fix: resolve DirectPath validation regression and add misconfig tests\n\n- Fixed logic in validateDirectPathState to ensure credential and GCE checks are always performed when DirectPath is enabled.\n- Added explicit warnings for DirectPath misconfigurations (xDS mismatch).\n- Added regression tests in InstantiatingGrpcChannelProviderTest.\n\n[Generated-by: AI]

Author: nidhiii-27

sdk-platform-java/gax-java/gax-grpc/src/main/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProvider.java

@@ -397,7 +397,7 @@ public TransportChannel getTransportChannel() throws IOException {
     } else if (needsEndpoint()) {
       throw new IllegalStateException("getTransportChannel() called when needsEndpoint() is true");
     } else {
-      logDirectPathMisconfig();
+      validateDirectPathState();
       return createChannel();
     }
   }
@@ -454,15 +454,11 @@ public boolean isDirectPathXdsEnabled() {
   // This method should be called once per client initialization, hence can not be called in the
   // builder or createSingleChannel, only in getTransportChannel which creates the first channel
   // for a client.
-  private void logDirectPathMisconfig() {
-    if (!isDirectPathXdsEnabled()) {
-      return;
-    }
-
+  @InternalApi
+  public void validateDirectPathState() {
     Level level = isOnComputeEngine() ? Level.WARNING : Level.FINE;
 
     if (!isDirectPathEnabled()) {
-      // This misconfiguration occurs when Direct Path xDS is enabled, but Direct Path is not
       // Direct Path xDS can be enabled two ways: via environment variable or via builder.
       // Case 1: Direct Path is only enabled via xDS env var. We will _warn_ the user that this is
       // a misconfiguration if they intended to set the env var.
@@ -483,15 +479,21 @@ else if (isDirectPathXdsEnabledViaBuilderOption()) {
             "DirectPath is misconfigured. The DirectPath XDS option was set, but the attemptDirectPath option was not. Please set both the attemptDirectPath and attemptDirectPathXds options.");
       }
     } else {
-      // Case 3: credential is not correctly set
+      // Case 3: DirectPath is enabled, but xDS is not.
+      if (!isDirectPathXdsEnabled()) {
+        LOG.log(
+            level,
+            "DirectPath is enabled, but DirectPath xDS is not. Please note that DirectPath will soon require xDS to be enabled. Please set the attemptDirectPathXds option.");
+      }
+      // Case 4: credential is not correctly set
       if (!isCredentialDirectPathCompatible()) {
         LOG.log(
             level,
             "DirectPath is misconfigured. Please make sure the credential is an instance of "
                 + ComputeEngineCredentials.class.getName()
                 + " .");
       }
-      // Case 4: not running on GCE
+      // Case 5: not running on GCE
       if (!isOnComputeEngine() && !isAttemptDirectPathXdsOverInterconnect()) {
         LOG.log(
             level,

sdk-platform-java/gax-java/gax-grpc/src/test/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProviderTest.java

@@ -1583,6 +1583,61 @@ private static String extractTargetFromChannelBuilder(ManagedChannelBuilder<?> c
     return channelBuilder.toString();
   }
 
+  @Test
+  void testLogDirectPathMisconfigXdsSetDirectPathNotSet() throws Exception {
+    FakeLogHandler logHandler = new FakeLogHandler();
+    InstantiatingGrpcChannelProvider.LOG.setLevel(Level.FINE);
+    InstantiatingGrpcChannelProvider.LOG.addHandler(logHandler);
+    InstantiatingGrpcChannelProvider provider =
+        InstantiatingGrpcChannelProvider.newBuilder()
+            .setAttemptDirectPathXds()
+            .setAttemptDirectPath(false)
+            .setHeaderProvider(
+                mock(HeaderProvider.class, Mockito.withSettings().withoutAnnotations()))
+            .setExecutor(mock(Executor.class, Mockito.withSettings().withoutAnnotations()))
+            .setEndpoint(DEFAULT_ENDPOINT)
+            .setCertificateBasedAccess(certificateBasedAccess)
+            .build();
+
+    try {
+      provider.getTransportChannel();
+    } catch (Exception e) {
+      // ignore
+    }
+
+    assertThat(logHandler.getAllMessages())
+        .contains(
+            "DirectPath is misconfigured. The DirectPath XDS option was set, but the attemptDirectPath option was not. Please set both the attemptDirectPath and attemptDirectPathXds options.");
+    InstantiatingGrpcChannelProvider.LOG.removeHandler(logHandler);
+  }
+
+  @Test
+  void testLogDirectPathMisconfigDirectPathSetXdsNotSet() throws Exception {
+    FakeLogHandler logHandler = new FakeLogHandler();
+    InstantiatingGrpcChannelProvider.LOG.setLevel(Level.FINE);
+    InstantiatingGrpcChannelProvider.LOG.addHandler(logHandler);
+    InstantiatingGrpcChannelProvider provider =
+        InstantiatingGrpcChannelProvider.newBuilder()
+            .setAttemptDirectPath(true)
+            .setHeaderProvider(
+                mock(HeaderProvider.class, Mockito.withSettings().withoutAnnotations()))
+            .setExecutor(mock(Executor.class, Mockito.withSettings().withoutAnnotations()))
+            .setEndpoint(DEFAULT_ENDPOINT)
+            .setCertificateBasedAccess(certificateBasedAccess)
+            .build();
+
+    try {
+      provider.getTransportChannel();
+    } catch (Exception e) {
+      // ignore
+    }
+
+    assertThat(logHandler.getAllMessages())
+        .contains(
+            "DirectPath is enabled, but DirectPath xDS is not. Please note that DirectPath will soon require xDS to be enabled. Please set the attemptDirectPathXds option.");
+    InstantiatingGrpcChannelProvider.LOG.removeHandler(logHandler);
+  }
+
   private static class FakeLogHandler extends Handler {
 
     List<LogRecord> records = new ArrayList<>();