Elixir Compile Error

[vpfaulkner]

Hello,

I started getting a weird Elixir compile error after making any change in any file:

/app $ iex -S mix phx.server
Erlang/OTP 21 [erts-10.0] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1]

Compiling 1 file (.ex)

== Compilation error in file lib/mockit_web/controllers/mock_controller.ex ==
** (SyntaxError) lib/mockit_web/controllers/mock_controller.ex:123: unexpected token: "^@" (column 1, codepoint U+0000)
    (elixir) lib/kernel/parallel_compiler.ex:198: anonymous fn/4 in Kernel.ParallelCompiler.spawn_workers/6

If I revert the change, the error goes away.

Moreover, I noticed that I do not get that error when making the same change from within the nanobox environment (ie nanobox run followed by vim lib/mockit_web/controllers/mock_controller.ex). I am using vim in both situations.

I found a very similar issue here: https://elixirforum.com/t/error-unexpected-token-column-1-codepoint-u-0000-when-making-file-changes-with-a-code-editor/15785/4 which he resolved when he "switched to a Ubuntu 18.04 box in Vagrant and the issue no longer occurs."

I am running High Sierra on a Mac and here is my boxfile:

run.config:
  # Elixir runtime
  engine: elixir
  engine.config:
    runtime: elixir-1.6.6
    erlang_runtime: erlang-21

  # we need nodejs in development
  # ensure inotify exists for hot-code reloading
  dev_packages:
    - nodejs
    - inotify-tools

  # add node_module bins to the $PATH
  extra_path_dirs:
    - node_modules/.bin

  # enable the filesystem watcher
  fs_watch: true

deploy.config:
  # just before the new process comes online,
  # let's migrate the database
  before_live:
    web.main:
      - mix ecto.create --quiet
      - mix ecto.migrate

# add postgres as a data component
data.db:
  image: nanobox/postgresql

data.storage:
  image: nanobox/unfs:0.9

web.main:
  writable_dirs:
    - _build
  network_dirs:
    data.storage:
      - request_logs
  start: node-start mix phx.server

Any ideas?

[danhunsaker]

You'll need to switch down a version of Elixir (1.21 to 1.20, I believe) Erlang - from 21 to 20 - or from VirtualBox to Docker Native. There's a bug in the way Elixir Erlang and VirtualBox interact with each other in that specific version.

[vpfaulkner]

@danhunsaker thanks! I'm glad I asked because it might have taken me a while to figure that out.

Do you happen to know if newer Elixir versions resolved this? As far as I could tell, 1.6.6 was the latest offered by the Nanobox Elixir Engine.

[danhunsaker]

I don't, no. We have folks on the Slack server that keep better track of that, though!

[vpfaulkner]

thanks @danhunsaker I just moved the conversation there.

[vpfaulkner]

For anyone who runs into this: I downgraded from Erlang 21 to 20 and resolved the problem.

[danhunsaker]

D'oh! It was the Erlang version, not the Elixir version! Got them reversed, somehow. Edited my initial response accordingly. Sorry about the confusion!