Fix context propagation in AsyncProgramImpl to preserve resolved attributes.

runtime/src/main/java/dev/cel/runtime/async/AsyncProgramImpl.java

@@ -160,7 +160,7 @@ private ListenableFuture<Object> evalPass(
             new CelEvaluationException("Max Evaluation iterations exceeded: " + iteration));
       }
       return resolveAndReevaluate(
-          (CelUnknownSet) result, startingUnknownContext, resolvableAttributePatterns, iteration);
+          (CelUnknownSet) result, ctx, resolvableAttributePatterns, iteration);
     }
 
     return immediateFuture(result);

runtime/src/test/java/dev/cel/runtime/async/CelAsyncRuntimeImplTest.java

@@ -103,6 +103,56 @@ public void asyncProgram_basicUnknownResolution() throws Exception {
     assertThat(result).isEqualTo(true);
   }
 
+  @Test
+  public void asyncProgram_sequentialUnknownResolution() throws Exception {
+    // Arrange
+    CelUnknownAttributeValueResolver resolveName =
+        CelUnknownAttributeValueResolver.fromResolver(
+            (attr) -> {
+              Thread.sleep(500);
+              return attr.toString();
+            });
+    Cel cel =
+        CelFactory.standardCelBuilder()
+            .setOptions(CelOptions.current().enableUnknownTracking(true).build())
+            .addMessageTypes(TestAllTypes.getDescriptor())
+            .addVar("com.google.var1", SimpleType.BOOL)
+            .addVar("com.google.var2", SimpleType.STRING)
+            .addVar("com.google.var3", SimpleType.STRING)
+            .setResultType(SimpleType.STRING)
+            .setContainer(CelContainer.ofName("com.google"))
+            .build();
+
+    CelAsyncRuntime asyncRuntime =
+        CelAsyncRuntimeFactory.defaultAsyncRuntime()
+            .setRuntime(cel)
+            .setExecutorService(newDirectExecutorService())
+            .build();
+
+    CelAbstractSyntaxTree ast =
+        cel.compile(
+                "var1 ? var2 : var3")
+            .getAst();
+
+    AsyncProgram program = asyncRuntime.createProgram(ast);
+
+    // Act
+    ListenableFuture<Object> future =
+        program.evaluateToCompletion(
+            CelResolvableAttributePattern.of(
+                CelAttributePattern.fromQualifiedIdentifier("com.google.var1"),
+                CelUnknownAttributeValueResolver.fromResolver(unused -> true)),
+            CelResolvableAttributePattern.of(
+                CelAttributePattern.fromQualifiedIdentifier("com.google.var2"), resolveName),
+            CelResolvableAttributePattern.of(
+                CelAttributePattern.fromQualifiedIdentifier("com.google.var3"), resolveName));
+    Object result = future.get(2, SECONDS);
+
+    // Assert
+    assertThat(result).isInstanceOf(String.class);
+    assertThat(result).isEqualTo("com.google.var2");
+  }
+
   @Test
   public void asyncProgram_basicAsyncResolver() throws Exception {
     // Arrange