I have my own Julia package called foo which is stored in /private/tmp/foo and looks like:
foo
├── Project.toml
└── src
└── foo.jl
I'd like to use it in an experiment I'm going to run. As such I
- Create a new dir called
barfor my experiments - Create a new Julia env to use
Julia,],activate . - I now install
foowith(bar) pkg> dev /private/tmp/foo
I can now use foo within bar
julia> import foo
[ Info: Precompiling foo [79e59c38-1f99-4492-a045-e17729c6f495]
julia> foo.greet()
Hello World!
I now install Pluto with (bar) pkg> add Pluto, and open a new Pluto notebook. Even though I’m still in the bar env, which has foo installed I get a ArgumentError: Package foo not found in current path: as shown in the image below.
How can I create my own module, install and use it within a notebook? Ideally with Revise.jl still working.

Have you checked that you are still in it? Did you manually activate the environment?
In recent versions, Pluto notebooks have their own individual environments that are stored inside the notebook file. You can either:
devyour package inside this notebook environment too, or