[Tarantool-patches] [PATCH 0/2] Update CMake minimal version in Tarantool

[Igor Munkin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

This series contains auxiliary activities required for this issue[1].

The second and main patch updates Tarantool build infrastructure to use
CMake 3.1 or newer. Since this CMake release[2] the vital for LuaJIT
testing environment feature is introduced: one can use generator
expressions[3] in target DEPENDS section. This CMake feature is used to
pass either Tarantool binary or LuaJIT binary to the newly implemented
testing machinery with no changes in it.

Unfortunately, not all distributions provides CMake 3.1 or newer from their
repositories. Here is the actual list of default packages providing CMake
for the distributions that support Tarantool:
| Distro             | CMake version | Repo                |
|--------------------+---------------+---------------------|
| CentOS 6           | 2.8.12        | base                |
| CentOS 7           | 2.8.12        | base                |
| CentOS 8           | 3.11.4        | appstream           |
| Debian Jessie      | 3.0.2         | jessie/main         |
| Debian Stretch     | 3.7.2         | stretch/main        |
| Debian Buster      | 3.13.4        | buster/main         |
| Fedora 28          | 3.14.4        | updates             |
| Fedora 29          | 3.14.5        | updates             |
| Fedora 30          | 3.17.2        | updates             |
| Fedora 31          | 3.17.4        | updates             |
| Fedora 32          | 3.17.4        | updates             |
| FreeBSD 12         | 3.15.5        | default             |
| OSX 14             | 3.19.3        | brew                |
| OSX 15             | 3.19.3        | brew                |
| Ubuntu 14.04       | 2.8.12        | trusty/main         |
| Ubuntu 16.04       | 3.5.1         | xenial-updates/main |
| Ubuntu 18.04       | 3.10.2        | bionic-updates/main |
| Ubuntu 20.04       | 3.16.3        | focal/main          |
| openSUSE Leap 15.1 | 3.10.2        | Main                |
| openSUSE Leap 15.2 | 3.17.0        | Main                |

As one can see, there are no required packages provided by default for
the following old distributions: CentOS 6, CentOS 7, Debian Jessie and
Ubuntu 14.04. There are alternative packages (i.e. cmake3) providing a
newer CMake than the default one for the old packages:
| Distro             | CMake3 version  | Repo                    |
|--------------------+-----------------+-------------------------|
| CentOS 6           | 3.6.1           | epel*                   |
| CentOS 7           | 3.17.5          | epel*                   |
| Ubuntu 14.04       | 3.5.1           | trusty-updates/universe |

(*) Unfortunately, I failed to find the way to make rpmbuild install and
    enable EPEL repository prior to the build step. However, cmake3
    requirement obligues user to enable EPEL by himself, otherwise this
    dependency is left unmet. If there are any issues with building an
    RPM on CentOS 7 please proceed to the docs:
    https://www.tarantool.io/en/doc/latest/dev_guide/building_from_source/

So the last problem is Debian Jessie: the required CMake toolchain is
provided neither via the default repository nor via the auxiliary one
(e.g. updates like it's done for Ubuntu 14.04). Anyway, Debian Jessie
long term support has reached its EOL[4], so we can freely drop this
distribution from our regular building testing. This is done in the
first patch of this series.

NB: Be careful with updating CMake to 3.1 in CMakeLists. The following
patch breaks Tarantool build.
| diff --git a/CMakeLists.txt b/CMakeLists.txt
| index 4fbd19558..6dc78fa88 100644
| --- a/CMakeLists.txt
| +++ b/CMakeLists.txt
| @@ -1,4 +1,4 @@
| -cmake_minimum_required(VERSION 2.8)
| +cmake_minimum_required(VERSION 3.1)
|  
|  project(tarantool C CXX)
|  

Surprisingly, as a result of this change -Wno-gnu-alignof-expression
flag is removed from CFLAGS and the build fails on OSX with the
following error[5]:
| /tarantool/src/box/field_map.c:69:36: error: '_Alignof' applied to an expression is a GNU extension [-Werror,-Wgnu-alignof-expression]
|                 region_aligned_alloc(region, sz, alignof(*extent));
|                                                  ^
| /Library/Developer/CommandLineTools/usr/lib/clang/12.0.0/include/stdalign.h:15:17: note: expanded from macro 'alignof'
| #define alignof _Alignof
|                 ^
| 1 error generated.

Anyway, I believe this is out of the scope of this series, so I just
leave this for the further CMake upgrade endeavors.

[1]: https://github.com/tarantool/tarantool/issues/4862
[2]: https://cmake.org/cmake/help/latest/release/3.1.html#commands
[3]: https://cmake.org/cmake/help/v3.1/manual/cmake-generator-expressions.7.html
[4]: https://www.debian.org/News/2020/20200709
[5]: https://gitlab.com/tarantool/tarantool/-/pipelines/243423841

Branch: https://github.com/tarantool/tarantool/tree/imun/cmake3-toolchain
Issue: https://github.com/tarantool/tarantool/issues/4862
CI is green: https://gitlab.com/tarantool/tarantool/-/pipelines/244503943

Igor Munkin (2):
  gitlab-ci: purge Debian Jessie from CI
  build: update minimal CMake version to 3.1

 .gitlab-ci.yml     | 12 ------------
 debian/control     |  9 ++++++++-
 rpm/tarantool.spec | 33 ++++++++++++++++++++++++++++++---
 3 files changed, 38 insertions(+), 16 deletions(-)

-- 
2.25.0