Ability to pin lein to a specific version

[raags]

I see that the script exports LEIN_VERSION right at the top; can we source a file say ~/$LEIN_HOME/lein-version and use that instead? Use case would be to pin lein to a specific version, and upgrade when needed/tested.

[hypirion]

I don't think that's necessary – first and foremost, we have lein upgrade vsn and lein downgrade vsn, so if you wanted to change to version 2.4.0 for example, you could just do lein downgrade 2.4.0.

The scripts are also standalone, so I tend to just copy the lein file when a new release comes out; You can e.g. copy the lein script to lein-2.4.0 and then do lein-2.4.0 downgrade 2.4.0 if you want it to refer to 2.4.0.

[technomancy]

If you want all users to be on the same version of Leiningen, I recommend copying bin/lein into the project repo itself and using that.

I would accept a patch to warn or abort on a mismatch, but it won't do any good for versions that already exist.