From 66503ecccd41260d9d73cbae89cef1f73addd0d4 Mon Sep 17 00:00:00 2001
From: Samuel Just <sjust@redhat.com>
Date: Fri, 17 Jan 2020 13:04:30 -0800
Subject: [PATCH] crimson/common/errorator: restrict all_same_way to valid
 types

As with pass_further/discard_all, we don't want the returned handler
to work on types outside of the errorator at all.  Otherwise, the
handler will transparently apply to any error.

Signed-off-by: Samuel Just <sjust@redhat.com>
---
 src/crimson/common/errorator.h | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/crimson/common/errorator.h b/src/crimson/common/errorator.h
index 3750b67360a50..b57c8407e5cee 100644
--- a/src/crimson/common/errorator.h
+++ b/src/crimson/common/errorator.h
@@ -635,6 +635,21 @@ private:
   template <typename T>
   using EnableIf = typename std::enable_if<contains_once_v<std::decay_t<T>>, Enabler>::type;
 
+  template <typename ErrorFunc>
+  struct all_same_way_t {
+    ErrorFunc func;
+    all_same_way_t(ErrorFunc &&error_func)
+      : func(std::forward<ErrorFunc>(error_func)) {}
+
+    template <typename ErrorT, EnableIf<ErrorT>...>
+    decltype(auto) operator()(ErrorT&& e) {
+      using decayed_t = std::decay_t<decltype(e)>;
+      auto&& handler =
+        decayed_t::error_t::handle(std::forward<ErrorFunc>(func));
+      return std::invoke(std::move(handler), std::forward<ErrorT>(e));
+    }
+  };
+
 public:
   // HACK: `errorated_future_marker` and `_future` is just a hack to
   // specialize `seastar::futurize` for category of class templates:
@@ -667,14 +682,7 @@ public:
 
   template <class ErrorFunc>
   static decltype(auto) all_same_way(ErrorFunc&& error_func) {
-    return [
-      error_func = std::forward<ErrorFunc>(error_func)
-    ] (auto&& e) mutable -> decltype(auto) {
-      using decayed_t = std::decay_t<decltype(e)>;
-      auto&& handler =
-        decayed_t::error_t::handle(std::forward<ErrorFunc>(error_func));
-      return std::invoke(std::move(handler), std::forward<decltype(e)>(e));
-    };
+    return all_same_way_t<ErrorFunc>{std::forward<ErrorFunc>(error_func)};
   };
 
   // get a new errorator by extending current one with new error
-- 
2.39.5