From d415455ccb9789753d76f5e37a92d0dce2bca0bf Mon Sep 17 00:00:00 2001
From: kyren <kerriganw@gmail.com>
Date: Thu, 27 Jul 2017 17:16:40 -0400
Subject: [PATCH] Fix several bugs with error handling in xxx_with_traceback
 functions

In resume_with_traceback, always use the coroutine stack for error handling so
we don't miss panics, in both _with_traceback functions remove the temporary
traceback entry from the stack.
---
 src/lua.rs   |  2 +-
 src/tests.rs | 14 ++++++++++++++
 src/util.rs  | 14 +++++++++-----
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/lua.rs b/src/lua.rs
index 95d695b..3c98376 100644
--- a/src/lua.rs
+++ b/src/lua.rs
@@ -858,7 +858,7 @@ impl<'lua> Thread<'lua> {
                 }
 
                 handle_error(
-                    lua.state,
+                    thread_state,
                     resume_with_traceback(thread_state, lua.state, nargs),
                 )?;
 
diff --git a/src/tests.rs b/src/tests.rs
index b5a7ca0..bf64b6b 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -893,3 +893,17 @@ fn coroutine_from_closure() {
     let thrd: Thread = lua.eval("coroutine.create(main)", None).unwrap();
     thrd.resume::<_, ()>(()).unwrap();
 }
+
+#[test]
+#[should_panic]
+fn coroutine_panic() {
+    let lua = Lua::new();
+    let thrd_main = lua.create_function(|lua, _| {
+        // whoops, 'main' has a wrong type
+        let _coro: u32 = lua.globals().get("main").unwrap();
+        lua.pack(())
+    });
+    lua.globals().set("main", thrd_main.clone()).unwrap();
+    let thrd: Thread = lua.create_thread(thrd_main);
+    thrd.resume::<_, ()>(()).unwrap();
+}
diff --git a/src/util.rs b/src/util.rs
index 7808fd2..2cc56ed 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -381,6 +381,7 @@ pub unsafe fn pcall_with_traceback(
                 .unwrap_or_else(|_| "<could not capture traceback>")
                 .to_owned();
             push_wrapped_error(state, Error::CallbackError(traceback, Arc::new(error)));
+            ffi::lua_remove(state, -2);
         } else if !is_wrapped_panic(state, 1) {
             let s = ffi::lua_tolstring(state, 1, ptr::null_mut());
             if !s.is_null() {
@@ -388,6 +389,7 @@ pub unsafe fn pcall_with_traceback(
             } else {
                 ffi::luaL_traceback(state, state, cstr!("<unprintable lua error>"), 0);
             }
+            ffi::lua_remove(state, -2);
         }
         1
     }
@@ -408,19 +410,21 @@ pub unsafe fn resume_with_traceback(
     let res = ffi::lua_resume(state, from, nargs);
     if res != ffi::LUA_OK && res != ffi::LUA_YIELD {
         if let Some(error) = pop_wrapped_error(state) {
-            ffi::luaL_traceback(from, state, ptr::null(), 0);
-            let traceback = CStr::from_ptr(ffi::lua_tolstring(from, -1, ptr::null_mut()))
+            ffi::luaL_traceback(state, state, ptr::null(), 0);
+            let traceback = CStr::from_ptr(ffi::lua_tolstring(state, -1, ptr::null_mut()))
                 .to_str()
                 .unwrap_or_else(|_| "<could not capture traceback>")
                 .to_owned();
-            push_wrapped_error(from, Error::CallbackError(traceback, Arc::new(error)));
+            push_wrapped_error(state, Error::CallbackError(traceback, Arc::new(error)));
+            ffi::lua_remove(state, -2);
         } else if !is_wrapped_panic(state, 1) {
             let s = ffi::lua_tolstring(state, 1, ptr::null_mut());
             if !s.is_null() {
-                ffi::luaL_traceback(from, state, s, 0);
+                ffi::luaL_traceback(state, state, s, 0);
             } else {
-                ffi::luaL_traceback(from, state, cstr!("<unprintable lua error>"), 0);
+                ffi::luaL_traceback(state, state, cstr!("<unprintable lua error>"), 0);
             }
+            ffi::lua_remove(state, -2);
         }
     }
     res