Debugging `mix deps.get`?

rlipscombe · November 29, 2019, 1:44pm

I want to find out what mix deps.get is doing (see Compiling Erlang project, but transitive dependency uses mix.exs with wrong language option). Is this possible? How do I do it?

(Assume I know how to use dbg, if that helps).

invacto · December 4, 2019, 10:56am

Is it the source code you’re looking for?
In that case, on most hexdocs pages there is an icon on the top right “<>” which takes you to the code of that module.

Here is the source code for the mix deps.get command:

github.com

elixir-lang/elixir/blob/v1.9.4/lib/mix/lib/mix/tasks/deps.get.ex#L1


defmodule Mix.Tasks.Deps.Get do
  use Mix.Task


  @shortdoc "Gets all out of date dependencies"


  @moduledoc """
  Gets all out of date dependencies, i.e. dependencies
  that are not available or have an invalid lock.


  ## Command line options

EDIT: If you’re looking to see what it’s doing in your project I’d suggest making a custom mix task to which you copy the code from deps.get and then debug it from there

rlipscombe · December 4, 2019, 12:23pm

No; I know where the source code is.

I want to attach a debugger to it.

I’d suggest making a custom mix task to which you copy the code from deps.get and then debug it from there

I pulled the latest Elixir source and stuck some extra logging in it. printf-debugging ftw.

I guess my underlying question is this: given iex -S some_command, how does iex -S work, and how can I get in there early enough to attach a debugger or trace?