Announcing MozillaBuild 4.0 Release

[Mitchell Hentges]

MozillaBuild 4.0 is the "Snow Leopard" of MozillaBuild releases - almost no new features, but significant stability, usability and security improvements!

(Perhaps it's bad taste to use a macOS metaphor for Windows-specific software 😉)

Upgrade instructions are here, the full changelog is here, and you can download MozillaBuild 4.0 from here.

Upgrade notes

• Developers running Mach outside of MozillaBuild should still install this update, as the Firefox build uses tools from your local MozillaBuild installation.
  
• As always, do a `./mach clobber` after changing your MozillaBuild version.
• The new version of Mercurial has compatibility issues with `evolve` ("unhashable type: 'set'"), which can be fixed by running `./mach vcs-setup`.

Highlights

• Ported to MSYS2, significantly updating most tools/libraries.
• Some tools are now a whole decade more modern! 🎉
• This includes the `cygpath` utility for converting between Windows and Unix-y paths. See additional instructions on the MozillaBuild wiki.
  
• Windows Terminal is supported out-of-the-box.
• Use Windows' OpenSSH by default.
• Mercurial has been updated from 5.9.3 to 6.1.
• Python 3 upgraded to 3.9.10, Python 2 removed.
  
• `hg` now uses interactive "curses" mode by default.

Fixed

• `python3 -m venv` no longer fails with "WinError 2".
• Running `./mach try fuzzy` no longer makes it impossible to select or copy text.

Breaking changes

• Mercurial now uses "utf-8" by default.
• Due to the MSYS -> MSYS2 migration, a lot of underlying tools and libraries have changed.
• Automatically-bootstrapped tools have been removed (NSIS, mozmake, yasm).
• Python's `virtualenv` package is no longer installed by default. (use `python3 -m venv` instead).
• Python 2 is no longer available, and `python` now refers to Python 3.

Breaking user changes

• `nano` is now the default editor instead of `emacs`. Set "ui.editor" to "emacs" in ~/mercurial.ini or `export EDITOR="emacs.exe"` in your `.bash_profile` to use emacs again.
• Note that we've configured `hg`'s `nano` integration to automatically wrap lines at 80 characters to improve commit-message ergonomics.
• `hg` merge conflicts are now solved in text form by default. To use kdiff3 again, set `ui.diff` to `"kdiff3"` in ~/mercurial.ini.

💪😎👉 Happy Windows hacking in a far more ergonomic and modern environment 💪😎👉

--

Mitchell Hentges

Engineering Workflow

Mozilla

[Mitchell Hentges]

I also had to remove my ~/.mozbuild, it was full of old hg extensions that confused the new hg, and ./mach bootstrap refused to overwrite them. Maybe the wiki should mention that?

This is a compatibility issue that's specific to MozillaBuild 4.0, and most version-specific information is in the release notes (it could be hard to discover as an unconventional MB 4.0-specific section in the wiki).

Accordingly, in the "Upgrade Notes" of the announcement email, the third bullet point describes this hg extension issue and how to work around it ("./mach vcs-setup").

I wish that this could've been caught in a more automated fashion, but unfortunately it could only be solved by documenting it - which makes it possible to miss.

c:\mozilla-build\python3\Scripts\hg started with "#!c:\mozillabuild-stage\mozilla-build\python3\python.exe", which made my hg-using scripts fail. Fixed by removing the spurious "mozillabuild-stage\".

Thanks for noting this, I've documented the workaround over here.

On Wed, Mar 23, 2022 at 10:43 PM Gerald Squelart <sque...@gmail.com> wrote:

Thank you for the update.

A couple of pain points for me:

- I also had to remove my ~/.mozbuild, it was full of old hg extensions that confused the new hg, and ./mach bootstrap refused to overwrite them. Maybe the wiki should mention that?

- c:\mozilla-build\python3\Scripts\hg started with "#!c:\mozillabuild-stage\mozilla-build\python3\python.exe", which made my hg-using scripts fail. Fixed by removing the spurious "mozillabuild-stage\".

Cheers,

Gerald