[BUG] Unable to upload big file on firefox.

Context:

• Playwright Version: 1.6.2
• Operating System: Win 10
• Node.js version: 14
• Browser: Firefox

Code Snippet

const {firefox} = require('playwright');
const path = require('path');

(async function() {
    const browser = await firefox.launch({headless: false});
    try {
        const page = await browser.newPage();
        await page.goto('https://pdf.io/compress/');
        await page.setInputFiles('#upload_button input', path.join(process.cwd(), 'big.pdf'));
    } finally {
        await browser.close();
    }
})();

Describe the bug

When I try to upload big pdf, for example this one: http://research.nhm.org/pdfs/29985/29985-001.pdf I get an error in example unable to upload file. At the same time chrome uploads file well, also small files are uploaded well on firefox but big ones don’t.

[aslushnikov]

This is fixed now; the fix will be available in the next release - Playwright v1.12

Or on May 14 PST time in the @next channel: npm i playwright@next

[aslushnikov]

@achingbrain thank you for the awesome repro.

This happens due to the way our network instrumentation interacts with POST data in Juggler. Specifically, it looks like NetUtil.readInputStream call is both: a) racy & partial b) closing the stream, making the final rewind-back fail.

Note that this all only happens with Blob uploads as POST requests.