fix(timeouts) failing errors handlers in Lua 5.1

see underlying bug: keplerproject/coxpcall#18

Makefile

@@ -60,6 +60,7 @@ test: certs
 	$(LUA) $(DELIM) $(PKGPATH) tests/starve.lua
 	$(LUA) $(DELIM) $(PKGPATH) tests/tcptimeout.lua
 	$(LUA) $(DELIM) $(PKGPATH) tests/timer.lua
+	$(LUA) $(DELIM) $(PKGPATH) tests/timeout_errors.lua
 	$(LUA) $(DELIM) $(PKGPATH) tests/tls-sni.lua
 	$(LUA) $(DELIM) $(PKGPATH) tests/udptimeout.lua
 	$(LUA) $(DELIM)

docs/index.html

@@ -100,6 +100,13 @@ <h2><a name="dependencies"></a>Dependencies</h2>
 <h2><a name="history"></a>History</h2>
 
 <dl class="history">
+    <dt><strong>Copas 4.3.x</strong> [unreleased]</dt>
+	<dd><ul>
+        <li>Fix: error handler for timeouts. Underlying <a href="https://github.com/keplerproject/coxpcall/issues/18">
+        bug is in coxpcall</a>, and hence this only applies to PuC Lua 5.1.
+        </li>
+    </ul></dd>
+
     <dt><strong>Copas 4.3.1</strong> [21/Sep/2022]</dt>
 	<dd><ul>
         <li>Fix: with Lua 5.1 the timeouts would resume the wrapped (by coxpcall)

src/copas.lua

@@ -1236,13 +1236,16 @@ end
 
 do
   local timeout_register = setmetatable({}, { __mode = "k" })
+  local time_out_thread
   local timerwheel = require("timerwheel").new({
       precision = TIMEOUT_PRECISION,                -- timeout precision 100ms
       ringsize = math.floor(60/TIMEOUT_PRECISION),  -- ring size 1 minute
-      err_handler = function(...) return _deferror(...) end,
+      err_handler = function(err)
+        return _deferror(err, time_out_thread)
+      end,
     })
 
-  copas.addnamedthread("copas_core_timer", function()
+  time_out_thread = copas.addnamedthread("copas_core_timer", function()
     while true do
       copas.sleep(TIMEOUT_PRECISION)
       timerwheel:step()

tests/errhandlers.lua

@@ -68,7 +68,7 @@ if _VERSION ~= "Lua 5.1" then
 
     print = old_print   --luacheck: ignore
 
-    assert(msg:find("errhandlers%.lua:%d-: hi there! %(coroutine: nil, socket: nil%)"), "got:\n"..msg)
+    assert(msg:find("errhandlers%.lua:%d-: hi there! %(coroutine: copas_core_timer, socket: nil%)"), "got:\n"..msg)
     assert(msg:find("stack traceback:.+errhandlers%.lua"), "got:\n"..msg)
   end
 end

tests/timeout_errors.lua

@@ -0,0 +1,50 @@
+-- Tests Copas timeout mnechanism, when a timeout handler errors out
+--
+-- Run the test file, it should exit successfully without hanging.
+
+-- make sure we are pointing to the local copas first
+package.path = string.format("../src/?.lua;%s", package.path)
+local copas = require("copas")
+
+
+local tests = {}
+
+
+function tests.error_on_timeout()
+  local err_received
+
+  copas.addthread(function()
+    copas.setErrorHandler(function(err, coro, skt)
+      err_received = err
+    end, true)
+    print "setting timeout in 0.1 seconds"
+    copas.timeout(0.1, function()
+      print "throwing an error now..."
+      error("oops...")
+    end)
+    print "going to sleep for 1 second"
+    copas.sleep(1)
+
+    if not (err_received or ""):find("oops...", 1, true) then
+      print("expected to find the error string 'oops...', but got: " .. tostring(err_received))
+      os.exit(1)
+    end
+  end)
+
+  copas.loop()
+end
+
+
+
+
+
+-- test "framework"
+for name, test in pairs(tests) do
+  print("testing: "..tostring(name))
+  local status, err = pcall(test)
+  if not status then
+    error(err)
+  end
+end
+
+print("[✓] all tests completed successuly")