Welcome to the October edition of the Engineering Effectiveness Newsletter! The Engineering Effectiveness org makes it easy to develop, test and release Mozilla software at scale. See below for some highlights, then read on for more detailed info!
October 2021
Highlights
- Treeherder and Push Health now both have a link to Pernosco for reproducing try and autoland test failures (currently only for Linux 64 bit builds)
- Tab Unloading on Windows shipped in Firefox 93!
- Read the blog post on Hacks for more technical information
- The feature also landed for macOS on Nightly
- Brendan’s new method to handle soft masks and Calixte’s improvements to text selection fixed more than 20 long standing issues in our PDF viewer!
- Firefox Focus Nightly and Beta builds are now available on Google Play. Sign up to help the team test them!
Contributors
- Jane Kotovich (janekotovich)
- Catherine (catherinemds)
Detailed Project Updates
Bugzilla 
and Bugbug 
and Bugbug 
- Marco made the autonag bot politely ask users to set the “Regressed By” field, if they set the “Has Regression Range” field to “yes”
- Marco changed the autonag bot to nag about needinfos that go unanswered for a long time, on bugs that are marked as affecting a recent Firefox
- Ksenia improved GitHub support in bugbug, by making it possible to define repo-specific DBs (first next step to enable bugbug on mobile projects)
- dkl added more rate limiting and abuse protection to BMO
Build System and Mach Environment
- Team effort by Andi and Glandium to upgrade the build environment to clang-13
- Alex joined the build team
CI and Treeherder 
- Focus for Android now has taskgraph support for nightly, beta and releases in alignment with the rest of mobile.
- Treeherder and Push Health now both have a link to Pernosco for reproducing try and autoland test failures (currently only for Linux 64 builds).
Lint, Static Analysis and Code Coverage
- Calixte improved shutdown performance on Windows code coverage builds by making LLVM stop flushing memory-mapped files and let the OS handle it.
- Marco fixed a Rust coverage bimodality issue, due to sccache.
OS Integration and Security 
- Tab Unloading on Windows shipped in Firefox 93 along with a technical blog post announcing it. The feature landed for macOS on Nightly where it will stay while we test and experiment.
PDF.js 
- Read about the journey to implement AcroForm, JS, Tagged PDFs, XFA in this blog post on Hacks!
- Brendan fixed soft mask handling which closed 10+ PDF rendering bugs and improved the rendering speed of a number of PDFs.
- Calixte added support for the ResetForm action in AcroForms, supporting buttons in PDFs to reset forms
- Calixte changed the way pdf.js handles text selection, fixing a lot of white space and copy/paste bugs
- Jane Kotovich added support for the securityHandler property in the JS API and fixed a XFA bug preventing some images to be shown
- Catherine fixed a bug with some links in XFA
Phabricator 
, moz-phab, and Lando 
, moz-phab, and Lando 
- Zeid and Andi added a warning to Lando if blocking issues have been detected (Lando: https://bugzilla.mozilla.org/show_bug.cgi?id=1699137, code-review: https://bugzilla.mozilla.org/show_bug.cgi?id=1728284)
Release Engineering 
and Management
and Management 
- Heitor joined the releng team!
- Firefox will be shipping in the Microsoft Store with the launch of 94.
- Focus Android Nightly and Beta builds are ready for testing on Google Play! Sign up today.
Version Control 
- :sheehan, :dhouse and many others worked to upgrade the hgmo SSL certificate and pinned fingerprints. Good news is we no longer require client-side pinning of certificates, so future certificate swaps will be a seamless experience. Thanks to everyone who helped make this a seamless transition!
Thanks for reading and see you next month!