Propagate original error information (#8)

lib/lua.ex

@@ -159,19 +159,16 @@ defmodule Lua do
         raise Lua.CompilerException, reason: reason
     end
   rescue
-    e in [ArgumentError, FunctionClauseError] ->
-      reraise e, __STACKTRACE__
-
-    e in [CaseClauseError, MatchError] ->
-      reraise Lua.RuntimeException, "Could not match #{inspect(e.term)}", __STACKTRACE__
-
     e in [UndefinedFunctionError] ->
       reraise Lua.RuntimeException,
               Util.format_function([e.module, e.function], e.arity),
               __STACKTRACE__
 
-    e in [ErlangError] ->
-      reraise Lua.RuntimeException, e.original, __STACKTRACE__
+    e in [Lua.RuntimeException, Lua.CompilerException] ->
+      reraise e, __STACKTRACE__
+
+    e ->
+      reraise Lua.RuntimeException, e, __STACKTRACE__
   end
 
   # Deep-set a value within a nested Lua table structure,

lib/lua/runtime_exception.ex

@@ -1,5 +1,5 @@
 defmodule Lua.RuntimeException do
-  defexception [:message]
+  defexception [:message, :original, :state]
 
   alias Lua.Util
 
@@ -29,6 +29,8 @@ defmodule Lua.RuntimeException do
     stacktrace = Luerl.New.get_stacktrace(state)
 
     %__MODULE__{
+      original: error,
+      state: state,
       message: """
       Lua runtime error: #{message}
 
@@ -37,8 +39,8 @@ defmodule Lua.RuntimeException do
     }
   end
 
-  def exception({:api_error, details, _state}) do
-    %__MODULE__{message: "Lua API error: #{details}"}
+  def exception({:api_error, details, state}) do
+    %__MODULE__{original: details, state: state, message: "Lua API error: #{details}"}
   end
 
   def exception(list) when is_list(list) do
@@ -47,6 +49,8 @@ defmodule Lua.RuntimeException do
     message = Keyword.fetch!(list, :message)
 
     %__MODULE__{
+      original: list,
+      state: nil,
       message: "Lua runtime error: #{format_function(scope, function)} failed, #{message}"
     }
   end
@@ -56,7 +60,14 @@ defmodule Lua.RuntimeException do
   end
 
   def exception(error) do
-    %__MODULE__{message: "Lua runtime error: #{inspect(error)}"}
+    message =
+      if is_exception(error) do
+        Exception.message(error)
+      else
+        inspect(error)
+      end
+
+    %__MODULE__{original: error, message: "Lua runtime error: #{message}"}
   end
 
   defp format_function([], function), do: "#{function}()"

mix.exs

@@ -2,7 +2,7 @@ defmodule Lua.MixProject do
   use Mix.Project
 
   @url "https://github.com/tv-labs/lua"
-  @version "0.0.2"
+  @version "0.0.3"
 
   def project do
     [

test/lua_test.exs

@@ -272,6 +272,16 @@ defmodule LuaTest do
         """)
       end
     end
+
+    test "arithmetic exceptions are handled" do
+      error = "Lua runtime error: bad argument in arithmetic expression"
+
+      assert_raise Lua.RuntimeException, error, fn ->
+        lua = Lua.new()
+
+        Lua.eval!(lua, "return 5 / 0")
+      end
+    end
   end
 
   describe "set!/2 and get!/2" do
@@ -404,7 +414,9 @@ defmodule LuaTest do
     end
 
     test "it cannot return tuples from Elixir", %{lua: lua} do
-      assert_raise ArgumentError, fn ->
+      error = "Lua runtime error: argument error"
+
+      assert_raise Lua.RuntimeException, error, fn ->
         Lua.eval!(lua, "return example.tuple()")
       end
     end