Module Code.Typespec is not available (even inside IEx.Introspection)

Questions / Help
1

I put IEx.pry in IEx.Introspection (https://github.com/elixir-lang/elixir/blob/master/lib/iex/lib/iex/introspection.ex#L493) then started iex -S mix

I got the following error related to Code.Typespec not available.

iex(1)> IEx.Introspection.h({:proplists, :get_value})
** (UndefinedFunctionError) function Code.Typespec.fetch_specs/1 is undefined (module Code.Typespec is not available)
    Code.Typespec.fetch_specs(:proplists)
    (iex) lib/iex/introspection.ex:493: IEx.Introspection.get_spec/3
    (iex) lib/iex/introspection.ex:299: anonymous fn/5 in IEx.Introspection.h/1
    (elixir) lib/enum.ex:1899: Enum."-reduce/3-lists^foldl/2-0-"/3
    (iex) lib/iex/introspection.ex:295: IEx.Introspection.h/1

Then I tried to use Typespec inside a simple iex and that didn’t work either.

iex(1)> Code.Typespec
Code.Typespec
iex(2)> Code.Typespec.fetch_callbacks(:proplists)
** (UndefinedFunctionError) function Code.Typespec.fetch_callbacks/1 is undefined (module Code.Typespec is not available)
    Code.Typespec.fetch_callbacks(:proplists)

What did I miss?

Update

I think it’s because Code didn’t get loaded automatically. I copy the Typespec file (https://github.com/elixir-lang/elixir/blob/master/lib/elixir/lib/code/typespec.ex) and change the module name from Code.Typespec to Typespec, and put it under lib/iex/lib/iex. I also commented out alias Code.Typespec from IEx.Introspection. And now iex -S mix works because the code is able to call Typespec.fetch_specs:

iex(1)> IEx.Introspection.h({:proplists, :get_value})
Break reached: IEx.Introspection.get_spec/3 (lib/iex/introspection.ex:494)

I guess my question is what’s the correct way to load Code to IEx?

2

I looked elixir source code in my machine. There is no
Code.Typespec.fetch_specs(:proplists)
But there is
Kernel.Typespec.beam_specs(:proplists)

3

It’s in here: https://github.com/elixir-lang/elixir/blob/master/lib/elixir/lib/code/typespec.ex

It turns out I can manually load typspec in the top of IEx.Introspection and it works fine.

Code.require_file("../../../../lib/elixir/lib/code/typespec.ex", __DIR__)

5

Whats your Elixir version? There are changes to typespec code on master after last stable release, so if you are not running master that could explain it.

2 Likes
6

That makes sense! Thanks!

7

I’m using Elixir (1.6.5). It’s making sense now. Sounds like the version of elixir my machine runs is different than the version the master branch expects. Is that right?

8

Sorry my comment was wrong as @wojtekmach said there was a change in code.

9

You are totally right, I was using the elixir(1.6.5) installed on my machine, not the one built from the master branch. Use the built elixir/iex (i.e. doing ../../bin/iex -S mix inside lib/iex) and everything works like a charm. And I can see now I’m running on the 1.7-dev version:

Interactive Elixir (1.7.0-dev) - press Ctrl+C to exit (type h() ENTER for help)

Thanks!

10

See my comment above. You were not wrong. :slight_smile:
Thanks for your help! I’m glad that it all make sense now. :tada:

1 Like