Test that crashes Guice inside Guava

This test causes Guice to violate the requirements of Guava's
LoadingCache by triggering a recursive load.

The recursive load crashes either with an UncheckedExecutionException
(bad) or causes a deadlock (terrible).

#785

Author: squarejesse

core/test/com/google/inject/RecursiveLoadTest.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2020 Google Inc.
+ *
+ * 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 com.google.inject;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+@RunWith(JUnit4.class)
+public final class RecursiveLoadTest {
+  /**
+   * This test uses failed optional bindings to trigger a recursive load crash.
+   * https://github.com/google/guice/issues/785
+   */
+  @Test public void recursiveLoad() {
+    Guice.createInjector(new AbstractModule() {
+      @Override protected void configure() {
+        bind(A.class);
+      }
+    });
+  }
+
+  static class A {
+    @Inject B b;
+  }
+
+  static class B {
+    @Inject C c;
+  }
+
+  static class C {
+    @Inject(optional = true) D d;
+    @Inject E e;
+  }
+
+  static class D {
+    @Inject B b;
+    @Inject Unresolved unresolved;
+  }
+
+  static class E {
+    @Inject B b;
+  }
+
+  interface Unresolved {
+  }
+}