[tarantool-patches] [PATCH v2] lua/fiber: Fix abort on malformed join input

[Cyrill Gorcunov <gorcunov@gmail.com>]

If I create a new fiber and the join to himself we get an abort:

 | tarantool> f = require('fiber')
 | ---
 | ...
 |
 | tarantool> f.join(f.self())
 | tarantool: src/fiber.c:407: fiber_join: Assertion `fiber->flags & FIBER_IS_JOINABLE' failed.
 | Aborted (core dumped)

we should better throw an error.

v2: by georgy@
 - add a testcase

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
 src/lua/fiber.c         |    6 +++++-
 test/app/fiber.result   |   11 +++++++++++
 test/app/fiber.test.lua |    7 +++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

Index: tarantool.git/src/lua/fiber.c
===================================================================
--- tarantool.git.orig/src/lua/fiber.c
+++ tarantool.git/src/lua/fiber.c
@@ -676,10 +676,14 @@ lbox_fiber_join(struct lua_State *L)
 {
 	struct fiber *fiber = lbox_checkfiber(L, 1);
 	struct lua_State *child_L = fiber->storage.lua.stack;
-	fiber_join(fiber);
 	struct error *e = NULL;
 	int num_ret = 0;
 	int coro_ref = 0;
+
+	if (!(fiber->flags & FIBER_IS_JOINABLE))
+		luaL_error(L, "the fiber is not joinable");
+	fiber_join(fiber);
+
 	if (child_L != NULL) {
 		coro_ref = lua_tointeger(child_L, -1);
 		lua_pop(child_L, 1);
Index: tarantool.git/test/app/fiber.result
===================================================================
--- tarantool.git.orig/test/app/fiber.result
+++ tarantool.git/test/app/fiber.result
@@ -1454,6 +1454,17 @@ ch1:put(1)
 while f:status() ~= 'dead' do fiber.sleep(0.01) end
 ---
 ...
+--
+-- Test if fiber join() does not crash
+-- if unjoinable
+--
+fj = require('fiber')
+---
+...
+fj.join(fj.self())
+---
+- error: the fiber is not joinable
+...
 -- cleanup
 test_run:cmd("clear filter")
 ---
Index: tarantool.git/test/app/fiber.test.lua
===================================================================
--- tarantool.git.orig/test/app/fiber.test.lua
+++ tarantool.git/test/app/fiber.test.lua
@@ -623,6 +623,13 @@ ch1:put(1)
 
 while f:status() ~= 'dead' do fiber.sleep(0.01) end
 
+--
+-- Test if fiber join() does not crash
+-- if unjoinable
+--
+fj = require('fiber')
+fj.join(fj.self())
+
 -- cleanup
 test_run:cmd("clear filter")