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// Copyright 2018 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.skylark;
import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
import com.google.devtools.build.lib.skylarkinterface.SkylarkInterfaceUtils;
import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
import com.google.devtools.build.lib.util.Classpath;
import java.lang.reflect.Method;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
/**
* Tests that bazel usages of {@link SkylarkCallable} and {@link SkylarkModule} abide by the
* contracts specified in their documentation.
*
* <p>Tests in this class use the java reflection API.</p>
*
* <p>This verification *would* be done via annotation processor, but annotation processors in
* java don't have access to the full set of information that the java reflection API has.</p>
*/
@RunWith(JUnit4.class)
public class SkylarkAnnotationContractTest {
// Common prefix of packages in bazel that may have classes that implement or extend a
// Skylark type.
private static final String MODULES_PACKAGE_PREFIX = "com/google/devtools/build";
/**
* Verifies that every class in bazel that implements or extends a Skylark type has a clearly
* resolvable type.
*
* <p>If this test fails, it indicates the following error scenario:
*
* <p>Suppose class A is a subclass of both B and C, where B and C are annotated with
* @SkylarkModule annotations (and are thus considered "skylark types"). If B is not a
* subclass of C (nor visa versa), then it's impossible to resolve whether A is of type
* B or if A is of type C. It's both! The way to resolve this is usually to have A be its own
* type (annotated with @SkylarkModule), and thus have the explicit type of A be semantically
* "B and C".
*/
@Test
public void testResolvableSkylarkModules() throws Exception {
for (Class<?> candidateClass : Classpath.findClasses(MODULES_PACKAGE_PREFIX)) {
SkylarkInterfaceUtils.getSkylarkModule(candidateClass);
}
}
/**
* Verifies that no class or interface has a method annotated with {@link SkylarkCallable} unless
* that class or interface is annotated with either {@link SkylarkGlobalLibrary} or with
* {@link SkylarkModule}.
*/
@Test
public void testSkylarkCallableScope() throws Exception {
for (Class<?> candidateClass : Classpath.findClasses(MODULES_PACKAGE_PREFIX)) {
if (SkylarkInterfaceUtils.getSkylarkModule(candidateClass) == null
&& !SkylarkInterfaceUtils.hasSkylarkGlobalLibrary(candidateClass)) {
for (Method method : candidateClass.getMethods()) {
SkylarkCallable callable = SkylarkInterfaceUtils.getSkylarkCallable(method);
if (callable != null && method.getDeclaringClass() == candidateClass) {
throw new AssertionError(String.format(
"Class %s has a SkylarkCallable method %s but is neither a @SkylarkModule nor a "
+ "@SkylarkGlobalLibrary",
candidateClass,
method.getName()));
}
}
}
}
}
}