[Tarantool-patches] [PATCH v2 0/3] Merger's NULL defererence

[Alexander Turenko <alexander.turenko@tarantool.org>]

Differences from v1
-------------------

- Added the patch to don't leave garbage on a reusable Lua stack (2.5th
  patch in v1 series).
- Dropped the patch, which trims luaL_ prefix from next() and destroy()
  implementations (1st patch in v1 series).
- [minor] Drop redundant `struct tuple;` definition from a test.
- [minor] Make `luacheck -r` happy with gh-4954-merger-via-c.test.lua.
- [minor] Small wording and formatting fixes.

See the v1 series for more detailed description of changes and the
related discussions:

https://lists.tarantool.org/pipermail/tarantool-patches/2020-June/017325.html

Overview of the patchset
------------------------

The first patch just fixes NULL pointer dereference that occurs due to
the wrong assumption: I did think that fiber().storage.lua.stack is
always exists and non-NULL.

The second patch fix merge sources to don't leave any garbage on a
reusable Lua stack (it may matter if we'll use a merge source from C
code).

The third commit is the optimization: it allows to don't create a new
Lua state in merger when possible.

Changelog entry
---------------

@ChangeLog

- merger: fix NULL pointer dereference when merger is called via the
  binary protocol (say, via net.box) (gh-4954)

Links
-----

https://github.com/tarantool/tarantool/issues/4954
Totktonada/gh-4954-fix-merger-segfault-full-ci

----

Alexander Turenko (3):
  merger: fix NULL dereference when called via iproto
  merger: clean fiber-local Lua stack after next()
  lua: expose temporary Lua state for iproto calls

 src/box/lua/call.c                            |  27 ++
 src/box/lua/merger.c                          | 200 ++++++++++++--
 src/lib/core/fiber.h                          |  14 +-
 test/CMakeLists.txt                           |   1 +
 test/box-tap/CMakeLists.txt                   |   4 +
 test/box-tap/check_merge_source.c             | 108 ++++++++
 test/box-tap/gh-4954-merger-via-c.test.lua    | 251 ++++++++++++++++++
 .../gh-4954-merger-via-net-box.test.lua       | 129 +++++++++
 8 files changed, 708 insertions(+), 26 deletions(-)
 create mode 100644 test/box-tap/CMakeLists.txt
 create mode 100644 test/box-tap/check_merge_source.c
 create mode 100755 test/box-tap/gh-4954-merger-via-c.test.lua
 create mode 100755 test/box-tap/gh-4954-merger-via-net-box.test.lua

-- 
2.25.0