Issue #560: Fixed bug when using a lamda as a Feign fallback (#576)

resilience4j-feign/src/main/java/io/github/resilience4j/feign/DefaultFallbackHandler.java

@@ -40,6 +40,7 @@ public CheckedFunction1<Object[], Object> decorate(CheckedFunction1<Object[], Ob
                                                        Predicate<Exception> filter) {
         validateFallback(fallback, method);
         Method fallbackMethod = getFallbackMethod(fallback, method);
+        fallbackMethod.setAccessible(true);
         return args -> {
             try {
                 return invocationCall.apply(args);

resilience4j-feign/src/test/java/io/github/resilience4j/feign/Resilience4jFeignFallbackLambdaTest.java

@@ -0,0 +1,75 @@
+/*
+ *
+ * Copyright 2019
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ *
+ *
+ */
+package io.github.resilience4j.feign;
+
+import io.github.resilience4j.feign.test.Issue560;
+import io.github.resilience4j.feign.test.TestService;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+import com.github.tomakehurst.wiremock.junit.WireMockRule;
+
+import static com.github.tomakehurst.wiremock.client.WireMock.aResponse;
+import static com.github.tomakehurst.wiremock.client.WireMock.get;
+import static com.github.tomakehurst.wiremock.client.WireMock.getRequestedFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.stubFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.urlPathEqualTo;
+import static com.github.tomakehurst.wiremock.client.WireMock.verify;
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests the integration of the {@link Resilience4jFeign} with the lambda as a fallback.
+ */
+public class Resilience4jFeignFallbackLambdaTest {
+
+    private static final String MOCK_URL = "http://localhost:8080/";
+
+    @Rule
+    public WireMockRule wireMockRule = new WireMockRule();
+
+    private TestService testService;
+
+    @Before
+    public void setUp() {
+        final FeignDecorators decorators = FeignDecorators.builder()
+                .withFallback(Issue560.createLambdaFallback())
+                .build();
+
+        this.testService = Resilience4jFeign.builder(decorators)
+                .target(TestService.class, MOCK_URL);
+    }
+
+    @Test
+    public void testFallback() {
+        setupStub();
+
+        final String result = testService.greeting();
+
+        assertThat(result).describedAs("Result").isEqualTo("fallback");
+        verify(1, getRequestedFor(urlPathEqualTo("/greeting")));
+    }
+
+    private void setupStub() {
+        stubFor(get(urlPathEqualTo("/greeting"))
+                .willReturn(aResponse()
+                        .withStatus(400)
+                        .withHeader("Content-Type", "text/plain")
+                        .withBody("Hello, world!")));
+    }
+}

resilience4j-feign/src/test/java/io/github/resilience4j/feign/test/Issue560.java

@@ -0,0 +1,17 @@
+package io.github.resilience4j.feign.test;
+
+/**
+ * <pre>
+ * Caused by: java.lang.IllegalAccessException:
+ * class io.github.resilience4j.feign.DefaultFallbackHandler
+ * cannot access a member of class
+ * io.github.resilience4j.feign.test.Issue560$$Lambda$93/0x0000000840169440 with modifiers "public"
+ * </pre>
+ * https://github.com/resilience4j/resilience4j/issues/560
+ */
+public class Issue560 {
+
+    public static TestService createLambdaFallback() {
+        return () -> "fallback";
+    }
+}