From 3d164ea16c17d271f6fa9e5ad8f013623eec23a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavol=20Luk=C4=8Da?= <pavol.lukca@gmail.com>
Date: Wed, 12 Jun 2024 20:08:48 +0200
Subject: [PATCH] fix: graphQLErrors in Error Link if networkError.result is an
 empty string (#11329)

---
 .changeset/loud-hounds-heal.md    |  5 +++++
 src/link/error/__tests__/index.ts | 34 +++++++++++++++++++++++++++++++
 src/link/error/index.ts           |  7 ++++---
 3 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 .changeset/loud-hounds-heal.md

diff --git a/.changeset/loud-hounds-heal.md b/.changeset/loud-hounds-heal.md
new file mode 100644
index 00000000000..f80a0a34105
--- /dev/null
+++ b/.changeset/loud-hounds-heal.md
@@ -0,0 +1,5 @@
+---
+"@apollo/client": patch
+---
+
+Fix graphQLErrors in Error Link if networkError.result is an empty string
diff --git a/src/link/error/__tests__/index.ts b/src/link/error/__tests__/index.ts
index a6189ee3b87..5e886ff58d3 100644
--- a/src/link/error/__tests__/index.ts
+++ b/src/link/error/__tests__/index.ts
@@ -145,6 +145,40 @@ describe("error handling", () => {
       });
     }
   );
+  itAsync(
+    "sets graphQLErrors to undefined if networkError.result is an empty string",
+    (resolve, reject) => {
+      const query = gql`
+        query Foo {
+          foo {
+            bar
+          }
+        }
+      `;
+
+      let called: boolean;
+      const errorLink = onError(({ graphQLErrors }) => {
+        expect(graphQLErrors).toBeUndefined();
+        called = true;
+      });
+
+      const mockLink = new ApolloLink((operation) => {
+        return new Observable((obs) => {
+          const response = { status: 500, ok: false } as Response;
+          throwServerError(response, "", "app is crashing");
+        });
+      });
+
+      const link = errorLink.concat(mockLink);
+
+      execute(link, { query }).subscribe({
+        error: (e) => {
+          expect(called).toBe(true);
+          resolve();
+        },
+      });
+    }
+  );
   itAsync("completes if no errors", (resolve, reject) => {
     const query = gql`
       {
diff --git a/src/link/error/index.ts b/src/link/error/index.ts
index 7122ff792e8..00b0701ab6f 100644
--- a/src/link/error/index.ts
+++ b/src/link/error/index.ts
@@ -60,9 +60,10 @@ export function onError(errorHandler: ErrorHandler): ApolloLink {
               networkError,
               //Network errors can return GraphQL errors on for example a 403
               graphQLErrors:
-                networkError &&
-                networkError.result &&
-                networkError.result.errors,
+                (networkError &&
+                  networkError.result &&
+                  networkError.result.errors) ||
+                void 0,
               forward,
             });
             if (retriedResult) {