Merge pull request #28 from technoir42/fix_callback_npe

Don't crash in stopWork if registerIdleTransitionCallback hasn't been called yet
square · May 19, 2020 · a3fed12 · a3fed12
2 parents 1b31ca5 + 62bd790
commit a3fed12
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Showing 4 changed files with 20 additions and 4 deletions.
diff --git a/rx1-idler/src/main/java/com/squareup/rx/idler/DelegatingIdlingResourceScheduler.java b/rx1-idler/src/main/java/com/squareup/rx/idler/DelegatingIdlingResourceScheduler.java
@@ -1,5 +1,6 @@
 package com.squareup.rx.idler;
 
+import androidx.annotation.Nullable;
 import androidx.annotation.RestrictTo;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -16,7 +17,7 @@ final class DelegatingIdlingResourceScheduler extends IdlingResourceScheduler {
   private final Scheduler delegate;
   private final String name;
   private final AtomicInteger work = new AtomicInteger();
-  private ResourceCallback callback;
+  @Nullable private ResourceCallback callback;
 
   DelegatingIdlingResourceScheduler(Scheduler delegate, String name) {
     this.delegate = delegate;
@@ -96,7 +97,7 @@ void startWork() {
   }
 
   void stopWork() {
-    if (work.decrementAndGet() == 0) {
+    if (work.decrementAndGet() == 0 && callback != null) {
       callback.onTransitionToIdle();
     }
   }

diff --git a/rx1-idler/src/test/java/com/squareup/rx/idler/DelegatingIdlingResourceSchedulerTest.java b/rx1-idler/src/test/java/com/squareup/rx/idler/DelegatingIdlingResourceSchedulerTest.java
@@ -120,6 +120,13 @@ public final class DelegatingIdlingResourceSchedulerTest {
     assertIdle(0);
   }
 
+  @Test public void finishingWorkWithoutRegisteredCallbackDoesNotCrash() {
+    IdlingResourceScheduler scheduler = RxIdler.wrap(delegate, "Bob");
+    Scheduler.Worker worker = scheduler.createWorker();
+    worker.schedule(new CountingAction());
+    delegate.triggerActions();
+  }
+
   private void assertBusy() {
     assertFalse(scheduler.isIdleNow());
   }

diff --git a/rx2-idler/src/main/java/com/squareup/rx2/idler/DelegatingIdlingResourceScheduler.java b/rx2-idler/src/main/java/com/squareup/rx2/idler/DelegatingIdlingResourceScheduler.java
@@ -1,5 +1,6 @@
 package com.squareup.rx2.idler;
 
+import androidx.annotation.Nullable;
 import androidx.annotation.RestrictTo;
 import io.reactivex.Scheduler;
 import io.reactivex.disposables.CompositeDisposable;
@@ -15,7 +16,7 @@ final class DelegatingIdlingResourceScheduler extends IdlingResourceScheduler {
   private final Scheduler delegate;
   private final String name;
   private final AtomicInteger work = new AtomicInteger();
-  private ResourceCallback callback;
+  @Nullable private ResourceCallback callback;
 
   DelegatingIdlingResourceScheduler(Scheduler delegate, String name) {
     this.delegate = delegate;
@@ -92,7 +93,7 @@ void startWork() {
   }
 
   void stopWork() {
-    if (work.decrementAndGet() == 0) {
+    if (work.decrementAndGet() == 0 && callback != null) {
       callback.onTransitionToIdle();
     }
   }

diff --git a/rx2-idler/src/test/java/com/squareup/rx2/idler/DelegatingIdlingResourceSchedulerTest.java b/rx2-idler/src/test/java/com/squareup/rx2/idler/DelegatingIdlingResourceSchedulerTest.java
@@ -119,6 +119,13 @@ public final class DelegatingIdlingResourceSchedulerTest {
     assertIdle(0);
   }
 
+  @Test public void finishingWorkWithoutRegisteredCallbackDoesNotCrash() {
+    IdlingResourceScheduler scheduler = Rx2Idler.wrap(delegate, "Bob");
+    Scheduler.Worker worker = scheduler.createWorker();
+    worker.schedule(new CountingRunnable());
+    delegate.triggerActions();
+  }
+
   private void assertBusy() {
     assertFalse(scheduler.isIdleNow());
   }