How to build old versions?

I’ve got a user that needs an older version of a package I’m maintining that’s been recently added to conda-forge. How can I do that?

I think I can put the recipe in a new branch, and then it will get built. – is that correct? Or should I “downdate” the recipe in main to teh old version, get it built, and then update it again? that seems a bit awkward…


  • Chris
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The usual process is to create a new branch for the old version yes. There a few tricks to make it less painful.

Let’s say you have a package called phone with version 3.4 but you want 2.7. Version 3.4 is currently being built from main. I’d do the following things:

  1. Sync our clone with feedstock: git checkout main && git pull upstream/main
  2. New branch: git checkout -b 2.x
  3. Prevent an accidental upload on the branch push. We don’t want our freshly pushed branch to create a new upload. We can avoid this with two methods:
    1. Make the recipe fail on purpose. This might be an exit 1 very early in the build script, or a bad URL for the source (e.g. add gibberish to the domain name), or a unsatisfiable dependency.
    2. Add upload_on_branch: main to conda-forge.yml and rerender locally with conda-smithy rerender.
  4. Push the 2.x branch to upstream (i.e. conda-forge/*-feedstock, not your fork)
  5. Create a new branch off 2.x: git checkout -b build-old-2.7. Add the necessary changes for your old version, undoing whatever you did on (3) (i.e. revert the intentional errors or make sure upload_on_branch: 2.x + rerender).
  6. Push build-old-2.7 to origin. This time it is the fork, not upstream!
  7. Open a PR targeting 2.x and proceed as usual with your code reviews.

I hope that’s useful!

PS: Steps 1-5 would be nice to have as a subcommand, I guess. Imagine @conda-forge-admin, please create branch 2.x.

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PS: Steps 1-5 would be nice to have as a subcommand, I guess. Imagine @conda-forge-admin, please create branch 2.x .

Ooh, nice idea! :+1:

thanks – that does seem a bit more involed than i’d like – I do likethe command idea.

But meanwhile, I’ll do it by hand.