fix(openai): cancel oversized Codex image streams

vincentkoc · vincentkoc · commit 13be16d69987 · 2026-06-19T08:07:17.000+02:00
diff --git a/extensions/openai/image-generation-provider.test.ts b/extensions/openai/image-generation-provider.test.ts
@@ -1001,6 +1001,42 @@ describe("openai image generation provider", () => {
     });
   });
 
+  it("cancels oversized Codex OAuth image response streams", async () => {
+    mockCodexAuthOnly();
+    let canceled = false;
+    let chunkSent = false;
+    const release = vi.fn(async () => {});
+    const stream = new ReadableStream<Uint8Array>({
+      pull(controller) {
+        if (chunkSent) {
+          return;
+        }
+        chunkSent = true;
+        controller.enqueue(new Uint8Array(64 * 1024 * 1024 + 1));
+      },
+      cancel() {
+        canceled = true;
+      },
+    });
+    postJsonRequestMock.mockResolvedValue({
+      response: new Response(stream),
+      release,
+    });
+
+    const provider = buildOpenAIImageGenerationProvider();
+    await expect(
+      provider.generateImage({
+        provider: "openai",
+        model: "gpt-image-2",
+        prompt: "Draw an oversized Codex lighthouse",
+        cfg: {},
+        authStore: createCodexOAuthAuthStore(),
+      }),
+    ).rejects.toThrow("OpenAI Codex image generation response exceeded size limit");
+    expect(canceled).toBe(true);
+    expect(release).toHaveBeenCalledTimes(1);
+  });
+
   it("does not treat Codex API key profiles as configured Codex OAuth image auth", async () => {
     mockGeneratedPngResponse();
     resolveApiKeyForProviderMock.mockImplementation(async (params?: { provider?: string }) => {
diff --git a/extensions/openai/image-generation-provider.ts b/extensions/openai/image-generation-provider.ts
@@ -506,6 +506,7 @@ async function readResponseBodyText(response: Response): Promise<string> {
       if (value) {
         byteLength += value.byteLength;
         if (byteLength > MAX_CODEX_IMAGE_SSE_BYTES) {
+          await reader.cancel().catch(() => undefined);
           throw new Error("OpenAI Codex image generation response exceeded size limit");
         }
         chunks.push(decoder.decode(value, { stream: !done }));

Original file line number	Diff line number	Diff line change
`@@ -506,6 +506,7 @@ async function readResponseBodyText(response: Response): Promise<string> {`
`506`	`506`	`if (value) {`
`507`	`507`	`byteLength += value.byteLength;`
`508`	`508`	`if (byteLength > MAX_CODEX_IMAGE_SSE_BYTES) {`
	`509`	`+ await reader.cancel().catch(() => undefined);`
`509`	`510`	`throw new Error("OpenAI Codex image generation response exceeded size limit");`
`510`	`511`	`}`
`511`	`512`	`chunks.push(decoder.decode(value, { stream: !done }));`