Use inspect/1 to safely encode bad binary samples (#1121)

* Use inspect to safely encode bad binary samples

* Tweak test to better represent failure state

* Only inspect when necessary

lib/absinthe/phase/parse.ex

@@ -104,7 +104,8 @@ defmodule Absinthe.Phase.Parse do
  @spec format_raw_parse_error({:lexer, String.t(), {line :: pos_integer, column :: pos_integer}}) ::
  Phase.Error.t()
  defp format_raw_parse_error({:lexer, rest, {line, column}}) do
- sample = String.slice(rest, 0, 10)
+ sample_slice = String.slice(rest, 0, 10)
+ sample = if String.valid?(sample_slice), do: sample_slice, else: inspect(sample_slice)
 
  message = "Parsing failed at `#{sample}`"
  %Phase.Error{message: message, locations: [%{line: line, column: column}], phase: __MODULE__}

test/absinthe/phase/parse_test.exs

@@ -43,6 +43,21 @@ defmodule Absinthe.Phase.ParseTest do
  ] == bp.execution.validation_errors
  end
 
+ @graphql "test bad string" <> <<223>> <> "error"
+ test "coerces non-string binaries to strings" do
+ assert {:error, bp} = Absinthe.Phase.Parse.run(@graphql)
+
+ [parse_error] = bp.execution.validation_errors
+ assert String.valid?(parse_error.message)
+
+ assert %Absinthe.Phase.Error{
+ extra: %{},
+ locations: [%{column: 16, line: 1}],
+ message: "Parsing failed at `<<223, 101, 114, 114, 111, 114>>`",
+ phase: Absinthe.Phase.Parse
+ } == parse_error
+ end
+
  @graphql ";"
  test "should provide sample of parsing failure on very short query strings" do
  assert {:error, bp} = Absinthe.Phase.Parse.run(@graphql, jump_phases: false)