Check name conflicts of functions in Funqy

Signed-off-by: Matej Vasek <[email protected]>

extensions/funqy/funqy-knative-events/deployment/src/test/java/io/quarkus/funqy/test/NameConflict.java

@@ -0,0 +1,17 @@
+package io.quarkus.funqy.test;
+
+import io.quarkus.funqy.Funq;
+
+public class NameConflict {
+
+    @Funq
+    public String function(String s) {
+        return s.toUpperCase();
+    }
+
+    @Funq
+    public int function(int i) {
+        return i * 2;
+    }
+
+}

extensions/funqy/funqy-knative-events/deployment/src/test/java/io/quarkus/funqy/test/NameConflictTest.java

@@ -0,0 +1,33 @@
+package io.quarkus.funqy.test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import java.io.*;
+import java.util.logging.Level;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import io.quarkus.test.QuarkusUnitTest;
+
+public class NameConflictTest {
+    @RegisterExtension
+    static QuarkusUnitTest test = new QuarkusUnitTest()
+            .withApplicationRoot(jar -> jar.addClass(NameConflict.class))
+            .setLogRecordPredicate(logRecord -> logRecord.getLevel().intValue() >= Level.WARNING.intValue() &&
+                    logRecord.getLoggerName().startsWith("io.quarkus.funqy"))
+            .assertLogRecords(logRecords -> {
+                boolean match = logRecords
+                        .stream()
+                        .anyMatch(logRecord -> logRecord.getMessage().contains("Name conflict"));
+                if (!match) {
+                    fail("Log does not contain message about name conflict.");
+                }
+            });
+
+    @Test
+    void test() {
+        assertTrue(true);
+    }
+}

extensions/funqy/funqy-server-common/runtime/src/main/java/io/quarkus/funqy/runtime/FunctionRegistry.java

@@ -5,15 +5,34 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import org.jboss.logging.Logger;
+
 public class FunctionRegistry {
     protected Map<String, FunctionInvoker> functions = new HashMap<>();
 
+    private static final Logger log = Logger.getLogger(FunctionRegistry.class);
+
     public void register(Class clz, String methodName, String descriptor, String functionName) {
+        String methodDescription = clz.getName() + "/" + methodName + descriptor;
+
+        FunctionInvoker fi = functions.get(functionName);
+        if (fi != null) {
+            String otherMethodDescription = fi.targetClass.getName() + "/" + fi.method.getName()
+                    + getMethodDescriptor(fi.method);
+            String msg = String.format("Name conflict: the name \"%s\" is shared by \"%s\" and \"%s\"." +
+                    " Consider using @Func(\"name-here\") annotation parameter to distinguish them.",
+                    functionName, methodDescription, otherMethodDescription);
+            log.warn(msg);
+        }
+
         for (Method m : clz.getMethods()) {
             if (m.getName().equals(methodName) && descriptor.equals(getMethodDescriptor(m))) {
                 functions.put(functionName, new FunctionInvoker(functionName, clz, m));
+                return;
             }
         }
+
+        throw new RuntimeException("Method \"" + methodDescription + "\" not found.");
     }
 
     public FunctionInvoker matchInvoker(String name) {