# Should I use \`\]add\` or \`\]develop\` to access local packages from my main environment?

**URL:** <https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115>\
**Category:** General Usage\
**Tags:** package\
**Created:** [April 27, 2022, 8:53am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115 "2022-04-27T08:53:09Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![maxkapur](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/maxkapur/32/21208_2.png) [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Post date:** [April 27, 2022, 8:53am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/1 "2022-04-27T08:53:09Z")

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Scenario: I have a package, say `Widgets`, which exists in a public Github repository (but not in the Julia package repo) at [github.com/maxkapur/Widgets](http://github.com/maxkapur/Widgets).

I have also `git clone`d Widgets to my home folder for development purposes.

Normally, if I want to play in the REPL with one of the functions in Widgets, I open a terminal in `~/Widgets` and run `julia --project`.

Now, however, I would like to use the Widgets package in my “main” Julia environment. That is, the one I get when I run `julia` from a terminal without the project flag. (What is the proper name for this environment?)

In other words, I want to add Widgets to my main Julia project.

From looking at the docs, it seems like there are six ways to do this: run `julia`, then enter at the REPL

- `add ~/Widgets`
- `add github.com/maxkapur/Widgets`
- `develop ~/Widgets`
- `develop github.com/maxkapur/Widgets`
- `develop --local ~/Widgets`
- `develop --local github.com/maxkapur/Widgets`

Which one should I use? I am interested in the following issues:

- If I update the package on Github, will my local environment automatically update?
- If I update the package on Github, will I be able to update my local environment using `]update`?
- If I update the package on Github and then pull changes to `~/Widgets`, will my local environment automatically update?
- If I update the package on Github and then pull changes to `~/Widgets`, will I be able to update my local environment using `]update`?

(I am typing this on my phone in a subway; please pardon any syntactical errors.)

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<div class="post-metadata">

**Author:** ![jishnub](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jishnub/32/33620_2.png) [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Post date:** [April 27, 2022, 9:26am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/2 "2022-04-27T09:26:37Z")

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You definitely want one of

> [@maxkapur](#):
>
> - `develop ~/Widgets`
> - `develop github.com/maxkapur/Widgets`
> - `develop --local ~/Widgets`
> - `develop --local github.com/maxkapur/Widgets`

The `--local` flag is only relevant if you’re using a GitHub link, as it determines where the clone will be saved (`--local` uses a relative path whereas `--shared` uses an absolute path). It’s irrelevant if you’re specifying a local path directly.

The difference between using a local path and a GitHub link is that in the latter case, a clone will be fetched and used, whereas in the former case your local copy will be used. In no case will an update on GitHub be automatically fetched, unless you specifically pull the changes, or update your project. In each case, what you’ll be using is ultimately the local copy of the project, and not what’s on GitHub.

> - If I update the package on Github, will my local environment automatically update?
> - If I update the package on Github, will I be able to update my local environment using ]update?  
> issues:
> - If I update the package on Github and then pull changes to ~/Widgets, will my local environment automatically update?
> - If I update the package on Github and then pull changes to ~/Widgets, will I be able to update my local environment using ]update?

The answer to the first is no. If you have added your package using `develop --local link`, the answer to the next three is yes. The pulled changes will be automatically used, and you don’t need to update your project every time.

Even if you’re directly editing your local clone that the project is pointing to without pushing to GitHub, the changes will be incorporated automatically.

If you have a local copy at `~/Widgets` which is synced with the copy on GitHub, and you add your package as `develop --local link`, you’ll end up with two copies of the project, and your project will use the local copy that is at `cwd()/dev`. This may be out of sync with the copy at `~/Widgets`, unless you keep fetching changes from GitHub. This is probably not what you want. You want to use

`develop ~/Widgets`

and edit your package as you want. The local changes to the package will be incorporated in your project. You may push your changes to GitHub, but this is not necessary for you to receive the updates, as they’re available locally.

You probably don’t want `add`, as this will track specific commits or tags in the project, and won’t incorporate uncommitted changes. In case this is what you want, you will need to explicitly use `]update` to change the commit that is being tracked.

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<div class="post-metadata">

**Author:** ![maxkapur](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/maxkapur/32/21208_2.png) [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Post date:** [April 27, 2022, 10:31am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/3 "2022-04-27T10:31:09Z")

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Thank you!

> [@jishnub](#):
>
> Even if you’re directly editing your local clone that the project is pointing to without pushing to GitHub, the changes will be incorporated automatically.

What happens, then, if I modify `~/Widgets/Project.toml` in a way that breaks my dependency tree? For example, suppose I am on v0.23 of a package Fidgets.jl in my main environment and I edit the deps in `~/Widgets/Project.toml` to require Fidgets.jl v0.24? Will Julia sort everything out if I do `]update`?

> [@jishnub](#):
>
> You want to use
> 
> `develop ~/Widgets`
> 
> and edit your package as you want.

After I do this, does calling `julia --project` from `~/Widgets` become superfluous?

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<div class="post-metadata">

**Author:** ![jishnub](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jishnub/32/33620_2.png) [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Post date:** [April 27, 2022, 10:35am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/4 "2022-04-27T10:35:07Z")

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> Will Julia sort everything out if I do `]update` ?

yes, it should, as I understand it.

> After I do this, does calling `julia --project` from `~/Widgets` become superfluous?

There are two projects here: one being your main Julia environment, and the other being your package `Widgets`. If you are planning to edit the contents of your package, you need to use `julia --project` from `~/Widgets` to access its dependencies. On the other hand, if you just want to use `Widgets` in your main environment, you don’t need to activate it; in fact, you shouldn’t, as it might lead to issues in resolving dependencies. In the second case, you should simply run `julia` followed by `using Widgets`, once you have run `develop ~/Widgets` in your main environment.

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<div class="post-metadata">

**Author:** ![maxkapur](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/maxkapur/32/21208_2.png) [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Post date:** [April 27, 2022, 10:41am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/5 "2022-04-27T10:41:59Z")

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Follow-up question: suppose I decide to do something silly and develop my own local package called Plots.jl (even though a package of the same name already exists in the repos). Is there a way I can `]develop` my project under an alias, say `]develop ~/Plots as SillyPlots`, that won’t break other packages in my environment that have the real Plots.jl as a dependency?

Or what about this: Suppose I haven’t installed Plots.jl yet, nor any package that names Plots.jl as a dependency. I create my own Plots.jl package locally that does something completely unrelated to plotting and `]develop ~/Plots`. Now what happens if I `]add StatsPlots`, which depends on the real Plots.jl? Will it try calling plotting functions from my local project and error, or will it install the real Plots.jl as an alias?

For that matter, what happens if I try to `]add Plots` in this scenario?

I am tempted to try these things myself but I don’t want to break my environment…

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<div class="post-metadata">

**Author:** ![maxkapur](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/maxkapur/32/21208_2.png) [@maxkapur](https://discourse.julialang.org/u/maxkapur)\
**Post date:** [April 27, 2022, 10:46am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/6 "2022-04-27T10:46:35Z")

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Aha. So suppose I have Fidgets.jl v0.24 installed on my main environment, and `Widgets.jl` names Fidgets.jl v0.23 as a dependency. If I now call `]develop ~/Widgets`, then my main environment will downgrade me to Fidgets.jl v0.23, right?

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<div class="post-metadata">

**Author:** ![jishnub](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/jishnub/32/33620_2.png) [@jishnub](https://discourse.julialang.org/u/jishnub)\
**Post date:** [April 27, 2022, 10:54am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/7 "2022-04-27T10:54:29Z")

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If you have strict compat settings in `Widgets` that pins `Fidgets` to `v0.23`, and this downgrade is possible in the main environment (i.e. no other package in the main environment depends on Fidgets `v0.24` specifically), then yes, it should downgrade `Fidgets` to `v0.23`.

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**Author:** ![Fliks](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fliks/32/2494_2.png) [@Fliks](https://discourse.julialang.org/u/Fliks)\
**Post date:** [April 27, 2022, 11:04am UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/8 "2022-04-27T11:04:11Z")

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> [@maxkapur](#):
>
> I am tempted to try these things myself but I don’t want to break my environment…

For playing around with packages and to test these things you can open a temporary environment with

```julia
] activate --temp

```

Since packages are disambiguated via an UUID you can have different packages with the same name as indirect dependencies, see [10. Project.toml and Manifest.toml · Pkg.jl](https://pkgdocs.julialang.org/v1/toml-files/#Multiple-package-with-the-same-name)

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**Author:** ![GunnarFarneback](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/gunnarfarneback/32/1827_2.png) [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)\
**Post date:** [April 27, 2022, 12:09pm UTC](https://discourse.julialang.org/t/should-i-use-add-or-develop-to-access-local-packages-from-my-main-environment/80115/9 "2022-04-27T12:09:56Z")

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> [@maxkapur](#):
>
> I am tempted to try these things myself but I don’t want to break my environment…

That’s an easily solved problem. Create an empty directory and point the environment variable `JULIA_DEPOT_PATH` there. Now you have a pristine Julia installation and can play around all you want without affecting anything you have in your `.julia`.