Better error reporting for invalid ANSI escape sequences

Author: yrashk

lib/elixir/lib/io/ansi.ex

@@ -141,6 +141,11 @@ defmodule IO.ANSI do
     escape_sequence(rest)
   end
 
+  defp escape_sequence(other) do
+    [spec|_] = String.split(other, %r/(,|\})/)
+    raise ArgumentError, message: "invalid ANSI sequence specification: #{spec}"
+  end
+
   @doc %B"""
   Escapes a string coverting named ANSI sequences into actual ANSI codes.
 

lib/elixir/test/elixir/io/ansi_test.exs

@@ -33,4 +33,13 @@ defmodule IO.ANSITest do
   test :noop do
     assert IO.ANSI.escape("") == ""
   end
+
+  test :invalid do
+    assert_raise ArgumentError, "invalid ANSI sequence specification: brigh", fn ->
+      IO.ANSI.escape("%{brigh}, yes")
+    end
+    assert_raise ArgumentError, "invalid ANSI sequence specification: brigh", fn ->
+      IO.ANSI.escape("%{brigh,red}, yes")
+    end
+  end
 end