From f5f119f51a0241f8bbb1f8710fb37119b375539b Mon Sep 17 00:00:00 2001
From: osch <oliver at luced de>
Date: Tue, 4 Sep 2018 21:33:12 +0200
Subject: avoid NULL as parameter to fputs()

---
 .travis.yml         |  1 +
 appveyor.yml        |  1 +
 lakefile            |  1 +
 src/llthread.c      |  3 ++-
 test/test_error.lua | 17 +++++++++++++++++
 5 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 test/test_error.lua

diff --git a/.travis.yml b/.travis.yml
index 19f6f5b..1f52bf6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -58,6 +58,7 @@ script:
   - lua test_threads_attr.lua
   - lua test_integer.lua
   - lua test_interrupt.lua
+  - lua test_error.lua
   # - lua test_register_llthreads.lua
 
 notifications:
diff --git a/appveyor.yml b/appveyor.yml
index 46a3235..b405930 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -73,6 +73,7 @@ test_script:
   - lua test_threads_attr.lua
   - lua test_integer.lua
   - lua test_interrupt.lua
+  - lua test_error.lua
   # - lua test_register_llthreads.lua
 
 after_test:
diff --git a/lakefile b/lakefile
index af9661e..a5cb006 100644
--- a/lakefile
+++ b/lakefile
@@ -45,6 +45,7 @@ target('test', install, function()
   run_test('test_threads_ex_opt_2.lua')
   run_test('test_threads_attr.lua')
   run_test('test_interrupt.lua')
+  run_test('test_error.lua')
 
 
   if not test_summary() then
diff --git a/src/llthread.c b/src/llthread.c
index 66efe7c..57f8dc3 100644
--- a/src/llthread.c
+++ b/src/llthread.c
@@ -135,7 +135,8 @@ void llthread_log(lua_State *L, const char *hdr, const char *msg){
   if(lua_isnil(L, -1)){
     lua_pop(L, 1);
     fputs(hdr,  stderr);
-    fputs(msg,  stderr);
+    if (msg) fputs(msg,  stderr);
+    else     fputs("(no error message)",  stderr);
     fputc('\n', stderr);
     fflush(stderr);
     return;
diff --git a/test/test_error.lua b/test/test_error.lua
new file mode 100644
index 0000000..1407ea8
--- /dev/null
+++ b/test/test_error.lua
@@ -0,0 +1,17 @@
+local llthreads = require"llthreads"
+local utils     = require "utils"
+
+local include = utils.thread_init .. [[
+local llthreads = require"llthreads"
+]]
+
+local thread = llthreads.new(include .. [[
+  error({})
+]])
+
+thread:start()
+local ok, err = thread:join()
+print(ok, err)
+assert(not ok)
+print("Done!")
+
-- 
cgit v1.2.3-55-g6feb