Add Android API-friendliness checks

instrumentation-api/build.gradle.kts

@@ -1,5 +1,3 @@
-import ru.vyarus.gradle.plugin.animalsniffer.AnimalSniffer
-
 plugins {
   id("org.xbib.gradle.plugin.jflex")
 
@@ -67,28 +65,4 @@ tasks {
       isFailOnNoMatchingTests = false
     }
   }
-
-  withType<AnimalSniffer>().configureEach {
-    // we catch NoClassDefFoundError when use caffeine3 is not available on classpath and fall back to caffeine2
-    exclude("**/internal/shaded/caffeine3/**")
-
-    ignoreClasses = listOf(
-      // ignore shaded caffeine3 references
-      "io.opentelemetry.instrumentation.api.internal.shaded.caffeine3.cache.Caffeine",
-      "io.opentelemetry.instrumentation.api.internal.shaded.caffeine3.cache.Cache",
-
-      // these are being referenced by some caffeine2 classes, but we don't use them
-      "java.util.concurrent.CompletableFuture",
-      "java.util.concurrent.CompletionException",
-      "java.util.concurrent.CompletionStage",
-      "java.util.concurrent.ForkJoinPool",
-      "java.util.concurrent.ConcurrentHashMap",
-      // LongAdder is also referenced by our own SupportabilityMetrics; only if agent debug is enabled though
-      "java.util.concurrent.atomic.LongAdder",
-
-      // these standard Java classes seem to be desugared properly
-      "java.lang.ClassValue",
-      "sun.misc.Unsafe",
-    )
-  }
 }

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/JdkErrorCauseExtractor.java

@@ -7,23 +7,40 @@
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.UndeclaredThrowableException;
-import java.util.concurrent.CompletionException;
 import java.util.concurrent.ExecutionException;
+import javax.annotation.Nullable;
 
 final class JdkErrorCauseExtractor implements ErrorCauseExtractor {
   static final ErrorCauseExtractor INSTANCE = new JdkErrorCauseExtractor();
 
+  @Nullable
+  private static final Class<?> COMPLETION_EXCEPTION_CLASS = getCompletionExceptionClass();
+
   @Override
   public Throwable extractCause(Throwable error) {
     if (error.getCause() != null
         && (error instanceof ExecutionException
-            || error instanceof CompletionException
+            || isInstanceOfCompletionException(error)
             || error instanceof InvocationTargetException
             || error instanceof UndeclaredThrowableException)) {
       return extractCause(error.getCause());
     }
     return error;
   }
 
+  private static boolean isInstanceOfCompletionException(Throwable error) {
+    return COMPLETION_EXCEPTION_CLASS != null && COMPLETION_EXCEPTION_CLASS.isInstance(error);
+  }
+
+  @Nullable
+  private static Class<?> getCompletionExceptionClass() {
+    try {
+      return Class.forName("java.util.concurrent.CompletionException");
+    } catch (ClassNotFoundException e) {
+      // Android level 21 does not support java.util.concurrent.CompletionException
+      return null;
+    }
+  }
+
   private JdkErrorCauseExtractor() {}
 }

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/tracer/BaseTracer.java

@@ -22,9 +22,9 @@
 import io.opentelemetry.instrumentation.api.internal.SupportabilityMetrics;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.UndeclaredThrowableException;
-import java.util.concurrent.CompletionException;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
+import javax.annotation.Nullable;
 
 /**
  * Base class for all instrumentation specific tracer implementations.
@@ -48,6 +48,9 @@
 public abstract class BaseTracer {
   private static final SupportabilityMetrics supportability = SupportabilityMetrics.instance();
 
+  @Nullable
+  private static final Class<?> COMPLETION_EXCEPTION_CLASS = getCompletionExceptionClass();
+
   private final Tracer tracer;
   private final ContextPropagators propagators;
 
@@ -242,7 +245,7 @@ public void onException(Context context, Throwable throwable) {
   protected Throwable unwrapThrowable(Throwable throwable) {
     if (throwable.getCause() != null
         && (throwable instanceof ExecutionException
-            || throwable instanceof CompletionException
+            || isInstanceOfCompletionException(throwable)
             || throwable instanceof InvocationTargetException
             || throwable instanceof UndeclaredThrowableException)) {
       return unwrapThrowable(throwable.getCause());
@@ -283,4 +286,18 @@ public <C> Context extract(C carrier, TextMapGetter<C> getter) {
   public <C> void inject(Context context, C carrier, TextMapSetter<C> setter) {
     propagators.getTextMapPropagator().inject(context, carrier, setter);
   }
+
+  private static boolean isInstanceOfCompletionException(Throwable error) {
+    return COMPLETION_EXCEPTION_CLASS != null && COMPLETION_EXCEPTION_CLASS.isInstance(error);
+  }
+
+  @Nullable
+  private static Class<?> getCompletionExceptionClass() {
+    try {
+      return Class.forName("java.util.concurrent.CompletionException");
+    } catch (ClassNotFoundException e) {
+      // Android level 21 does not support java.util.concurrent.CompletionException
+      return null;
+    }
+  }
 }