Fix nullness errors in SimpleDoFnRunner and DoFnInvoker

runners/core-java/src/main/java/org/apache/beam/runners/core/LateDataUtils.java

@@ -25,6 +25,7 @@
 import org.apache.beam.sdk.values.WindowingStrategy;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.FluentIterable;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.Iterables;
+import org.checkerframework.dataflow.qual.Pure;
 import org.joda.time.Duration;
 import org.joda.time.Instant;
 
@@ -41,6 +42,7 @@ private LateDataUtils() {}
    * Return when {@code window} should be garbage collected. If the window's expiration time is on
    * or after the end of the global window, it will be truncated to the end of the global window.
    */
+  @Pure
   public static Instant garbageCollectionTime(
       BoundedWindow window, WindowingStrategy windowingStrategy) {
     return garbageCollectionTime(window, windowingStrategy.getAllowedLateness());
@@ -50,6 +52,7 @@ public static Instant garbageCollectionTime(
    * Return when {@code window} should be garbage collected. If the window's expiration time is on
    * or after the end of the global window, it will be truncated to the end of the global window.
    */
+  @Pure
   public static Instant garbageCollectionTime(BoundedWindow window, Duration allowedLateness) {
 
     // If the end of the window + allowed lateness is beyond the "end of time" aka the end of the

runners/core-java/src/main/java/org/apache/beam/runners/core/OutputAndTimeBoundedSplittableProcessElementInvoker.java

@@ -387,12 +387,12 @@ public PaneInfo pane() {
     }
 
     @Override
-    public String currentRecordId() {
+    public @Nullable String currentRecordId() {
       return element.getRecordId();
     }
 
     @Override
-    public Long currentRecordOffset() {
+    public @Nullable Long currentRecordOffset() {
       return element.getRecordOffset();
     }
 

runners/core-java/src/main/java/org/apache/beam/runners/core/SideInputReader.java

@@ -19,25 +19,22 @@
 
 import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
 import org.apache.beam.sdk.values.PCollectionView;
-import org.checkerframework.checker.nullness.qual.Nullable;
+import org.checkerframework.dataflow.qual.Pure;
 
 /**
  * The interface to objects that provide side inputs. Particular implementations may read a side
  * input directly or use appropriate sorts of caching, etc.
  */
 public interface SideInputReader {
-  /**
-   * Returns the value of the given {@link PCollectionView} for the given {@link BoundedWindow}.
-   *
-   * <p>It is valid for a side input to be {@code null}. It is <i>not</i> valid for this to return
-   * {@code null} for any other reason.
-   */
-  @Nullable
+  /** Returns the value of the given {@link PCollectionView} for the given {@link BoundedWindow}. */
+  @Pure
   <T> T get(PCollectionView<T> view, BoundedWindow window);
 
   /** Returns true if the given {@link PCollectionView} is valid for this reader. */
+  @Pure
   <T> boolean contains(PCollectionView<T> view);
 
   /** Returns true if there are no side inputs in this reader. */
+  @Pure
   boolean isEmpty();
 }