[Bug]: Firefox 146 in v1.58.0 can't read response json body from GET requests

[tarungunampalli1]

Version

1.58.0

Steps to reproduce

1. Clone https://github.com/tarungunampalli1/playwright-minimal-repro
2. run yarn test or npm test
3. See Error: response.json: Protocol error (Network.getResponseBody): Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIStreamListener.onDataAvailable]

Expected behavior

I expect to see the response body parsed into JSON

Actual behavior

Trying to get response.json() fails with an error

Additional context

NOTE!!!
This is a duplicate of #39020 (comment). The previous issue was closed prematurely and the repro included in the response did not include the actual failure case. I'm opening a duplicate issue as closed issues aren't monitored.

Environment

System:
    OS: macOS 26.2
    CPU: (12) arm64 Apple M3 Pro
    Memory: 1.14 GB / 36.00 GB
  Binaries:
    Node: 23.11.0 - /Users/tarun.gunampalli/.proto/tools/node/23.11.0/bin/node
    Yarn: 4.5.0 - /Users/tarun.gunampalli/.proto/shims/yarn
    npm: 10.9.2 - /Users/tarun.gunampalli/.proto/tools/node/23.11.0/bin/npm
    pnpm: 9.15.3 - /Users/tarun.gunampalli/.nvm/versions/node/v20.20.0/bin/pnpm
  IDEs:
    VSCode: 1.108.2 - /usr/local/bin/code
    Cursor: 2.0.69 - /usr/local/bin/cursor
    Claude Code: 2.0.76 - /Users/tarun.gunampalli/.local/bin/claude
    opencode: 1.1.40 - /Users/tarun.gunampalli/.opencode/bin/opencode
  Languages:
    Bash: 3.2.57 - /bin/bash
  npmPackages:
    @playwright/test: ^1.58.0 => 1.58.0 

This was also reproducible on my repo CI, which runs on linux

[stephen-t-scheme]

Since going to 1.58.0, I have experienced similar in Firefox 146.0.1, but when calling await response.text(). I am receiving the following errors consistently:
Error: response.text: Protocol error (Network.getResponseBody): Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIStreamListener.onDataAvailable]

[Estansel]

I can also confirm that we are experiencing this issue. Both response.body() and response.text() produced errors others reported here. We are on 1.58.1 on latest Firefox

[dgozman]

Investigation notes:

• this fails while decompressing brotli, somewhere inside converter.onDataAvailable() call, most likely in nsHTTPCompressConv::OnDataAvailable.
• there was substantial brotli-related work around previous Firefox release: https://phabricator.services.mozilla.com/D258125,
• there has been a recent bugfix there as well: https://phabricator.services.mozilla.com/D274324.

Repro script:

import { test, expect } from '@playwright/test';
import fs from 'fs';

test('wait for response and log request body', async ({ page }) => {
  const promise = page.waitForResponse(
    (response) =>
      response.request().method() === 'GET' &&
      response.request().url().includes('cdos,hsm,jsa,mb4ZUb,cEt90b,SNUn3,qddgKe,sTsDMc,dtl0hd,eHDfl,YV5bee,d,csi') &&
      response.status() === 200
  );

  await page.goto('https://google.com');

  const response = await promise;
  console.log(response.request().url());
  console.log(await response.allHeaders());
  const responseBody = await response.body();
  await fs.promises.writeFile('response.txt', responseBody);
});

[spsaurabhpandey]

We're also experiencing this issue in our test suite after upgrading to Playwright v1.58.0. The error occurs when trying to read response bodies from GET requests in Firefox.

Error encountered:
Error: response.json: Protocol error (Network.getResponseBody): Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIStreamListener.onDataAvailable]

Workaround implemented:

We've implemented a workaround using page.route() with route.fetch() to capture response bodies before Firefox evicts them. The key is to intercept the request at the route level and capture the body immediately:
pescript
const routeHandler = async (route: Route) => {
const response = await route.fetch();
const body = await response.text();
capturedBodies[routeKey] = body;
await route.fulfill({
status: response.status(),
headers: response.headers(),
body: body,
});
};

await page.route(routeMatcher, routeHandler);

This approach ensures the response body is captured synchronously during the route interception, before Firefox can evict it from memory.

[niksauer]

We've implemented a workaround using page.route() with route.fetch() to capture response bodies before Firefox evicts them. The key is to intercept the request at the route level and capture the body immediately:

Works great, thank you!

[david-cako]

+1

Only throws on Firefox:

const responsePromise = this.page.waitForResponse(r => r.url().includes('...'));
const response = await responsePromise;
const obj = await response.json();