Simplification: Context.root() is always empty (#8580)

mcculls · web-flow · commit 6a2404487fbf · 2025-03-18T11:42:03.000Z
We haven't needed a non-empty root context, and collapsing these concepts together simplifies the code.
diff --git a/components/context/src/main/java/datadog/context/Context.java b/components/context/src/main/java/datadog/context/Context.java
@@ -36,22 +36,13 @@
  * @see ContextKey
  */
 public interface Context {
-  /**
-   * Returns the empty context.
-   *
-   * @return the context containing no values at all.
-   */
-  static Context empty() {
-    return EmptyContext.INSTANCE;
-  }
-
   /**
    * Returns the root context.
    *
    * @return the initial local context that all contexts extend.
    */
   static Context root() {
-    return manager().root();
+    return EmptyContext.INSTANCE;
   }
 
   /**
diff --git a/components/context/src/main/java/datadog/context/ContextManager.java b/components/context/src/main/java/datadog/context/ContextManager.java
@@ -2,17 +2,10 @@
 
 /** Manages context across execution units. */
 public interface ContextManager {
-  /**
-   * Returns the root context.
-   *
-   * @return the initial local context that all contexts extend.
-   */
-  Context root();
-
   /**
    * Returns the context attached to the current execution unit.
    *
-   * @return the attached context; {@link #root()} if there is none.
+   * @return the attached context; {@link Context#root()} if there is none.
    */
   Context current();
 
@@ -28,7 +21,7 @@ public interface ContextManager {
    * Swaps the given context with the one attached to current execution unit.
    *
    * @param context the context to swap.
-   * @return the previously attached context; {@link #root()} if there was none.
+   * @return the previously attached context; {@link Context#root()} if there was none.
    */
   Context swap(Context context);
 
diff --git a/components/context/src/main/java/datadog/context/ThreadLocalContextManager.java b/components/context/src/main/java/datadog/context/ThreadLocalContextManager.java
@@ -5,11 +5,6 @@ final class ThreadLocalContextManager implements ContextManager {
   private static final ThreadLocal<Context[]> CURRENT_HOLDER =
       ThreadLocal.withInitial(() -> new Context[] {EmptyContext.INSTANCE});
 
-  @Override
-  public Context root() {
-    return EmptyContext.INSTANCE;
-  }
-
   @Override
   public Context current() {
     return CURRENT_HOLDER.get()[0];
diff --git a/components/context/src/test/java/datadog/context/ContextProviderForkedTest.java b/components/context/src/test/java/datadog/context/ContextProviderForkedTest.java
@@ -42,11 +42,6 @@ void testCustomManager() {
     // register a NOOP context manager
     ContextManager.register(
         new ContextManager() {
-          @Override
-          public Context root() {
-            return EmptyContext.INSTANCE;
-          }
-
           @Override
           public Context current() {
             return root();
diff --git a/components/context/src/test/java/datadog/context/ContextTest.java b/components/context/src/test/java/datadog/context/ContextTest.java
@@ -1,6 +1,5 @@
 package datadog.context;
 
-import static datadog.context.Context.empty;
 import static datadog.context.Context.root;
 import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -22,17 +21,6 @@ class ContextTest {
   static final ContextKey<Float> FLOAT_KEY = ContextKey.named("float-key");
   static final ContextKey<Long> LONG_KEY = ContextKey.named("long-key");
 
-  @Test
-  void testEmpty() {
-    // Test empty is always the same
-    Context empty = empty();
-    assertEquals(empty, empty(), "Empty context should be consistent");
-    // Test empty is not mutated
-    String stringValue = "value";
-    empty.with(STRING_KEY, stringValue);
-    assertEquals(empty, empty(), "Empty context should be immutable");
-  }
-
   @Test
   void testRoot() {
     // Test root is always the same
