1388452 - Require Python 3 to build Firefox

Status: RESOLVED DUPLICATE of bug 636155

(Firefox Build System :: General, enhancement)

Description

[Gregory Szorc [:gps]]

Python 2 will not be maintained starting sometime in 2020. Python 3 is the future.

At some point, we'll want to require Python 3 to build Firefox. This bug tracks that requirement.

I'm not sure exactly when we'll cross this bridge. We could probably do it soon, as MozillaBuild is now shipping Python 3.6 and I think most *NIX distros have Python easily available as a package. But until we have a compelling reason to require Python 3 to build, I'm not inclined to do it. If nothing else, our adoption of Rust is causing some grief for downstream packagers and I'd prefer to give them a reprieve before we hit them with Python 3.

As for what version of Python 3 to require when we establish the requirement, we should try to require the latest version as possible, as working around bugs and missing features from older versions is a time sink and slows us down. The main impediment to requiring the latest version is difficulties installing that version on various operating system and downstream packaging requirements.

If we made the transition today, I'd strongly prefer to require at least 3.5. The reason is that it is considerably more difficult to write Python that runs on both 2.7 and 3 for versions <3.5. This is due to the lack of the % operator on bytes types, which was restored in 3.5.

If I had to venture a guess, I'd say we'll likely require Python 3 to build sometime in the first half of 2018. But if we find a compelling reason to require it sooner, it could happen in 2017.

Comment 1

[Landry Breuil (:gaston)]

(In reply to Gregory Szorc [:gps] from comment #0)

> If nothing else, our adoption of Rust is causing some grief for downstream
> packagers and I'd prefer to give them a reprieve before we hit them with
> Python 3.

You don't say :)

Just kidding, as far as OpenBSD is concerned we'd have no issue switching to 3.6.

Comment 2

[Gary Kwong [:gkw] [:nth10sd] (NOT official MoCo now)]

Possible dupe of bug 636155?

Comment 3

[Gregory Szorc [:gps]]

Of course there's a 7 year old bug for this...