Add redact errors option in normal mode

lib/csv.ex

@@ -38,6 +38,10 @@ defmodule CSV do
       length. Defaults to `false`.
   * `:unescape_formulas`    – When set to `true`, will remove formula escaping
       inserted to prevent [CSV Injection](https://owasp.org/www-community/attacks/CSV_Injection).
+  * `:redact_errors`        – When set to `true`, will redact csv data in
+      message output of errors. This is to address scenarios where errors are
+      propagated in a stream and accidental logging of sensitive data needs
+      to be prevented. Defaults to `false`.
 
   ## Examples
 
@@ -149,7 +153,7 @@ defmodule CSV do
           | {:escape_character, char()}
           | {:escape_max_lines, integer()}
 
-  @spec decode(Enumerable.t(), [decode_options()]) :: Enumerable.t()
+  @spec decode(Enumerable.t(), [decode_options() | {:redact_errors, boolean()}]) :: Enumerable.t()
   def decode(stream, options \\ []) do
     stream |> Decoder.decode(options) |> inline_errors!(options)
   end
@@ -305,15 +309,16 @@ defmodule CSV do
 
   defp inline_errors!(stream, options) do
     escape_max_lines = options |> Keyword.get(:escape_max_lines, @escape_max_lines)
+    redact_errors = options |> Keyword.get(:redact_errors, false)
 
-    stream |> Stream.map(&yield_or_inline!(&1, escape_max_lines))
+    stream |> Stream.map(&yield_or_inline!(&1, escape_max_lines, redact_errors))
   end
 
-  defp yield_or_inline!({:error, mod, args}, _) do
-    {:error, mod.exception(args ++ [mode: :normal, unredact: true]).message}
+  defp yield_or_inline!({:error, mod, args}, _, redact_errors) do
+    {:error, mod.exception(args ++ [mode: :normal, unredact: !redact_errors]).message}
   end
 
-  defp yield_or_inline!(value, _), do: value
+  defp yield_or_inline!(value, _, _), do: value
 
   @doc """
   Encode a table stream into a stream of RFC 4180 compliant CSV lines for

test/csv_exceptions_test.exs

@@ -31,6 +31,19 @@ defmodule CSVExceptionsTest do
            ]
   end
 
+  test "decodes in normal mode redacting error messages when configured" do
+    stream = ~w(a,be a" c,d) |> to_line_stream
+    result = CSV.decode(stream, redact_errors: true) |> Enum.to_list()
+
+    assert result == [
+             ok: ~w(a be),
+             error:
+               "Stray escape character on line 2:\n\n**redacted**\n\n" <>
+                 "This error often happens when the wrong separator or escape character has been applied.\n",
+             ok: ~w(c d)
+           ]
+  end
+
   test "decodes in strict mode raising errors" do
     stream = ~w(a,be a c,d) |> to_line_stream