How to find the path of a package in Julia?

Question

I am trying to find the path to a specific package in Julia. I do not know exactly where it is and I want to use the appropriate path. Is there a function that does this in Juli

Answer 1

Once you have it loaded yuou have a Module object.

If you have module object you can use pathof to find it.

julia> using DataFrames

julia> pathof(DataFrames)
"/Users/oxinabox/.julia/packages/DataFrames/cdZCk/src/DataFrames.jl"

julia> pathof(DataFrames.PooledArrays)
"/Users/oxinabox/.julia/packages/PooledArrays/yiLq3/src/PooledArrays.jl"

If we were a bit broader and wanted the path to a module that wasn't a package, but was either loaded directly, or a submodule, than pathof won't work.

For example LibPQ.jl has a Errors submodule

julia> using LibPQ

julia> pathof(LibPQ)
"/Users/oxinabox/.julia/packages/LibPQ/SFs6f/src/LibPQ.jl"

julia> typeof(LibPQ.Errors)
Module

julia> pathof(LibPQ.Errors)

the output was nothing.

This is as per the pathof documentation

Return the path of the m.jl file that was used to import module m, or nothing if m was not imported from a package.

If you want to track that down there is a trick. All modules in julia (except baremodules) automatically contain a defination for there own eval function. We can look up the location of this function from the method table.

julia> module_file(modu) = String(first(methods(getfield(modu, :eval))).file)
module_file (generic function with 1 method)

julia> module_file(LibPQ)
"/Users/oxinabox/.julia/packages/LibPQ/SFs6f/src/LibPQ.jl"

julia> module_file(LibPQ.Errors)
"/Users/oxinabox/.julia/packages/LibPQ/SFs6f/src/exceptions.jl

Other than baremodules and modules that are not packages, there is one other case where they disagree.

pathof resolves module location via the Manifest. If you change the manfiest after loading a module, then the module that is loaded will still actually refer to the old location, but the Manifest, and thus pathof will think it is at the new location.

(11) pkg> dev --local LibPQ
    Cloning git-repo `https://github.com/invenia/LibPQ.jl.git`
  Resolving package versions...
Updating `~/temp/11/Project.toml`
  [194296ae] ~ LibPQ v1.5.0 ⇒ v1.5.0 `dev/LibPQ`
Updating `~/temp/11/Manifest.toml`
  [194296ae] ~ LibPQ v1.5.0 ⇒ v1.5.0 `dev/LibPQ`
   Building LibPQ → `~/temp/11/dev/LibPQ/deps/build.log`

julia> pathof(LibPQ)
"/Users/oxinabox/temp/11/dev/LibPQ/src/LibPQ.jl"

julia> module_file(LibPQ)
"/Users/oxinabox/.julia/packages/LibPQ/SFs6f/src/LibPQ.jl"

pathof is giving what is arguably the wrong answer (this is true for julia 1.5 at least I suspect it might change in the future.) but module_file, because it looks at what code is actually loaded and records that location at load time, gives the right answer.

Answer 2

Julia's standard library (Base) provides a find_package function which works as follows:

julia> Base.find_package("Random")
"/Applications/Julia-1.3.app/Contents/Resources/julia/share/julia/stdlib/v1.3/Random/src/Random.jl"

julia> Base.find_package("JSON")
"/Users/logankilpatrick/.julia/packages/JSON/d89fA/src/JSON.jl"

Answer 3

You can use pathof to find the location of an imported module (and package if the module was in a package)

julia> using Random

julia> pathof(Random)
"C:\\Julia-1.4.1\\share\\julia\\stdlib\\v1.4\\Random\\src\\Random.jl"