Is there any way to build package dependency tree in julia-lang? - julia

Question

Using npm list will show a tree of installed packages, versions and relations:
Although Julia package management is differ (e.g normally no duplicate copy of a package exists), But is there any way to:
Know why one package have been installed?
or build a package dependency tree.

Answer 1

I don't think there's a simple function, but it shouldn't be too hard to do with these two functions:
julia> Pkg.dependents("Cairo")
10-element Array{AbstractString,1}:
"Tk"
"Gtk"
"Mamba"
"Drawing"
"GtkUtilities"
"ProfileView"
"Brim"
"Winston"
"EcologicalNetwork"
"VennEuler"
julia> Pkg.installed()
Dict{ASCIIString,VersionNumber} with 119 entries:
"Libz" => v"0.0.2"
"Gtk" => v"0.9.3"
"Interact" => v"0.3.0"
"ForwardDiff" => v"0.1.4"
"Benchmark" => v"0.1.0"
"AxisAlgorithms" => v"0.1.4"
"Cairo" => v"0.2.31+"
"HttpParser" => v"0.1.1"
"DataFrames" => v"0.6.10"
"Requests" => v"0.3.4"
"QuartzImageIO" => v"0.1.0+"
"Markdown" => v"0.3.0"
"Requires" => v"0.2.2"
"ArgParse" => v"0.3.0"
⋮ => ⋮

Answer 2

simple code bellow will printout the requires-by result for a package:
whorequires(pkgname) = whorequires(pkgname, 0);
function whorequires(pkgname, i)
deps = Pkg.dependents(pkgname);
[print('-') for j=1:i];
println(pkgname);
length(deps) > 0 && [whorequires(dep,i+1) for dep in deps];
end
julia> whorequires("JuliaParser");
JuliaParser
-CodeTools
--Atom
-ASTInterpreter
--Gallium
-Jewel
EDIT (to cover issue commented by #amrods)
whorequires(pkgname) = whorequires(pkgname, 0, Dict{ASCIIString,Vector{ASCIIString}}());
function whorequires(pkgname, i, m)
[print('-') for j=1:i];
if (haskey(m,pkgname))
println("$pkgname *[duplicated]* is required by ", length(m[pkgname]), " packages");
else
println(pkgname);
m[pkgname] = Pkg.dependents(pkgname);
if (length(m[pkgname]) > 0)
for dep in m[pkgname]
whorequires(dep,i+1,m);
end
end
end
end

Answer 3

There is a package, although not registered, which does this: https://github.com/peng1999/PkgDependency.jl
It's quite straightforward to use
pkg> add https://github.com/peng1999/PkgDependency.jl
julia> using PkgDependency
julia> PkgDependency.tree("HTTP")
HTTP v0.9.13
NetworkOptions v1.2.0
IniFile v0.5.0
URIs v1.3.0
MbedTLS v1.0.3
MbedTLS_jll v2.16.8+1
JLLWrappers v1.3.0
Preferences v1.2.2
TOML v1.0.3
Artifacts v1.3.0
It relies on a new (>1.4) experimental API, which can be used on its own to list (direct) dependencies, but it's quite ugly:
julia> using Pkg
julia> Pkg.dependencies()[Pkg.project().dependencies["HTTP"]].dependencies
Dict{String, Base.UUID} with 5 entries:
"Dates" => UUID("ade2ca70-3891-5945-98fb-dc099432e06a")
"Base64" => UUID("2a0f44e3-6c83-55bd-87e4-b1978d98bd5f")
"Sockets" => UUID("6462fe0b-24de-5631-8697-dd941f90decc")
"IniFile" => UUID("83e8ac13-25f8-5344-8a64-a9f2b223428f")
"MbedTLS" => UUID("739be429-bea8-5141-9913-cc70e7f3736d")
If you only want the list for dependencies of the currently active project, then Pkg.project().dependencies is enough.
I've opened a Pkg.jl issue to discuss this here.