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Andrey Lushnikov 18e690e234
browser(firefox): fix firefox crashes (#9563)
2 days ago
chromium browser(chromium): roll to r931772 (#9532) 2 days ago
ffmpeg devops: build FFMPEG using MacOS 11 (#9402) 1 week ago
firefox browser(firefox): fix firefox crashes (#9563) 2 days ago
firefox-beta browser(firefox): fix firefox crashes (#9563) 2 days ago
webkit browser(webkit): fix build on ubuntu 18.04 and mac (#9540) 2 days ago
winldd Revert "browser(winldd): attempt to fix dependency loading on windows (#7790)" (#7948) 3 months ago devops: add FF debug build instructions (#9534) 2 days ago devops: fix `//browser_patches/{,}` scripts (#9515) 3 days ago devops: fix expected ffmpeg os host 1 week ago devops: fix `//browser_patches/{,}` scripts (#9515) 3 days ago devops: move Firefox and WebKit checkouts to $HOME (#9485) 3 days ago devops: move Firefox and WebKit checkouts to $HOME (#9485) 3 days ago
repack-juggler.mjs devops: fix juggler repacking (#9556) 2 days ago
sanitize_and_compress_log.js devops: use node.js to gzip logs 2 years ago chore: quote all bash variables when used (#8066) 2 months ago chore: quote all bash variables when used (#8066) 2 months ago devops: enforce hard xcode version match for browser builds (#7591) 3 months ago

Contributing Browser Patches

Firefox and WebKit have additional patches atop to expose necessary capabilities.

Ideally, all these changes should be upstreamed. For the time being, it is possible to setup a browser checkout and develop from there.

WebKit upstream status

1. Setting up local browser checkout

From the playwright repo, run the following command:

$ ./browser_patches/ firefox <path to checkout>

(you can optionally pass "webkit" for a webkit checkout)

If you don't have a checkout, don't pass a path and one will be created for you in ./browser_patches/firefox/checkout

NOTE: this command downloads GBs of data.

This command will:

  • create a browser_upstream remote in the checkout
  • create a playwright-build branch and apply all playwright-required patches to it.

2. Developing a new change

You want to create a new branch off the playwright-build branch.

Assuming that you're under ./browser_patches/firefox/checkout:

$ git checkout -b my-new-feature playwright-build
$ # develop my feature on the my-new-feature branch ....

3. Exporting your change to playwright repo

Once you're happy with the work you did in the browser-land, you want to export it to the playwright repo.

Assuming that you're in the root of the playwright repo and that your browser checkout has your feature branch checked out:

$ ./browser_patches/ firefox <path to checkout>

This script will:

  • create a new patch and put it to the ./browser_patches/firefox/patches/
  • update the ./browser_patches/firefox/ if necessary
  • bump the ./browser_patches/firefox/BUILD_NUMBER number.

If you omit the path to your checkout, the script will assume one is located at ./browser_patches/firefox/checkout

Send a PR to the Playwright repo to be reviewed.

4. Rolling Playwright to the new browser build

Once the patch has been committed, the build bots will kick in, compile and upload a new browser version to all the platforms. Then you can roll the browser:

$ node utils/roll_browser.js chromium 123456


See browser stdout/stderr

Set the DEBUG=pw:browser environment variable to see it.


Debug build

When compiling set the FF_DEBUG_BUILD=1 environment variable.

Stack trace

In //mozglue/misc/StackWalk.cpp add


In native code use

#include "mozilla/StackWalk.h"
// ...

If the stack trace is still mangled cat it to tools/rb/


Upstream documentation:


Module name is a string passed to the mozilla::LazyLogModule of the corresponding component, e.g.:

LazyLogModule gHttpLog("nsHttp");

Inside Juggler, you can use dump('foo\n').



Inside Objective-C you can use NSLog.

NSLog(@"Foobar value: %@", value);

Debugging windows

In Source\WTF\wtf\win\DbgHelperWin.cpp replace

#if !defined(NDEBUG) with #if 1

Then regular WTFReportBacktrace() works.

Enable core dumps on Linux

mkdir -p /tmp/coredumps
sudo bash -c 'echo "/tmp/coredumps/core-pid_%p.dump" > /proc/sys/kernel/core_pattern'
ulimit -c unlimited

Then to read stack traces run the following command:

# To find out crashing process name
file core-pid_29652.dump
# Point gdb to the local binary of the crashed process and the core file
gdb $HOME/.cache/ms-playwright/webkit-1292/minibrowser-gtk/WebKitWebProcess core-pid_29652
# Inside gdb update .so library search path to the local one
set solib-search-path /home/yurys/.cache/ms-playwright/webkit-1292/minibrowser-gtk
# Finally print backtrace