# Using a locally developed package

**URL:** <https://discourse.julialang.org/t/using-a-locally-developed-package/98320>\
**Category:** New to Julia\
**Tags:** package\
**Created:** [May 4, 2023, 1:43pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320 "2023-05-04T13:43:21Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![mmv](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mmv/32/26323_2.png) [@mmv](https://discourse.julialang.org/u/mmv)\
**Post date:** [May 4, 2023, 1:43pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/1 "2023-05-04T13:43:21Z")

</div>

Hi!

I developed a first package [`JMtk15`](https://github.com/mmverstraete/JMtk15) and now would like to use those functions in a second package `JMTools`. That first package appears to be loading correctly because

- the command `using JMtk15` does not generate any error messages,
- the JMtk15 package appears in the `Project.toml` of `JMTools` as expected, and
- a `const` definition in `JMtk15` is correctly retrieved:

```julia
julia> using JMTools

julia> using JMtk15

julia> JMtk15_src
"/Users/michel/Projects/MISR/MISR_Toolkit.1.5/JMtk15/src/"

```

However, when I call one of the `JMtk15` functions, I get error messages:

```julia
julia> misr_path = 168
168

julia> misr_orbit = 68050
68050

julia> bool = is_from_misr_path(misr_path, misr_orbit)
ERROR: UndefVarError: jMtkOrbitToPath not defined
Stacktrace:
 [1] is_from_misr_path(misr_path::Int64, misr_orbit::Int64)
   @ JMTools ~/Projects/MISR/MISR_Tools/JMTools/src/is_from_misr_path.jl:57
 [2] top-level scope
   @ REPL[6]:1

julia> bool = is_from_misr_path(misr_path, misr_orbit)
ERROR: UndefVarError: JMtk15 not defined
Stacktrace:
 [1] is_from_misr_path(misr_path::Int64, misr_orbit::Int64)
   @ JMTools ~/Projects/MISR/MISR_Tools/JMTools/src/is_from_misr_path.jl:57
 [2] top-level scope
   @ REPL[6]:1

```

where the first error message was generated by the code line 57

```julia
true_path = jMtkOrbitToPath(misr_orbit)

```

while the second error message was generated by the code line 57

```julia
true_path = JMtk15.jMtkOrbitToPath(misr_orbit)

```

That function is explicitly exported in `JMtk15.jl`.

So it looks like I am either missing a step or an instruction to make the functions of the local package `JMtk15` actually usable in the new local project `JMTools`.

However, I also found out (1) that although the source of `JMtk15` is located in a regular directory `/Users/michel/Projects/MISR/MISR_Toolkit.1.5/JMtk15`, Julia appears to load packages from a different location:

```julia
julia> pkgdir(JMtk15)
"/Users/michel/.julia/packages/JMtk15/hCUhn"

```

and (2) that the directory `.julia/packages/JMTk15` contains two oddly named subdirectories, each containing what looks like copies of the source code of `JMtk15`:

```plaintext
MicMac3 ~/.julia/packages/JMTk15 % ls -al
total 0
drwxr-xr-x@ 4 michel staff 128 May 2 10:27 .
drwxr-xr-x 36 michel staff 1152 Apr 28 16:59 ..
drwx------@ 11 michel staff 352 Apr 28 16:59 9eq0g
drwx------@ 11 michel staff 352 May 2 10:27 hCUhn

```

What is the role of those copies in `.julia/packages/JMTk15`? When do they get created and what is their purpose? Do I need to keep multiple copies (here 3: the working directory and two copies in `.julia/packages/`) of the package source files?

Any help will be greatly appreciated.

---

<div class="post-metadata">

**Author:** ![barucden](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/barucden/32/26154_2.png) [@barucden](https://discourse.julialang.org/u/barucden)\
**Post date:** [May 4, 2023, 2:04pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/2 "2023-05-04T14:04:43Z")

</div>

`~/.julia/packages/` is a directory where `Pkg` stores installed packages: The directories inside `.julia/packages/JMTk15` correspond to different versions of your package. They get created when you `Pkg.add` your package. They should not be identical copies.

To your original issue – could you share your `Manifest.toml` of `JMTools`?

Also, in search for where `JMtk15_src` comes from, I checked the source of `JMtk15` on github. Note that it should be possible to replace all the lines

```julia
include(JMtk15_src * "include/MisrCache_h.jl")

```

simply with

```julia
include("include/MisrCache_h.jl")

```

Then you don’t need `JMtk15_root`, `JMtk15_src`, …

---

<div class="post-metadata">

**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:** [May 4, 2023, 2:07pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/3 "2023-05-04T14:07:05Z")

</div>

This thread has some related discussion which might be helpful: [Add vs dev at a local path](https://discourse.julialang.org/t/add-vs-dev-at-a-local-path/58150)

---

<div class="post-metadata">

**Author:** ![mmv](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mmv/32/26323_2.png) [@mmv](https://discourse.julialang.org/u/mmv)\
**Post date:** [May 4, 2023, 2:33pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/4 "2023-05-04T14:33:51Z")

</div>

Hi @barucden,

Thanks for your quick response. I looked at the `Manifest.toml`, and indeed, it contains these lines:

```plaintext
MicMac3 ~/Projects/MISR/MISR_Tools/JMTools % cat Manifest.toml
# This file is machine-generated - editing it directly is not advised

julia_version = "1.8.5"
manifest_format = "2.0"
project_hash = "f480c51fbf8898cfbe1ab1453f805e0d22be89b7"

...

[[deps.JMtk15]]
deps = ["CEnum", "StaticArrays", "StringViews", "Test"]
path = "/Users/michel/.julia/packages/JMtk15/hCUhn"
uuid = "6c71635d-e68b-418f-880a-c8128ca9dc0a"
version = "0.1.0"

...

[[deps.libblastrampoline_jll]]
deps = ["Artifacts", "Libdl", "OpenBLAS_jll"]
uuid = "8e850b90-86db-534c-a0d3-1478176c7d93"
version = "5.1.1+0"
MicMac3 ~/Projects/MISR/MISR_Tools/JMTools % 

```

So I see that the dependency is specifically referring to the `.julia/packages/JMtk15/hCUhn` subdirectory…

Hi @GunnarFarneback,

Thanks also for your input. I’ve now

```plaintext
julia> pwd()
"/Users/michel/Projects/MISR/MISR_Tools/JMTools"

(JMTools) pkg> dev "/Users/michel/Projects/MISR/MISR_Toolkit.1.5/JMtk15"
   Resolving package versions...
    Updating `~/Projects/MISR/MISR_Tools/JMTools/Project.toml`
  [6c71635d] ~ JMtk15 v0.1.0 `~/.julia/packages/JMtk15/hCUhn` ⇒ v0.1.0 `~/Projects/MISR/MISR_Toolkit.1.5/JMtk15`
    Updating `~/Projects/MISR/MISR_Tools/JMTools/Manifest.toml`
  [6c71635d] ~ JMtk15 v0.1.0 `~/.julia/packages/JMtk15/hCUhn` ⇒ v0.1.0 `~/Projects/MISR/MISR_Toolkit.1.5/JMtk15`

```

That, in turn, has updated the `Manifest.toml` file which now reads:

```julia
[[deps.JMtk15]]
deps = ["CEnum", "StaticArrays", "StringViews", "Test"]
path = "/Users/michel/Projects/MISR/MISR_Toolkit.1.5/JMtk15"
uuid = "6c71635d-e68b-418f-880a-c8128ca9dc0a"
version = "0.1.0"

```

However, I still get the same error message:

```julia
julia> bool = is_from_misr_path(misr_path, misr_orbit)
ERROR: UndefVarError: JMtk15 not defined
Stacktrace:
 [1] is_from_misr_path(misr_path::Int64, misr_orbit::Int64)
   @ JMTools ~/Projects/MISR/MISR_Tools/JMTools/src/is_from_misr_path.jl:57
 [2] top-level scope
   @ REPL[10]:1

```

Is there anything else that needs to be setup?

---

<div class="post-metadata">

**Author:** ![barucden](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/barucden/32/26154_2.png) [@barucden](https://discourse.julialang.org/u/barucden)\
**Post date:** [May 4, 2023, 2:42pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/5 "2023-05-04T14:42:24Z")

</div>

Just to make sure – are you really `using JMtk15` _inside_ `JMTools` and not just the Julia REPL session?

---

<div class="post-metadata">

**Author:** ![mmv](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mmv/32/26323_2.png) [@mmv](https://discourse.julialang.org/u/mmv)\
**Post date:** [May 4, 2023, 2:52pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/6 "2023-05-04T14:52:15Z")

</div>

@barucden,

Excellent point: I have now added `using JMtk15` inside the `JMTools.jl` file, and lo and behold:

```julia
julia> bool = is_from_misr_path(misr_path, misr_orbit)
true

```

Thanks to both of you for resolving this issue so quickly.

---

<div class="post-metadata">

**Author:** ![HanD](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/hand/32/213908_2.png) [@HanD](https://discourse.julialang.org/u/HanD)\
**Post date:** [May 5, 2023, 6:57am UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/7 "2023-05-05T06:57:20Z")

</div>

> [@mmv](#):
>
> What is the role of those copies in `.julia/packages/JMTk15`? When do they get created and what is their purpose? Do I need to keep multiple copies (here 3: the working directory and two copies in `.julia/packages/`) of the package source files?

Hi!

When you call

```julia
pkg> add /path/to/my/source/JMTk15

```

It creates a copy of the package in `~/.julia/packages`, and each version is placed in a different subdirectory (those are the five random letters). I’m guessing you have two copies there because you added to different versions of your package some time earlier.

This behavior might seem odd when you add a local package, but it is perfectly reasonable. It is the only right thing when you add a package from the network. And even makes sense locally, because once you add a package to an environment, you expect that environment to remain stable, it should not change just because you make some changes somewhere on the disk.

That being said, it often happens that you develop two or more, dependent packages simultaneously, and you explicitly want changes made in one of them reflected immediately in the other as well. You need to use the `dev` command instead of `add` in this case:

```julia
pkg> dev /path/to/my/source/JMTk15

```

This tells Julia to use the package right from the source, instead of copying it in the `~/.julia/packages` folder.

---

<div class="post-metadata">

**Author:** ![mmv](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mmv/32/26323_2.png) [@mmv](https://discourse.julialang.org/u/mmv)\
**Post date:** [May 5, 2023, 1:18pm UTC](https://discourse.julialang.org/t/using-a-locally-developed-package/98320/8 "2023-05-05T13:18:08Z")

</div>

Thanks a lot, @ HanD, for this clarification: very much appreciated.