don't try to lex sigils inside iex prompts

lib/makeup/lexers/elixir_lexer.ex

@@ -506,6 +506,20 @@ defmodule Makeup.Lexers.ElixirLexer do
     do: [{:comment, attrs, text} | postprocess_helper(tokens)]
 
   # Custom sigil lexers
+  # special case: sigil inside iex prompt
+  defp postprocess_helper([
+         {:generic_prompt, %{language: :elixir}, ["iex" | _]} = first,
+         # in the iex case, we don't get the whole sigil content in one token
+         {:string_sigil, _, ["~", _sigil_char, _separator]} = second | rest
+       ]) do
+    # we don't handle this case, because it would require some special inside
+    # and outside lexing, similar to what makeup_eex is doing
+    {extra_tokens, [end_sigil | rest]} =
+      Enum.split_while(rest, fn token -> not match?({:string_sigil, _, _}, token) end)
+
+    [first, second | extra_tokens ++ [end_sigil | postprocess_helper(rest)]]
+  end
+
   defp postprocess_helper([{:string_sigil, attrs, content} | tokens]) do
     # content is a list of the format ["~", sigil_char, separator, ... sigil_content ..., end_separator]
     sigil =

mix.exs

@@ -13,7 +13,10 @@ defmodule MakeupElixir.Mixfile do
       deps: deps(),
       package: package(),
       description: description(),
-      aliases: aliases()
+      aliases: aliases(),
+      test_ignore_filters: [
+        &String.starts_with?(&1, "test/generators/")
+      ]
     ]
   end
 

test/makeup/lexers/elixir_lexer/elixir_lexer_sigil_lexer_test.exs

@@ -20,5 +20,29 @@ defmodule ElixirLexerSigilLexerTest do
     after
       Application.put_env(:makeup_elixir, :sigil_lexers, %{})
     end
+
+    test "does not lex inside iex prompts" do
+      # does not exist, but should also not be invoked
+      Makeup.Lexers.ElixirLexer.register_sigil_lexer("PY", DoesNotExist, foo: :bar)
+
+      # if it tried to use the sigil lexer, it would crash
+      assert lex("""
+             iex> import Pythonx
+             iex> x = 1
+             iex> ~PY\"""
+             ...> y = 10
+             ...> x + y
+             ...> \"""
+             #Pythonx.Object<
+               11
+             >
+             iex> x
+             1
+             iex> y
+             #Pythonx.Object<
+               10
+             >
+             """)
+    end
   end
 end