direnv.md

direnv

direnv and mise both manage environment variables based on directory. Because they both analyze the current environment variables before and after their respective "hook" commands are run, they can sometimes conflict with each other.

If you have an issue, it's likely to do with the ordering of PATH. This means it would really only be a problem if you were trying to manage the same tool with direnv and mise. For example, you may use layout python in an .envrc but also be maintaining a .tool-versions file with python in it as well.

A more typical usage of direnv would be to set some arbitrary environment variables, or add unrelated binaries to PATH. In these cases, mise will not interfere with direnv.

mise inside of direnv (use mise in .envrc)

::: warning Update 2024-01-21: after use mise has been out for a while, the general impression I have is that while it technically functions fine, not many people use it because the DX is notably worse than either switching to mise entirely or using mise activate alongside direnv.

The project direction of mise has changed since this was written and the new direction is for it to be capable of replacing direnv completely for any use-case. This likely won't end up as a drop-in replacement for direnv like with asdf, but solving the same problems in different ways. See environments for more details.

I have had virtually no reports of problems with use mise in the year it has been out. This could be because virtually is using it, or it has been surprisingly stable. I genuinely don't know which. If you try it or use it regularly let me know.

While I have no immediate plans or reasons to do this now, I could see this functionality being the target of a future deprecation. Not because it's a maintenance burden, but because it just hasn't seemed like a particularly useful solution and it may help focus mise on the functionality that does work for users. :::

If you do encounter issues with mise activate, or just want to use direnv in an alternate way, this is a simpler setup that's less likely to cause issues—at the cost of functionality.

This may be required if you want to use direnv's layout python with mise. Otherwise there are situations where mise will override direnv's PATH. use mise ensures that direnv always has control.

To do this, first use mise to build a use_mise function that you can use in .envrc files:

mise direnv activate > ~/.config/direnv/lib/use_mise.sh

Now in your .envrc file add the following:

use mise

direnv will now call mise to export its environment variables. You'll need to make sure to add use_mise to all projects that use mise (or use direnv's source_up to load it from a subdirectory). You can also add use mise to ~/.config/direnv/direnvrc.

Note that in this method direnv typically won't know to refresh .tool-versions files unless they're at the same level as a .envrc file. You'll likely always want to have a .envrc file next to your .tool-versions for this reason. To make this a little easier to manage, I encourage not actually using .tool-versions at all, and instead setting environment variables entirely in .envrc:

export MISE_NODE_VERSION=20.0.0
export MISE_PYTHON_VERSION=3.11

Of course if you use mise activate, then these steps won't have been necessary and you can use mise as if direnv was not used.

If you continue to struggle, you can also try using the shims method.

Do you need direnv?

While making mise compatible with direnv is, and will always be a major goal of this project, I also want mise to be capable of replacing direnv if needed. This is why mise includes support for managing env vars and virtualenv for python using .mise.toml.