #[tokio::test]
 #[ignore = "Needs TLS support in the test server"]