Include causal status details in higher-level statuses

core/src/main/java/io/grpc/internal/GrpcUtil.java

@@ -821,6 +821,31 @@ public static Status replaceInappropriateControlPlaneStatus(Status status) {
             + status.getDescription()).withCause(status.getCause()) : status;
   }
 
+  /**
+   * Returns a "clean" representation of a status code and description (not cause) like
+   * "UNAVAILABLE: The description". Should be similar to Status.formatThrowableMessage().
+   */
+  public static String statusToPrettyString(Status status) {
+    if (status.getDescription() == null) {
+      return status.getCode().toString();
+    } else {
+      return status.getCode() + ": " + status.getDescription();
+    }
+  }
+
+  /**
+   * Create a status with contextual information, propagating details from a non-null status that
+   * contributed to the failure. For example, if UNAVAILABLE, "Couldn't load bar", and status
+   * "FAILED_PRECONDITION: Foo missing" were passed as arguments, then this method would produce the
+   * status "UNAVAILABLE: Couldn't load bar: FAILED_PRECONDITION: Foo missing" with a cause if the
+   * passed status had a cause.
+   */
+  public static Status statusWithDetails(Status.Code code, String description, Status causeStatus) {
+    return code.toStatus()
+        .withDescription(description + ": " + statusToPrettyString(causeStatus))
+        .withCause(causeStatus.getCause());
+  }
+
   /**
    * Checks whether the given item exists in the iterable.  This is copied from Guava Collect's
    * {@code Iterables.contains()} because Guava Collect is not Android-friendly thus core can't

core/src/main/java/io/grpc/internal/RetriableStream.java

@@ -938,9 +938,8 @@ public void run() {
           && localOnlyTransparentRetries.incrementAndGet() > 1_000) {
         commitAndRun(substream);
         if (state.winningSubstream == substream) {
-          Status tooManyTransparentRetries = Status.INTERNAL
-              .withDescription("Too many transparent retries. Might be a bug in gRPC")
-              .withCause(status.asRuntimeException());
+          Status tooManyTransparentRetries = GrpcUtil.statusWithDetails(
+              Status.Code.INTERNAL, "Too many transparent retries. Might be a bug in gRPC", status);
           safeCloseMasterListener(tooManyTransparentRetries, rpcProgress, trailers);
         }
         return;

opentelemetry/src/main/java/io/grpc/opentelemetry/OpenTelemetryTracingModule.java

@@ -36,6 +36,7 @@
 import io.grpc.ServerCallHandler;
 import io.grpc.ServerInterceptor;
 import io.grpc.ServerStreamTracer;
+import io.grpc.internal.GrpcUtil;
 import io.grpc.opentelemetry.internal.OpenTelemetryConstants;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.common.AttributesBuilder;
@@ -463,19 +464,11 @@ private void recordInboundMessageSize(Span span, int seqNo, long bytes) {
     span.addEvent("Inbound message", attributesBuilder.build());
   }
 
-  private String generateErrorStatusDescription(io.grpc.Status status) {
-    if (status.getDescription() != null) {
-      return status.getCode() + ": " + status.getDescription();
-    } else {
-      return status.getCode().toString();
-    }
-  }
-
   private void endSpanWithStatus(Span span, io.grpc.Status status) {
     if (status.isOk()) {
       span.setStatus(StatusCode.OK);
     } else {
-      span.setStatus(StatusCode.ERROR, generateErrorStatusDescription(status));
+      span.setStatus(StatusCode.ERROR, GrpcUtil.statusToPrettyString(status));
     }
     span.end();
   }

util/src/main/java/io/grpc/util/OutlierDetectionLoadBalancerProvider.java

@@ -23,6 +23,7 @@
 import io.grpc.LoadBalancerProvider;
 import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
+import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.JsonUtil;
 import io.grpc.util.OutlierDetectionLoadBalancer.OutlierDetectionLoadBalancerConfig;
 import io.grpc.util.OutlierDetectionLoadBalancer.OutlierDetectionLoadBalancerConfig.FailurePercentageEjection;
@@ -148,9 +149,10 @@ private ConfigOrError parseLoadBalancingPolicyConfigInternal(Map<String, ?> rawC
     ConfigOrError childConfig = GracefulSwitchLoadBalancer.parseLoadBalancingPolicyConfig(
         JsonUtil.getListOfObjects(rawConfig, "childPolicy"));
     if (childConfig.getError() != null) {
-      return ConfigOrError.fromError(Status.INTERNAL
-          .withDescription("Failed to parse child in outlier_detection_experimental: " + rawConfig)
-          .withCause(childConfig.getError().asRuntimeException()));
+      return ConfigOrError.fromError(GrpcUtil.statusWithDetails(
+          Status.Code.UNAVAILABLE,
+          "Failed to parse child in outlier_detection_experimental",
+          childConfig.getError()));
     }
     configBuilder.setChildConfig(childConfig.getConfig());
 

xds/src/main/java/io/grpc/xds/WeightedTargetLoadBalancerProvider.java

@@ -25,6 +25,7 @@
 import io.grpc.LoadBalancerRegistry;
 import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
+import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.JsonUtil;
 import io.grpc.util.GracefulSwitchLoadBalancer;
 import java.util.LinkedHashMap;
@@ -99,9 +100,10 @@ public ConfigOrError parseLoadBalancingPolicyConfig(Map<String, ?> rawConfig) {
         ConfigOrError childConfig = GracefulSwitchLoadBalancer.parseLoadBalancingPolicyConfig(
             JsonUtil.getListOfObjects(rawWeightedTarget, "childPolicy"), lbRegistry);
         if (childConfig.getError() != null) {
-          return ConfigOrError.fromError(Status.INTERNAL
-              .withDescription("Could not parse weighted_target's child policy:" + name)
-              .withCause(childConfig.getError().asRuntimeException()));
+          return ConfigOrError.fromError(GrpcUtil.statusWithDetails(
+              Status.Code.INTERNAL,
+              "Could not parse weighted_target's child policy: " + name,
+              childConfig.getError()));
         }
         parsedChildConfigs.put(name, new WeightedPolicySelection(weight, childConfig.getConfig()));
       }

xds/src/main/java/io/grpc/xds/WrrLocalityLoadBalancerProvider.java

@@ -23,6 +23,7 @@
 import io.grpc.LoadBalancerRegistry;
 import io.grpc.NameResolver.ConfigOrError;
 import io.grpc.Status;
+import io.grpc.internal.GrpcUtil;
 import io.grpc.internal.JsonUtil;
 import io.grpc.util.GracefulSwitchLoadBalancer;
 import io.grpc.xds.WrrLocalityLoadBalancer.WrrLocalityConfig;
@@ -62,9 +63,10 @@ public ConfigOrError parseLoadBalancingPolicyConfig(Map<String, ?> rawConfig) {
       ConfigOrError childConfig = GracefulSwitchLoadBalancer.parseLoadBalancingPolicyConfig(
           JsonUtil.getListOfObjects(rawConfig, "childPolicy"));
       if (childConfig.getError() != null) {
-        return ConfigOrError.fromError(Status.INTERNAL
-            .withDescription("Failed to parse child policy in wrr_locality LB policy: " + rawConfig)
-            .withCause(childConfig.getError().asRuntimeException()));
+        return ConfigOrError.fromError(GrpcUtil.statusWithDetails(
+            Status.Code.INTERNAL,
+            "Failed to parse child policy in wrr_locality LB policy",
+            childConfig.getError()));
       }
       return ConfigOrError.fromConfig(new WrrLocalityConfig(childConfig.getConfig()));
     } catch (RuntimeException e) {