Running Mercurial with a custom Python version: version mismatch

[Thomas De Schampheleire]

Hi Matt,

On Fri, Aug 29, 2014 at 6:23 PM, Matt Mackall <mpm at selenic.com> wrote:
[..]
>
> On the other hand, it's trivial to install multiple versions of
> Mercurial linked against multiple versions of Python:
>
> $ hg clone hg hg3.1-python2.5
> $ cd hg3.1-python2.5
> $ hg co 3.1
> $ make PYTHON=python2.5 local
> $ ln -s $PWD/hg ~/bin/hg3.1-python2.5
>
> (I actually have over 100 releases of Mercurial in my path..)

Wouldn't it make sense that Mercurial remembers which Python path was
used in the installation and reuses the same path throughout its
future execution?

The method you suggest requires the users to be fully aware of the
python version in place and create a local Mercurial installation to
match it.

For a system administrator that wants to upgrade Mercurial from a
release where the check is not yet in place (for example Mercurial
2.6) to Mercurial 3.1, this is challenging as Mercurial will suddenly
fail to work for users that have a custom Python version.

Best regards,
Thomas