fast-export fails if python3 is sytem-wide default

[houseofsuns]

If the system default python is python3 (i.e. the symlink is /usr/bin/python -> /usr/bin/python3) then fast-export fails as it is python2 only. The error is in this case rather confusingly

veelai@zaphod ~/fast-export $ python3 hg-fast-export.py 
Traceback (most recent call last):
  File "fast-export/hg-fast-export.py", line 6, in 
    from mercurial import node
ImportError: No module named mercurial

A possible solution is to replace PYTHON=${PYTHON:-python} by PYTHON=${PYTHON:-python2} in the shell scripts and '#!/usr/bin/env python' by '#!/usr/bin/env python2' in the python scripts. This should work in most environments, with one caveat: Debian as greatest distribution under the sky decided to be extravagant and does not ship a python2 symlink, but only python2.6 and similar.

[frej]

Is this still a problem?

[bigbn]

Still. Python3 can't use package mercurial, because it is not ported from python 2.
http://stackoverflow.com/questions/16904468/cant-install-mercurial-package-with-pip-under-python-3-2

[frej]

Ok. I'll leave it open then...

[mathben]

It's supported now!

> pip3 show mercurial
Name: mercurial
Version: 4.2.2
Summary: Fast scalable distributed SCM (revision control, version control) system
Home-page: https://mercurial-scm.org/
Author: Matt Mackall and many others
Author-email: mercurial@mercurial-scm.org
License: GNU GPLv2 or any later version
Location: /usr/lib/python3.6/site-packages
Requires:

But I got this error in execution :

> ../fast-export/hg-fast-export.sh -r ../eigen
Traceback (most recent call last):
File "~/fast-export/hg2git.py", line 31, in setup_repo
myui=ui.ui(interactive=False)
TypeError: init() got an unexpected keyword argument 'interactive'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/fast-export/hg-fast-export.py", line 505, in
notes=options.notes,encoding=encoding,fn_encoding=fn_encoding))
File "/fast-export/hg-fast-export.py", line 381, in hg2git
ui,repo=setup_repo(repourl)
File "~/fast-export/hg2git.py", line 34, in setup_repo
myui.setconfig('ui', 'interactive', 'off')
File "/usr/lib/python3.6/site-packages/mercurial/ui.py", line 388, in setconfig
cfg.set(section, name, value, source)
File "/usr/lib/python3.6/site-packages/mercurial/config.py", line 75, in set
'config values may not be unicode strings on Python 3')
AssertionError: b'config values may not be unicode strings on Python 3'

[nobody93]

Hi,

I thought I wrote following comments yesterday, but could not see it. Sorry I have to write it again, I've clone it from the master branch but I still have following errors, it runs python 2. Anyway, is it fixed in any branch? Or should I install python extra modules manually?

File "/storage/data/SolarAnalytics/HAN/fast-export/hg-fast-export.py", line 7, in
from mercurial.scmutil import revsymbol
ImportError: cannot import name revsymbol

[frej]

@nobody93: Looks like a duplicate of #132.

[jeandersonbc]

@houseofsuns if you change PYTHON=${PYTHON:-python} to PYTHON=${PYTHON:-python2} at this location, will it work?

[jeandersonbc]

@houseofsuns My bad, I didn't notice you mentioned this solution. I tried it here and it works too. If the scripts have a dependency on Python2, perhaps it should be clearly specified on the scripts but I do agree this project should consider moving to Python3.

[frej]

@jeandersonbc: As long as Mercurial does not fully support Python >= 3 porting fast-export to Python 3 is pretty pointless.

Commit ac60034 should make it clear that Python 3 is not supported even if the requirements section in the readme is ignored. With PEP 394 now providing guidance on what a Python script should assume, I believe this bug is finally fixed.