Fail when attempting to enable h2c without enabling HTTP/2

Author: DerGuteMoritz

src/aleph/http/server.clj

@@ -759,10 +759,12 @@
                                   :http1-pipeline-transform http1-pipeline-transform
                                   :continue-executor continue-executor))]
 
-    (when (and (not ssl-context)
-               (not use-h2c?)
-               (some #{:http2} http-versions))
-      (throw (IllegalArgumentException. "HTTP/2 requires ssl-context to be given or use-h2c? to be true.")))
+    (if (some #{:http2} http-versions)
+      (when (and (not ssl-context)
+                 (not use-h2c?))
+        (throw (IllegalArgumentException. "HTTP/2 requires ssl-context to be given or use-h2c? to be true.")))
+      (when use-h2c?
+        (throw (IllegalArgumentException. "use-h2c? may only be true when HTTP/2 is enabled."))))
 
     (when (and ssl-context
                use-h2c?)

test/aleph/http_test.clj

@@ -1416,4 +1416,10 @@
                    :http-versions [:http2]
                    :ssl-context test-ssl/server-ssl-context-opts})]
       (is (instance? IllegalArgumentException result))
-      (is (= "use-h2c? must not be true when ssl-context is given." (ex-message result))))))
+      (is (= "use-h2c? must not be true when ssl-context is given." (ex-message result)))))
+  (testing "h2c without HTTP/2"
+    (let [result (try-start-server
+                  {:use-h2c? true
+                   :http-versions [:http1]})]
+      (is (instance? IllegalArgumentException result))
+      (is (= "use-h2c? may only be true when HTTP/2 is enabled." (ex-message result))))))