From a4312c1e04f33fd8b5f2b2649ae6aff6d31e763d Mon Sep 17 00:00:00 2001
From: "Nicolas \"Pixel\" Noble" <pixel@nobis-crew.org>
Date: Mon, 5 Aug 2013 09:35:31 +0200
Subject: Improving the output of GeneralExceptions in Lua; also you can't call
 lua_error on a yielded co-routine.

---
 includes/BLua.h |  3 ++-
 src/BLua.cc     | 25 +++++++++++++++++++++----
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/includes/BLua.h b/includes/BLua.h
index 40e89bd..a464a77 100644
--- a/includes/BLua.h
+++ b/includes/BLua.h
@@ -133,7 +133,7 @@ class Lua {
     int gettop() { return lua_gettop(L); }
     void getglobal(const char * name) throw (GeneralException);
     void pushLuaContext();
-    void error(const char * msg);
+    void error(const char * msg) throw (GeneralException);
     void error(const String & msg) { error(msg.to_charp()); }
 
     int type(int i = -1) { return lua_type(L, i); }
@@ -197,6 +197,7 @@ class Lua {
     void dumpvars_r(IO<Handle> out, int idx, int depth = 0) throw (GeneralException);
     bool resumeC();
     bool yieldC() throw (GeneralException);
+    void processException(GeneralException & e);
 
     lua_State * L;
 
diff --git a/src/BLua.cc b/src/BLua.cc
index 48e77d4..bed33a0 100644
--- a/src/BLua.cc
+++ b/src/BLua.cc
@@ -257,7 +257,7 @@ int Balau::LuaStatics::callwrap(lua_State * __L, lua_CFunction func) {
         L.error("The C callback from Lua has thrown an EAgain - you can't do that, you have to wrap it using Lua::yield. The application will now crash, because this task will stop, but the event in the EAgain will later try to wake it up.");
     }
     catch (GeneralException & e) {
-        L.error(String("GeneralException: ") + e.getMsg());
+        L.processException(e);
     }
 // LuaJIT sucks sometime.
 //    catch (...) {
@@ -479,10 +479,17 @@ void Balau::Lua::pushLuaContext() {
     } while (!got_error);
 }
 
-void Balau::Lua::error(const char * msg) {
+void Balau::Lua::error(const char * msg) throw (GeneralException) {
     push(msg);
 
-    lua_error(L);
+    if (yielded()) {
+        pushLuaContext();
+        showerror();
+
+        throw LuaException("Runtime error while running yielded C code.");
+    } else {
+        lua_error(L);
+    }
 }
 
 bool Balau::Lua::isobject(int i) {
@@ -845,7 +852,7 @@ bool Balau::Lua::resumeC() {
         yieldedAgain = true;
     }
     catch (Balau::GeneralException & e) {
-        error(String("GeneralException: ") + e.getMsg());
+        processException(e);
     }
     if (!yieldedAgain)
         resume(nargs);
@@ -882,6 +889,16 @@ bool Balau::Lua::yieldC() throw (GeneralException) {
     return yieldC();
 }
 
+void Balau::Lua::processException(GeneralException & e) {
+    const char * details = e.getDetails();
+    if (details)
+        push(details);
+    auto trace = e.getTrace();
+    for (String & str : trace)
+        push(str);
+    error(String("General Exception: ") + e.getMsg());
+}
+
 void Balau::Lua::showstack(int level) {
     int n = lua_gettop(L);
     int i;
-- 
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