Refine handling of unresolved exceptions

Closes gh-352

Author: rstoyanchev

spring-graphql-docs/src/docs/asciidoc/index.adoc

@@ -514,30 +514,38 @@ added by <<server-interception, WebGraphQlInterceptor>> components.
 [[execution-exceptions]]
 === Exception Resolution
 
-GraphQL Java applications can register a `DataFetcherExceptionHandler` to decide how to
+A GraphQL Java application can register a `DataFetcherExceptionHandler` to decide how to
 represent exceptions from the data layer in the "errors" section of the GraphQL response.
 
 Spring for GraphQL has a built-in `DataFetcherExceptionHandler` that is configured for use
-by the <<execution-graphqlsource>> builder. It enables applications to register one or
-more Spring `DataFetcherExceptionResolver` components that are invoked sequentially
-until one resolves the `Exception` to a list of `graphql.GraphQLError` objects.
+by the default <<execution-graphqlsource>> builder. It allows applications to register
+one or more Spring `DataFetcherExceptionResolver` components that are invoked sequentially
+until one resolves the `Exception` to a (possibly empty) list of `graphql.GraphQLError`
+objects.
 
 `DataFetcherExceptionResolver` is an asynchronous contract. For most implementations, it
 would be sufficient to extend `DataFetcherExceptionResolverAdapter` and override
 one of its `resolveToSingleError` or `resolveToMultipleErrors` methods that
 resolve exceptions synchronously.
 
-A `GraphQLError` can be assigned an `graphql.ErrorClassification`. Spring for GraphQL
-defines an `ErrorType` enum with common, error classification categories:
+A `GraphQLError` can be assigned to a category via `graphql.ErrorClassification`.
+In Spring GraphQL, you can also assign via `ErrorType` which has the following common
+classifications that applications can use to categorize errors:
 
 - `BAD_REQUEST`
 - `UNAUTHORIZED`
 - `FORBIDDEN`
 - `NOT_FOUND`
 - `INTERNAL_ERROR`
 
-Applications can use this to classify errors. If an error remains unresolved, by
-default it is marked as `INTERNAL_ERROR`.
+If an exception remains unresolved, by default it is categorized as an `INTERNAL_ERROR`
+with a generic message that includes the category name and the `executionId` from
+`DataFetchingEnvironment`. The message is intentionally opaque to avoid leaking
+implementation details. Applications can use a `DataFetcherExceptionResolver` to customize
+error details.
+
+Unresolved exception are logged at ERROR level along with the `executionId` to correlate
+to the error sent to the client. Resolved exceptions are logged at DEBUG level.
 
 
 

spring-graphql/src/main/java/org/springframework/graphql/execution/ExceptionResolversExceptionHandler.java

@@ -35,7 +35,6 @@
 import reactor.util.context.ContextView;
 
 import org.springframework.util.Assert;
-import org.springframework.util.StringUtils;
 
 /**
  * {@link DataFetcherExceptionHandler} that invokes {@link DataFetcherExceptionResolver}'s
@@ -111,14 +110,14 @@ private void logResolvedException(Throwable ex, DataFetcherExceptionHandlerResul
 	}
 
 	private DataFetcherExceptionHandlerResult createInternalError(Throwable ex, DataFetchingEnvironment environment) {
+		ExecutionId executionId = environment.getExecutionId();
 		if (logger.isErrorEnabled()) {
-			ExecutionId id = environment.getExecutionId();
-			logger.error("Unresolved " + ex.getClass().getSimpleName() + ", executionId= " + id, ex);
+			logger.error("Unresolved " + ex.getClass().getSimpleName() + " for executionId " + executionId, ex);
 		}
 		return DataFetcherExceptionHandlerResult
 				.newResult(GraphqlErrorBuilder.newError(environment)
 						.errorType(ErrorType.INTERNAL_ERROR)
-						.message((StringUtils.hasText(ex.getMessage()) ? ex.getMessage() : ex.getClass().getSimpleName()))
+						.message(ErrorType.INTERNAL_ERROR + " for " + executionId)
 						.build())
 				.build();
 	}

spring-graphql/src/test/java/org/springframework/graphql/execution/ExceptionResolversExceptionHandlerTests.java

@@ -27,8 +27,8 @@
 import reactor.util.context.Context;
 import reactor.util.context.ContextView;
 
-import org.springframework.graphql.ResponseHelper;
 import org.springframework.graphql.GraphQlSetup;
+import org.springframework.graphql.ResponseHelper;
 import org.springframework.graphql.TestThreadLocalAccessor;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -126,7 +126,7 @@ void unresolvedException() throws Exception {
 
 		ResponseHelper response = ResponseHelper.forResult(result);
 		assertThat(response.errorCount()).isEqualTo(1);
-		assertThat(response.error(0).message()).isEqualTo("Invalid greeting");
+		assertThat(response.error(0).message()).startsWith("INTERNAL_ERROR for ");
 		assertThat(response.error(0).errorType()).isEqualTo("INTERNAL_ERROR");
 
 		String greeting = response.rawValue("greeting");