1743185 - Use "hg" with Python 3 instead of Python 2

Status: RESOLVED FIXED

(Firefox Build System :: MozillaBuild, task, P3)

Description

[Mitchell Hentges [:mhentges] 🦀]

Mercurial 6.0 is the last release to support Python 2.

However, there's an outstanding bug with Mercurial and MSYS environments where the pager won't work (so, hg config ..., hg show ..., etc will just immediately exit without printing anything).

Comment 2

[Mitchell Hentges [:mhentges] 🦀]

Ooh, Alex's recent findings on a ./mach show-log issue have uncovered the PYTHONLEGACYWINDOWSSTDIO environment variable, which works around this very problem.

Comment 3

[Mitchell Hentges [:mhentges] 🦀]

Attachment: Bug 1743185: Use Mercurial with Python 3

The blocking "no output pager" bug is worked around by
using hg.exe instead of the text-based hg executable.

Work around this with an alias, and move Mercurial setup to Python 3.

Depends on D136414

Comment 4

[Mitchell Hentges [:mhentges] 🦀]

Attachment: Bug 1743185: Remove Python 2

Python 2 is no longer needed now that Mercurial is used with Python 3.

Depends on D136415

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/mozilla-build/rev/71bb2c60bade
Use Mercurial with Python 3 r=glandium
https://hg.mozilla.org/mozilla-build/rev/6365f1810e5a
Remove Python 2 r=glandium

Comment 6

[garrona]

Note on that: Python 3.9 does not support Windows 7.
You probably don't care enough to revert to 3.8 (which would be very nice), but at least mention it on the Wiki page.

Theoretically it should work with https://github.com/nalexandru/api-ms-win-core-path-HACK but at least for me, mach bootstrap freezes at the "Please choose the version of Firefox you want to build" step and then crashes with

OSError: [WinError 8] Not enough memory resources are available to process this command

File "M:\x\mozilla-source\mozilla-release\python\mozboot\mozboot\mach_commands.py", line 43, in bootstrap
  bootstrapper.bootstrap(command_context.settings)
File "m:\x\mozilla-source\mozilla-release\python\mozboot\mozboot\bootstrap.py", line 273, in bootstrap
  prompt_choice = self.instance.prompt_int(
File "m:\x\mozilla-source\mozilla-release\python\mozboot\mozboot\base.py", line 567, in prompt_int
  choice = input(prompt)

And memory should not really be an issue, I have 5 GB of available RAM and there is no spike in usage at all.

Comment 7

[garrona]

This seems to be some issue with the input() command. If I change mozilla-release\python\mozboot\mozboot\base.py to not have the input, but instead just return what I would have selected, it runs fine.