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Check deps only once in MicrometerObservationRegistryTestExecutionListener
Prior to this commit, the required runtime dependencies were checked via reflection each time an attempt was made to instantiate MicrometerObservationRegistryTestExecutionListener. Since it's sufficient to check for the presence of required runtime dependencies only once, this commit caches the results of the dependency checks in a static field. This commit also introduces automated tests for the runtime dependency checks in MicrometerObservationRegistryTestExecutionListener. See gh-30747
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-33
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2 files changed

+142
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‎spring-test/src/main/java/org/springframework/test/context/observation/MicrometerObservationRegistryTestExecutionListener.java

+30-33
Original file line numberDiff line numberDiff line change
@@ -16,8 +16,6 @@
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package org.springframework.test.context.observation;
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import java.lang.reflect.Method;
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import io.micrometer.observation.ObservationRegistry;
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import io.micrometer.observation.contextpropagation.ObservationThreadLocalAccessor;
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import org.apache.commons.logging.Log;
@@ -27,7 +25,6 @@
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import org.springframework.core.Conventions;
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import org.springframework.test.context.TestContext;
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import org.springframework.test.context.support.AbstractTestExecutionListener;
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import org.springframework.util.ReflectionUtils;
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/**
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* {@code TestExecutionListener} which provides support for Micrometer's
@@ -45,11 +42,6 @@ class MicrometerObservationRegistryTestExecutionListener extends AbstractTestExe
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private static final Log logger = LogFactory.getLog(MicrometerObservationRegistryTestExecutionListener.class);
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private static final String THREAD_LOCAL_ACCESSOR_CLASS_NAME = "io.micrometer.context.ThreadLocalAccessor";
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private static final String OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME =
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"io.micrometer.observation.contextpropagation.ObservationThreadLocalAccessor";
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/**
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* Attribute name for a {@link TestContext} attribute which contains the
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* {@link ObservationRegistry} that was previously stored in the
@@ -62,41 +54,46 @@ class MicrometerObservationRegistryTestExecutionListener extends AbstractTestExe
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private static final String PREVIOUS_OBSERVATION_REGISTRY = Conventions.getQualifiedAttributeName(
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MicrometerObservationRegistryTestExecutionListener.class, "previousObservationRegistry");
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static final String DEPENDENCIES_ERROR_MESSAGE = """
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MicrometerObservationRegistryTestExecutionListener requires \
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io.micrometer:micrometer-observation:1.10.8 or higher and \
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io.micrometer:context-propagation:1.0.3 or higher.""";
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public MicrometerObservationRegistryTestExecutionListener() {
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static final String THREAD_LOCAL_ACCESSOR_CLASS_NAME = "io.micrometer.context.ThreadLocalAccessor";
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static final String OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME =
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"io.micrometer.observation.contextpropagation.ObservationThreadLocalAccessor";
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private static final String ERROR_MESSAGE;
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static {
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// Trigger eager resolution of Micrometer Observation types to ensure that
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// this listener can be properly skipped when SpringFactoriesLoader attempts
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// to load it -- for example, if context-propagation and micrometer-observation
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// are not in the classpath or if the version of ObservationThreadLocalAccessor
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// present does not include the getObservationRegistry() method.
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ClassLoader classLoader = getClass().getClassLoader();
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String errorMessage = """
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MicrometerObservationRegistryTestExecutionListener requires \
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io.micrometer:micrometer-observation:1.10.8 or higher and \
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io.micrometer:context-propagation:1.0.3 or higher.""";
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String errorMessage = null;
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ClassLoader classLoader = MicrometerObservationRegistryTestExecutionListener.class.getClassLoader();
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String classToCheck = THREAD_LOCAL_ACCESSOR_CLASS_NAME;
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try {
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Class.forName(THREAD_LOCAL_ACCESSOR_CLASS_NAME, false, classLoader);
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Class<?> clazz = Class.forName(OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME, false, classLoader);
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Method method = ReflectionUtils.findMethod(clazz, "getObservationRegistry");
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if (method == null) {
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// We simulate "class not found" even though it's "method not found", since
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// the ClassNotFoundException will be processed in the subsequent catch-block.
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throw new ClassNotFoundException(OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME);
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}
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Class.forName(classToCheck, false, classLoader);
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classToCheck = OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME;
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Class<?> clazz = Class.forName(classToCheck, false, classLoader);
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clazz.getMethod("getObservationRegistry");
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}
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catch (Throwable ex) {
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// Ensure that we throw a NoClassDefFoundError so that the exception will be properly
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// handled in TestContextFailureHandler.
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// If the original exception was a ClassNotFoundException or NoClassDefFoundError,
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// we throw a NoClassDefFoundError with an augmented error message and omit the cause.
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if (ex instanceof ClassNotFoundException || ex instanceof NoClassDefFoundError) {
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throw new NoClassDefFoundError(ex.getMessage() + ". " + errorMessage);
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}
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// Otherwise, we throw a NoClassDefFoundError with the cause initialized.
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Error error = new NoClassDefFoundError(errorMessage);
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error.initCause(ex);
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throw error;
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errorMessage = classToCheck + ". " + DEPENDENCIES_ERROR_MESSAGE;
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}
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ERROR_MESSAGE = errorMessage;
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}
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public MicrometerObservationRegistryTestExecutionListener() {
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// If required dependencies are missing, throw a NoClassDefFoundError so
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// that this listener will be properly skipped in TestContextFailureHandler.
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if (ERROR_MESSAGE != null) {
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throw new NoClassDefFoundError(ERROR_MESSAGE);
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}
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}
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‎spring-test/src/test/java/org/springframework/test/context/observation/MicrometerObservationRegistryTestExecutionListenerDependencyTests.java

+112
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,112 @@
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/*
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* Copyright 2002-2023 the original author or authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* https://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.springframework.test.context.observation;
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import java.lang.reflect.Constructor;
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import java.lang.reflect.InvocationTargetException;
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import java.util.function.Predicate;
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import java.util.stream.IntStream;
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import org.junit.jupiter.api.Test;
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import org.springframework.core.OverridingClassLoader;
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import static org.assertj.core.api.Assertions.assertThat;
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import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
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import static org.assertj.core.api.Assertions.assertThatNoException;
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import static org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.DEPENDENCIES_ERROR_MESSAGE;
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import static org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME;
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import static org.springframework.test.context.observation.MicrometerObservationRegistryTestExecutionListener.THREAD_LOCAL_ACCESSOR_CLASS_NAME;
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/**
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* Unit tests for {@link MicrometerObservationRegistryTestExecutionListener}
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* behavior regarding required dependencies.
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*
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* @author Sam Brannen
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* @since 6.0.11
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*/
42+
class MicrometerObservationRegistryTestExecutionListenerDependencyTests {
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@Test
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void allDependenciesArePresent() throws Exception {
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FilteringClassLoader classLoader = new FilteringClassLoader(getClass().getClassLoader(), name -> false);
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Class<?> listenerClass = classLoader.loadClass(MicrometerObservationRegistryTestExecutionListener.class.getName());
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// Invoke multiple times to ensure consistency.
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IntStream.rangeClosed(1, 5).forEach(n -> assertThatNoException().isThrownBy(() -> instantiateListener(listenerClass)));
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}
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@Test
53+
void threadLocalAccessorIsNotPresent() throws Exception {
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assertNoClassDefFoundErrorIsThrown(THREAD_LOCAL_ACCESSOR_CLASS_NAME);
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}
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@Test
58+
void observationThreadLocalAccessorIsNotPresent() throws Exception {
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assertNoClassDefFoundErrorIsThrown(OBSERVATION_THREAD_LOCAL_ACCESSOR_CLASS_NAME);
60+
}
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62+
private void assertNoClassDefFoundErrorIsThrown(String missingClassName) throws Exception {
63+
FilteringClassLoader classLoader = new FilteringClassLoader(getClass().getClassLoader(), missingClassName::equals);
64+
Class<?> listenerClass = classLoader.loadClass(MicrometerObservationRegistryTestExecutionListener.class.getName());
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// Invoke multiple times to ensure the same error message is generated every time.
66+
IntStream.rangeClosed(1, 5).forEach(n -> assertExceptionThrown(missingClassName, listenerClass));
67+
}
68+
69+
private void assertExceptionThrown(String missingClassName, Class<?> listenerClass) {
70+
assertThatExceptionOfType(InvocationTargetException.class)
71+
.isThrownBy(() -> instantiateListener(listenerClass))
72+
.havingCause()
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.isInstanceOf(NoClassDefFoundError.class)
74+
.withMessage(missingClassName + ". " + DEPENDENCIES_ERROR_MESSAGE);
75+
}
76+
77+
private void instantiateListener(Class<?> listenerClass) throws Exception {
78+
assertThat(listenerClass).isNotNull();
79+
Constructor<?> constructor = listenerClass.getDeclaredConstructor();
80+
constructor.setAccessible(true);
81+
constructor.newInstance();
82+
}
83+
84+
85+
static class FilteringClassLoader extends OverridingClassLoader {
86+
87+
private static final Predicate<? super String> isListenerClass =
88+
MicrometerObservationRegistryTestExecutionListener.class.getName()::equals;
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90+
private final Predicate<String> classNameFilter;
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FilteringClassLoader(ClassLoader parent, Predicate<String> classNameFilter) {
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super(parent);
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this.classNameFilter = classNameFilter;
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}
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@Override
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protected boolean isEligibleForOverriding(String className) {
100+
return this.classNameFilter.or(isListenerClass).test(className);
101+
}
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@Override
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protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
105+
if (this.classNameFilter.test(name)) {
106+
throw new ClassNotFoundException(name);
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}
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return super.loadClass(name, resolve);
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}
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}
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}

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