[executors/http] wrap upstream graphql errors in a GraphQLError instance

.changeset/dry-rice-design.md

@@ -0,0 +1,5 @@
+---
+"@graphql-tools/executor-http": patch
+---
+
+When proxying the requests to the HTTP executor, it should return \`GraphQLError\` instances in \`errors\` array

packages/executors/http/src/index.ts

@@ -259,6 +259,27 @@ export function buildHTTPExecutor(
                   ],
                 };
               }
+              if (Array.isArray(parsedResult.errors)) {
+                return {
+                  ...parsedResult,
+                  errors: parsedResult.errors.map(
+                    ({
+                      message,
+                      ...options
+                    }: {
+                      message: string;
+                      extensions: Record<string, unknown>;
+                    }) =>
+                      createGraphQLError(message, {
+                        ...options,
+                        extensions: {
+                          code: 'DOWNSTREAM_SERVICE_ERROR',
+                          ...(options.extensions || {}),
+                        },
+                      }),
+                  ),
+                };
+              }
               return parsedResult;
             } catch (e: any) {
               return {

packages/executors/http/tests/buildHTTPExecutor.test.ts

@@ -1,6 +1,6 @@
 import { createServer, Server } from 'http';
-import { parse } from 'graphql';
-import { createGraphQLError, ExecutionResult } from '@graphql-tools/utils';
+import { GraphQLError, parse } from 'graphql';
+import { createGraphQLError, ExecutionResult, isAsyncIterable } from '@graphql-tools/utils';
 import { ReadableStream, Request, Response } from '@whatwg-node/fetch';
 import { assertAsyncIterable } from '../../../loaders/url/tests/test-utils.js';
 import { buildHTTPExecutor } from '../src/index.js';
@@ -255,4 +255,29 @@ describe('buildHTTPExecutor', () => {
       }),
     ).toThrow('Executor was disposed. Aborting execution');
   });
+  it('should return return GraphqlError instances', async () => {
+    const executor = buildHTTPExecutor({
+      useGETForQueries: true,
+      fetch() {
+        return Response.json({ errors: [{ message: 'test error' }] });
+      },
+    });
+
+    const result = await executor({
+      document: parse(/* GraphQL */ `
+        query {
+          hello
+        }
+      `),
+    });
+
+    if (isAsyncIterable(result)) {
+      throw new Error('Expected result to be an ExecutionResult');
+    }
+
+    expect(result.errors?.[0]).toBeInstanceOf(GraphQLError);
+    expect(result.errors?.[0]?.extensions).toMatchObject({
+      code: 'DOWNSTREAM_SERVICE_ERROR',
+    });
+  });
 });