add pathof(::Module) (#28310)

NEWS.md

@@ -549,6 +549,8 @@ Library improvements
  * `Char` is now a subtype of `AbstractChar`, and most of the functions that
  take character arguments now accept any `AbstractChar` ([#26286]).
 
+ * `pathof(module)` returns the path a module was imported from ([#28310]).
+
  * `bytes2hex` now accepts an optional `io` argument to output to a hexadecimal stream
  without allocating a `String` first ([#27121]).
 

base/exports.jl

@@ -739,6 +739,7 @@ export
  methods,
  nameof,
  parentmodule,
+ pathof,
  names,
  which,
  @isdefined,

base/loading.jl

@@ -249,6 +249,18 @@ function locate_package(pkg::PkgId)::Union{Nothing,String}
 end
 locate_package(::Nothing) = nothing
 
+"""
+ pathof(m::Module)
+
+Return the path of `m.jl` file that was used to `import` module `m`,
+or `nothing` if `m` was not imported from a package.
+"""
+function pathof(m::Module)
+ pkgid = get(Base.module_keys, m, nothing)
+ pkgid === nothing && return nothing
+ return Base.locate_package(pkgid)
+end
+
 ## generic project & manifest API ##
 
 const project_names = ("JuliaProject.toml", "Project.toml")

doc/src/base/base.md

@@ -332,6 +332,7 @@ Base.AsyncCondition(::Function)
 ```@docs
 Base.nameof(::Module)
 Base.parentmodule
+Base.pathof(::Module)
 Base.moduleroot
 Base.@__MODULE__
 Base.fullname

stdlib/Pkg/src/API.jl

@@ -432,13 +432,13 @@ function clone(url::String, name::String = "")
  develop(ctx, [Pkg.REPLMode.parse_package(url; add_or_develop=true)])
 end
 
-function dir(pkg::String, paths::String...)
- @warn "Pkg.dir is only kept for legacy CI script reasons" maxlog=1
+function dir(pkg::String, paths::AbstractString...)
+ @warn "`Pkg.dir(pkgname, paths...)` is deprecated; instead, do `import $pkg; joinpath(dirname(pathof($pkg)), \"..\", paths...)`." maxlog=1
  pkgid = Base.identify_package(pkg)
- pkgid == nothing && return nothing
+ pkgid === nothing && return nothing
  path = Base.locate_package(pkgid)
- pkgid == nothing && return nothing
- return joinpath(abspath(path, "..", "..", paths...))
+ path === nothing && return nothing
+ return abspath(path, "..", "..", paths...)
 end
 
 precompile() = precompile(Context())

test/loading.jl

@@ -218,6 +218,8 @@ Base.ACTIVE_PROJECT[] = nothing
  end
 end
 
+module NotPkgModule; end
+
 @testset "project & manifest import" begin
  @test !@isdefined Foo
  @test !@isdefined Bar
@@ -254,6 +256,12 @@ end
  end
  end
  @test Foo.which == "path"
+
+ @testset "pathof" begin
+ @test pathof(Foo) == normpath(abspath(@__DIR__, "project/deps/Foo1/src/Foo.jl"))
+ @test pathof(NotPkgModule) === nothing
+ end
+
 end
 
 ## systematic generation of test environments ##