Can't use local function scrub_params/1 inside Endpoint

[dmorneau]

Environment

• Elixir version (elixir -v): 1.10.4
• Erlang/OTP version (erl): 23
• Sentry version (mix deps): 8.0.0-rc2
• Operating system: macOS
• Is this an umbrella application?: no
• Release type (Distillery, mix release, Mix, etc.): mix release

Description

This sample code from the 8.0.0-rc2 doc causes a compile error if I try to use it in my app:

use Sentry.PlugContext, body_scrubber: &scrub_params/1

...even though there is a scrub_params/1 function defined within the module. This used to work fine when using Sentry.Plug within the Router, with locally defined functions.

Expected Behavior

If I define a local function inside the Endpoint module, then pass it to Sentry.PlugContext, I would expect it to compile fine.

Actual Behavior

== Compilation error in file lib/myapp_web/endpoint.ex ==
** (CompileError) lib/myapp_web/endpoint.ex:68: undefined function scrub_params/1
    (stdlib 3.13) lists.erl:1354: :lists.mapfoldl/3
    (stdlib 3.13) lists.erl:1355: :lists.mapfoldl/3
    (stdlib 3.13) lists.erl:1354: :lists.mapfoldl/3
    (stdlib 3.13) lists.erl:1355: :lists.mapfoldl/3
    (stdlib 3.13) lists.erl:1354: :lists.mapfoldl/3
    (stdlib 3.13) lists.erl:1355: :lists.mapfoldl/3
    (elixir 1.10.4) expanding macro: Kernel.@/1
    lib/myapp_web/endpoint.ex:66: MyAppWeb.Endpoint (module)
    (plug 1.10.3) expanding macro: Plug.Builder.plug/2

Steps to Reproduce

In a Phoenix app, define this function inside the endpoint module:

  def scrub_params(conn) do
    Enum.into(conn.params, %{})
    |> Map.drop(["secret"])
  end

Then somewhere else in the endpoint use it in PlugContext:

  plug Sentry.PlugContext, body_scrubber: &scrub_params/1

It doesn't matter if the function is defined before or after the plug.

Workaround

Using a tuple works:

  plug Sentry.PlugContext, body_scrubber: {__MODULE__, :scrub_params}

[mitchellhenke]

Thanks for reporting. I've updated and re-published the docs for rc2 and plan on doing a general release next week 🙂