Implement ErrorReceivers support (#45)

* Implement TryOnError support This implements support for trying delegate onError calls if they opt in by implementing a new `TryOnError` interface. This will likely need to rely on guarded delegate call machinery, and need to figure out whether that should be another config or just supersede/defer to the existing config. Resolves #24 * Split reportError and createError * Add DeliverModifiedException marker type * Update observers for new DeliverModifiedException API * Rename new marker interfaces TryOnError -> RxDogTagErrorReceiver DeliverModifiedException -> RxDogTagModifiedExceptionReceiver * Rename new marker interfaces TryOnError -> RxDogTagErrorReceiver DeliverModifiedException -> RxDogTagModifiedExceptionReceiver * Spotless * Spotless
uber · Sep 15, 2019 · 864fba8 · 864fba8
1 parent 0453cd3
commit 864fba8
Show file tree

Hide file tree

Showing 10 changed files with 333 additions and 41 deletions.
diff --git a/gradle/dependencies.gradle b/gradle/dependencies.gradle
@@ -23,7 +23,7 @@ def versions = [
     jmhPlugin: '0.4.8',
     nullawayPlugin: '0.1',
     dokka: '0.9.18',
-    spotless: '3.21.1'
+    spotless: '3.24.2'
 ]
 
 def build = [

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagCompletableObserver.java b/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagCompletableObserver.java
@@ -15,6 +15,7 @@
  */
 package com.uber.rxdogtag;
 
+import static com.uber.rxdogtag.RxDogTag.createException;
 import static com.uber.rxdogtag.RxDogTag.guardedDelegateCall;
 import static com.uber.rxdogtag.RxDogTag.reportError;
 
@@ -55,7 +56,17 @@ public void onSubscribe(Disposable d) {
 
   @Override
   public void onError(Throwable e) {
-    reportError(config, t, e, null);
+    if (delegate instanceof RxDogTagErrorReceiver) {
+      if (delegate instanceof RxDogTagTaggedExceptionReceiver) {
+        delegate.onError(createException(config, t, e, null));
+      } else if (config.guardObserverCallbacks) {
+        guardedDelegateCall(e2 -> reportError(config, t, e2, "onError"), () -> delegate.onError(e));
+      } else {
+        delegate.onError(e);
+      }
+    } else {
+      reportError(config, t, e, null);
+    }
   }
 
   @Override

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagMaybeObserver.java b/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagMaybeObserver.java
@@ -15,6 +15,7 @@
  */
 package com.uber.rxdogtag;
 
+import static com.uber.rxdogtag.RxDogTag.createException;
 import static com.uber.rxdogtag.RxDogTag.guardedDelegateCall;
 import static com.uber.rxdogtag.RxDogTag.reportError;
 
@@ -68,7 +69,17 @@ public void onSuccess(T t) {
 
   @Override
   public void onError(Throwable e) {
-    reportError(config, t, e, null);
+    if (delegate instanceof RxDogTagErrorReceiver) {
+      if (delegate instanceof RxDogTagTaggedExceptionReceiver) {
+        delegate.onError(createException(config, t, e, null));
+      } else if (config.guardObserverCallbacks) {
+        guardedDelegateCall(e2 -> reportError(config, t, e2, "onError"), () -> delegate.onError(e));
+      } else {
+        delegate.onError(e);
+      }
+    } else {
+      reportError(config, t, e, null);
+    }
   }
 
   @Override

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagObserver.java b/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagObserver.java
@@ -15,6 +15,7 @@
  */
 package com.uber.rxdogtag;
 
+import static com.uber.rxdogtag.RxDogTag.createException;
 import static com.uber.rxdogtag.RxDogTag.guardedDelegateCall;
 import static com.uber.rxdogtag.RxDogTag.reportError;
 
@@ -66,7 +67,17 @@ public void onNext(T t) {
 
   @Override
   public void onError(Throwable e) {
-    reportError(config, t, e, null);
+    if (delegate instanceof RxDogTagErrorReceiver) {
+      if (delegate instanceof RxDogTagTaggedExceptionReceiver) {
+        delegate.onError(createException(config, t, e, null));
+      } else if (config.guardObserverCallbacks) {
+        guardedDelegateCall(e2 -> reportError(config, t, e2, "onError"), () -> delegate.onError(e));
+      } else {
+        delegate.onError(e);
+      }
+    } else {
+      reportError(config, t, e, null);
+    }
   }
 
   @Override

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagSingleObserver.java b/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagSingleObserver.java
@@ -15,6 +15,7 @@
  */
 package com.uber.rxdogtag;
 
+import static com.uber.rxdogtag.RxDogTag.createException;
 import static com.uber.rxdogtag.RxDogTag.guardedDelegateCall;
 import static com.uber.rxdogtag.RxDogTag.reportError;
 
@@ -67,7 +68,17 @@ public void onSuccess(T t) {
 
   @Override
   public void onError(Throwable e) {
-    reportError(config, t, e, null);
+    if (delegate instanceof RxDogTagErrorReceiver) {
+      if (delegate instanceof RxDogTagTaggedExceptionReceiver) {
+        delegate.onError(createException(config, t, e, null));
+      } else if (config.guardObserverCallbacks) {
+        guardedDelegateCall(e2 -> reportError(config, t, e2, "onError"), () -> delegate.onError(e));
+      } else {
+        delegate.onError(e);
+      }
+    } else {
+      reportError(config, t, e, null);
+    }
   }
 
   @Override

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagSubscriber.java b/rxdogtag/src/main/java/com/uber/rxdogtag/DogTagSubscriber.java
@@ -15,6 +15,7 @@
  */
 package com.uber.rxdogtag;
 
+import static com.uber.rxdogtag.RxDogTag.createException;
 import static com.uber.rxdogtag.RxDogTag.guardedDelegateCall;
 import static com.uber.rxdogtag.RxDogTag.reportError;
 
@@ -72,7 +73,17 @@ public void onNext(T t) {
 
   @Override
   public void onError(Throwable e) {
-    reportError(config, t, e, null);
+    if (delegate instanceof RxDogTagErrorReceiver) {
+      if (delegate instanceof RxDogTagTaggedExceptionReceiver) {
+        delegate.onError(createException(config, t, e, null));
+      } else if (config.guardObserverCallbacks) {
+        guardedDelegateCall(e2 -> reportError(config, t, e2, "onError"), () -> delegate.onError(e));
+      } else {
+        delegate.onError(e);
+      }
+    } else {
+      reportError(config, t, e, null);
+    }
   }
 
   @Override

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/RxDogTag.java b/rxdogtag/src/main/java/com/uber/rxdogtag/RxDogTag.java
@@ -103,16 +103,23 @@ public static void install() {
     new Builder().install();
   }
 
+  private static boolean shouldDecorate(Object observerToCheck) {
+    if (observerToCheck instanceof RxDogTagErrorReceiver) {
+      return true;
+    } else if (observerToCheck instanceof LambdaConsumerIntrospection) {
+      return !((LambdaConsumerIntrospection) observerToCheck).hasCustomOnError();
+    }
+    return false;
+  }
+
   private static synchronized void installWithBuilder(final Configuration config) {
     RxJavaPlugins.setOnObservableSubscribe(
         (observable, originalObserver) -> {
           for (ObserverHandler handler : config.observerHandlers) {
             Observer observerToCheck = handler.handle(observable, originalObserver);
-            if (observerToCheck instanceof LambdaConsumerIntrospection) {
-              if (!((LambdaConsumerIntrospection) observerToCheck).hasCustomOnError()) {
-                //noinspection unchecked
-                return new DogTagObserver(config, originalObserver);
-              }
+            if (shouldDecorate(observerToCheck)) {
+              //noinspection unchecked
+              return new DogTagObserver(config, originalObserver);
             }
           }
           return originalObserver;
@@ -121,11 +128,9 @@ private static synchronized void installWithBuilder(final Configuration config)
         (flowable, originalSubscriber) -> {
           for (ObserverHandler handler : config.observerHandlers) {
             Subscriber subscriberToCheck = handler.handle(flowable, originalSubscriber);
-            if (subscriberToCheck instanceof LambdaConsumerIntrospection) {
-              if (!((LambdaConsumerIntrospection) subscriberToCheck).hasCustomOnError()) {
-                //noinspection unchecked
-                return new DogTagSubscriber(config, originalSubscriber);
-              }
+            if (shouldDecorate(subscriberToCheck)) {
+              //noinspection unchecked
+              return new DogTagSubscriber(config, originalSubscriber);
             }
           }
           return originalSubscriber;
@@ -134,11 +139,9 @@ private static synchronized void installWithBuilder(final Configuration config)
         (single, originalObserver) -> {
           for (ObserverHandler handler : config.observerHandlers) {
             SingleObserver observerToCheck = handler.handle(single, originalObserver);
-            if (observerToCheck instanceof LambdaConsumerIntrospection) {
-              if (!((LambdaConsumerIntrospection) observerToCheck).hasCustomOnError()) {
-                //noinspection unchecked
-                return new DogTagSingleObserver(config, originalObserver);
-              }
+            if (shouldDecorate(observerToCheck)) {
+              //noinspection unchecked
+              return new DogTagSingleObserver(config, originalObserver);
             }
           }
           return originalObserver;
@@ -147,11 +150,9 @@ private static synchronized void installWithBuilder(final Configuration config)
         (maybe, originalObserver) -> {
           for (ObserverHandler handler : config.observerHandlers) {
             MaybeObserver observerToCheck = handler.handle(maybe, originalObserver);
-            if (observerToCheck instanceof LambdaConsumerIntrospection) {
-              if (!((LambdaConsumerIntrospection) observerToCheck).hasCustomOnError()) {
-                //noinspection unchecked
-                return new DogTagMaybeObserver(config, originalObserver);
-              }
+            if (shouldDecorate(observerToCheck)) {
+              //noinspection unchecked
+              return new DogTagMaybeObserver(config, originalObserver);
             }
           }
           return originalObserver;
@@ -160,10 +161,8 @@ private static synchronized void installWithBuilder(final Configuration config)
         (completable, originalObserver) -> {
           for (ObserverHandler handler : config.observerHandlers) {
             CompletableObserver observerToCheck = handler.handle(completable, originalObserver);
-            if (observerToCheck instanceof LambdaConsumerIntrospection) {
-              if (!((LambdaConsumerIntrospection) observerToCheck).hasCustomOnError()) {
-                return new DogTagCompletableObserver(config, originalObserver);
-              }
+            if (shouldDecorate(observerToCheck)) {
+              return new DogTagCompletableObserver(config, originalObserver);
             }
           }
           return originalObserver;
@@ -222,27 +221,28 @@ static void guardedDelegateCall(NonCheckingConsumer<Throwable> errorConsumer, Ru
     } catch (OnErrorNotImplementedException e) {
       Throwable cause = e.getCause();
       errorConsumer.accept(cause);
+    } catch (Throwable t) {
+      // This should only happen in cases where we're guarding a call to onError()
+      errorConsumer.accept(t);
     } finally {
       Thread.currentThread().setUncaughtExceptionHandler(h);
     }
   }
-
   /**
-   * Reports a new {@link OnErrorNotImplementedException} instance with an empty stacktrace and its
+   * Creates a new {@link OnErrorNotImplementedException} instance with an empty stacktrace and its
    * cause with a modified stacktrace. If the original cause is not an instance of
    * OnErrorNotImplementedException, a new one is created with the cause as its original cause. The
    * new modified stacktrace contains a line pointing to the inferred subscribe point, and then the
    * trace of the original {@code originalCause} (as the actual trace for the created trace is
    * irrelevant). The message of the exception is the message from the {@code originalCause}, if
    * present, and an empty string otherwise.
    *
-   * <p>Reporting is done via {@link RxJavaPlugins#onError(Throwable)}.
-   *
    * @param stackSource the source throwable to extract a stack element tag from.
    * @param originalCause the cause of the original error.
    * @param callbackType optional callback type of the original exception (onComplete, onNext, etc).
+   * @return the created exception.
    */
-  static void reportError(
+  static OnErrorNotImplementedException createException(
       Configuration config,
       Throwable stackSource,
       Throwable originalCause,
@@ -312,7 +312,23 @@ static void reportError(
       }
     }
     cause.setStackTrace(newTrace);
-    RxJavaPlugins.onError(error);
+    return error;
+  }
+
+  /**
+   * Shorthand for {@link #createException(Configuration, Throwable, Throwable, String)} + {@link
+   * RxJavaPlugins#onError(Throwable)}.
+   *
+   * @param stackSource the source throwable to extract a stack element tag from.
+   * @param originalCause the cause of the original error.
+   * @param callbackType optional callback type of the original exception (onComplete, onNext, etc).
+   */
+  static void reportError(
+      Configuration config,
+      Throwable stackSource,
+      Throwable originalCause,
+      @Nullable String callbackType) {
+    RxJavaPlugins.onError(createException(config, stackSource, originalCause, callbackType));
   }
 
   private static boolean containsAnyPackages(String input, Set<String> ignorablePackages) {

diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/RxDogTagErrorReceiver.java b/rxdogtag/src/main/java/com/uber/rxdogtag/RxDogTagErrorReceiver.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2019. Uber Technologies
+ *
+ * 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.uber.rxdogtag;
+
+import io.reactivex.annotations.NonNull;
+
+/**
+ * A marker type to indicate that RxDogTag's decorating observers should try the onError() of the
+ * delegate of the observer that implements this.
+ */
+public interface RxDogTagErrorReceiver {
+  /**
+   * Called once if the deferred computation 'throws' an exception.
+   *
+   * @param e the exception, not null.
+   */
+  void onError(@NonNull Throwable e);
+}
diff --git a/rxdogtag/src/main/java/com/uber/rxdogtag/RxDogTagTaggedExceptionReceiver.java b/rxdogtag/src/main/java/com/uber/rxdogtag/RxDogTagTaggedExceptionReceiver.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2019. Uber Technologies
+ *
+ * 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.uber.rxdogtag;
+
+import io.reactivex.exceptions.OnErrorNotImplementedException;
+
+/**
+ * A marker type to indicate that RxDogTag's should pass the decorated stacktrace to {@link
+ * #onError(Throwable)}. Note that this will always be tried directly, and no guarded delegate
+ * behavior will be attempted even if {@link RxDogTag.Builder#guardObserverCallbacks(boolean)} is
+ * enabled in configuration.
+ *
+ * <p><em>NOTE:</em> RxDogTag exceptions are always {@link OnErrorNotImplementedException
+ * OnErrorNotImplementedExceptions}, as these have special behavior as an escape hatch in RxJava
+ * internals. This exception will have no "cause" property if the original exception was not already
+ * an {@link OnErrorNotImplementedException}. If it was, which is unusual, it is reused with its
+ * original cause (if any) and has its stacktrace modified.
+ */
+public interface RxDogTagTaggedExceptionReceiver extends RxDogTagErrorReceiver {}