# How to find an indirect dependency inside a module?
**URL:** https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559
**Category:** Internals & Design
**Tags:** pkg
**Created:** [June 10, 2022, 11:03am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559 "2022-06-10T11:03:55Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@rikh](https://discourse.julialang.org/u/rikh)
#### Post date: [June 10, 2022, 11:03am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/1 "2022-06-10T11:03:56Z")
Say that I have a package `Foo` with direct and indirect dependencies `A <- B <- C` (i.e., A loads B and B loads C) and my package looks like
```julia
module Foo
using A
[...]
end
```
also say that I’m given a type `T` in `C` printed as `C.T` as a `String`.
What is now the easiest way to find `C`? Because if I do `@show C`, then I get a “C undefined” error. I can do `@show A.B.C`, but then I first need to find it
The reason that I ask this is because I’m experimenting a bit with the `--trace-compile` flag.
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [June 10, 2022, 11:06am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/2 "2022-06-10T11:06:03Z")
```julia
help> parentmodule
[...]
──────────────────────────────────────────────────────────────────────
parentmodule(t::DataType) -> Module
Determine the module containing the definition of a (potentially
UnionAll-wrapped) DataType.
Examples
≡≡≡≡≡≡≡≡≡≡
julia> module Foo
struct Int end
end
Foo
julia> parentmodule(Int)
Core
julia> parentmodule(Foo.Int)
Foo
[...]
```
---
### Author:  [@rikh](https://discourse.julialang.org/u/rikh)
#### Post date: [June 10, 2022, 11:09am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/3 "2022-06-10T11:09:08Z")
Close, but what if I have a String object and not a DataType?
---
### Author:  [@rikh](https://discourse.julialang.org/u/rikh)
#### Post date: [June 10, 2022, 11:12am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/4 "2022-06-10T11:12:03Z")
Ah. Think that I got it via `Base.loaded_modules`
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [June 10, 2022, 11:12am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/5 "2022-06-10T11:12:21Z")
I’d first question why you only have that as a string and see if you can get the type directly instead, but otherwise `parentmodule(eval(Meta.parse(...)))`?
Getting a proper type object first is of course preferrable - though your example with `@show C` implies that you want to already have some kind of reference to a type in the first place, right?
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [June 10, 2022, 11:13am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/6 "2022-06-10T11:13:58Z")
> [@rikh](#):
>
> Ah. Think that I got it via `Base.loaded_modules`
That looks like an internal variable to me - I’d look through the `Pkg` API for querying what dependencies the current active project has instead.
---
### Author:  [@rikh](https://discourse.julialang.org/u/rikh)
#### Post date: [June 10, 2022, 11:15am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/7 "2022-06-10T11:15:34Z")
> [@Sukera](#):
>
> Getting a proper type object first is of course preferrable - though your example with `@show C` implies that you want to already have some kind of reference to a type in the first place, right?
Yeah true. My example wasn’t the clearest. I didn’t have a ref yet.
> [@Sukera](#):
>
> I’d first question why you only have that as a string and see if you can get the type directly instead, but otherwise `parentmodule(eval(Meta.parse(...)))`?
Because that is the output of `julia --trace-compile=traces.jl [...]`.
> [@Sukera](#):
>
> That looks like an internal variable to me - I’d look through the `Pkg` API for querying what dependencies the current active project has instead.
Check. I’ll try that
---
### Author:  [@Sukera](https://discourse.julialang.org/u/Sukera)
#### Post date: [June 10, 2022, 11:45am UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/8 "2022-06-10T11:45:03Z")
> [@rikh](#):
>
> Because that is the output of `julia --trace-compile=traces.jl [...]`.
Ah, I see 🤔 Sadly, that part lives in C (check `src/gf.c:2013`, the function is called `record_precompile_statement` and it’s called during compilation), so getting a type out there is difficult… Then I don’t think there’s a way around `eval(Meta.parse(...))`.
I do wish the compiler would expose some sort of diagnostics interface, for interacting with these sorts of things programmatically. Other kinds of diagnostics I’d be interested in would be getting a log of inlining/vectorization/etc. decisions and the reasoning why something was (not) done, without having to reparse emitted LLVM IR.
---
### Author:  [@rikh](https://discourse.julialang.org/u/rikh)
#### Post date: [June 10, 2022, 12:08pm UTC](https://discourse.julialang.org/t/how-to-find-an-indirect-dependency-inside-a-module/82559/9 "2022-06-10T12:08:06Z")
> [@Sukera](#):
>
> I do wish the compiler would expose some sort of diagnostics interface, for interacting with these sorts of things programmatically. Other kinds of diagnostics I’d be interested in would be getting a log of inlining/vectorization/etc. decisions and the reasoning why something was (not) done, without having to reparse emitted LLVM IR.
Agreed