don't swallow stack traces

README.md

@@ -94,7 +94,7 @@ result = retry with: constant_backoff(100) |> Stream.take(10) do
 after
   result -> result
 else
-  e when is_exception(e) -> raise e
+  {e, stacktrace} when is_exception(e) -> reraise e, stacktrace
   e -> e
 end
 ```

lib/retry.ex

@@ -47,7 +47,7 @@ defmodule Retry do
       default: [
         else:
           quote do
-            e when is_exception(e) -> raise e
+            {e, stacktrace} when is_exception(e) -> reraise e, stacktrace
             e -> e
           end,
         after:
@@ -162,8 +162,8 @@ defmodule Retry do
         fun.()
       end)
       |> case do
-        {:exception, e} ->
-          case e do
+        {:exception, e, stacktrace} ->
+          case {e, stacktrace} do
             unquote(else_clause)
           end
 
@@ -336,7 +336,7 @@ defmodule Retry do
         rescue
           e ->
             if e.__struct__ in unquote(exceptions) do
-              {:cont, {:exception, e}}
+              {:cont, {:exception, e, __STACKTRACE__}}
             else
               reraise e, __STACKTRACE__
             end

test/retry_test.exs

@@ -9,6 +9,23 @@ defmodule RetryTest do
   defmodule(CustomError, do: defexception(message: "custom error!"))
 
   describe "retry" do
+    defp boom, do: raise "boom"
+
+    test "keeps correct stack trace" do
+      e =
+        try do
+          retry with: [1] do
+            boom()
+          end
+        rescue
+          e ->
+            Exception.format(:error, e, __STACKTRACE__)
+        end
+
+      assert e =~ "(RuntimeError) boom"
+      assert e =~ "test/retry_test.exs:12: RetryTest.boom"
+    end
+
     test "retries execution for specified attempts when result is error tuple" do
       {elapsed, _} =
         :timer.tc(fn ->
@@ -94,7 +111,7 @@ defmodule RetryTest do
             after
               _ -> :ok
             else
-              error -> raise error
+              {error, _} -> raise error
             end
           end
         end)
@@ -113,7 +130,7 @@ defmodule RetryTest do
             after
               _ -> :ok
             else
-              error -> raise error
+              {error, _} -> raise error
             end
           end
         end)