[Tarantool-patches] [PATCH luajit 1/2] Fix corner case of os.time().

[Evgeniy Temirgaleev via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

From: Mike Pall <mike>

Thanks to Temir Galeev. #1470

(cherry picked from commit 72d2061ae2fa9a5fd45237943f9982baf59435ec)

This patch fixes invalid os.time(t) behavior, when it handles -1 time value
as a fail of the libc mktime() regardless of the errno value.

Temir Galeev:
* added the description and the test for the patch

Part of tarantool/tarantool#12480
---
 src/lib_os.c                                         |  3 ++-
 .../lj-1470-os-time-epoch-minus-1s.test.lua          | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 test/tarantool-tests/lj-1470-os-time-epoch-minus-1s.test.lua

diff --git a/src/lib_os.c b/src/lib_os.c
index ffbc3fdc..f6841357 100644
--- a/src/lib_os.c
+++ b/src/lib_os.c
@@ -242,9 +242,10 @@ LJLIB_CF(os_time)
     ts.tm_mon = getfield(L, "month", -1) - 1;
     ts.tm_year = getfield(L, "year", -1) - 1900;
     ts.tm_isdst = getboolfield(L, "isdst");
+    errno = 0;
     t = mktime(&ts);
   }
-  if (t == (time_t)(-1))
+  if (t == (time_t)(-1) && errno != 0)
     lua_pushnil(L);
   else
     lua_pushnumber(L, (lua_Number)t);
diff --git a/test/tarantool-tests/lj-1470-os-time-epoch-minus-1s.test.lua b/test/tarantool-tests/lj-1470-os-time-epoch-minus-1s.test.lua
new file mode 100644
index 00000000..6b5703e4
--- /dev/null
+++ b/test/tarantool-tests/lj-1470-os-time-epoch-minus-1s.test.lua
@@ -0,0 +1,12 @@
+local tap = require('tap')
+
+-- The test file demonstrates os.time() fail to return -1 time value.
+-- See also: https://github.com/LuaJIT/LuaJIT/issues/1470.
+local test = tap.test('lj-1470-os-time-epoch-minus-1s')
+
+test:plan(1)
+
+local minus_1s_time = os.date("*t", -1)
+test:is(os.time(minus_1s_time), -1, 'correct os.time()')
+
+test:done(true)
-- 
2.49.0