For my public libs I have created demo apps. During development the demo app should depend on the development version of the library; so I use path: ../my_lib. However, when the demo app is cloned by a user it should depend on the Hex version instead. Currently I set an environment flag which toggl…

I do this in the demo for one of my projects, in “mix.exs”: defp deps do [ {:phoenix, "~> 1.7.14"}, ..., my_lib_dep() ] end defp my_lib_dep() do if File.exists?(Path.join(__DIR__, "../my_lib/mix.exs")) do {:my_lib, path: "../my_lib"} else {:my_lib, "~> 0.1.0"} …

I didn’t do it this way because it feels wrong to reach out into an unsuspecting user’s filesystem to execute code (at least from an unsanctioned directory). While I’m fully aware it’s super edge case, you never know what people have on their machines. For example, maybe they clone the example app…

If you don’t like that option, you can always use a environment variable to achieve the same, the important point is as @Nicodemus mentioned: you can execute elixir code inside of mix.exs, which is a very powerful concept.

@BartOtten already mentioned the env variable approach which I do like better. I’m certainly aware mix.exs is just code which I thought was implied by my saying I already considered @Nicodemus ’s approach (well, same goes for checking an env var, really).

Indeed, after reading it again I misunderstood the question. Addressing your previous concerns, just opening a project with a LSP carries risk of executing stuff you are unaware of, especially since elixir metaprogramming allows execution of code at compile-time.

Current implementation is like this. I did commit an .envrc file which sets the path. It seems checking path existence is the only ‘fully native’ solution. Combining it with env override and a warning might hit the sweet spot. defp routex_dep() do if path = System.get_env("ROUTEX_PATH") do …

If the solution works without many hitches, what is inherently wrong with it? I guess you could use a mix task to ask the user the default option before he starts the project, but I don’t see that as a much better approach.

Not much. But as I can imagine others having the same use case, I wondered if there would be a better way. And because I rather have a minimum of helper apps (such as direnv).

Ya, same here. There are easy ways to make it work but none that I can think of feel “right.” Though I do quite like the “Doggo way.” It does also mean shipping the demo with package but it’s not like it gets compiled into peoples’ apps or anything. And of course if you want multiple demos then …

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How to switch between local or Hex dependency?

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BartOtten October 31, 2024, 9:05pm 11

—nvm—..