[#MDEV-26567] Attempt to remove non-existing mariadb-libs causes removal of entire MariaDB installation

RHEL 7 and CentOS 7 have a package called mariadb-libs in the default installation:

mariadb-libs-5.5.56-2.el7.x86_64

It used to cause troubles for our installation, so our packaging is now aware of it in the form of (at least)

  IF(RPM MATCHES "(rhel|centos)[67]")

    SET(CPACK_RPM_common_PACKAGE_REQUIRES "MariaDB-compat")

    SET(CPACK_RPM_compat_PACKAGE_CONFLICTS "mariadb-libs < 1:10.1.0")

  ENDIF()

However, it causes a weird effect, which is probably unexpected and likely undesired.

Let's say I remove the package first, before installing any MariaDB packages. It removes easily and only pulls postfix along:

[buildbot@centos74-amd64 ~]$ rpm -qa | grep mariadb-libs

mariadb-libs-5.5.56-2.el7.x86_64

[buildbot@centos74-amd64 ~]$ sudo yum remove -y mariadb-libs

Loaded plugins: fastestmirror

Resolving Dependencies

--> Running transaction check

---> Package mariadb-libs.x86_64 1:5.5.56-2.el7 will be erased

--> Processing Dependency: libmysqlclient.so.18()(64bit) for package: 2:postfix-2.10.1-6.el7.x86_64

--> Processing Dependency: libmysqlclient.so.18(libmysqlclient_18)(64bit) for package: 2:postfix-2.10.1-6.el7.x86_64

--> Running transaction check

---> Package postfix.x86_64 2:2.10.1-6.el7 will be erased

--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================================================================================================================================================================================

 Package                                                    Arch                                                 Version                                                       Repository                                               Size

=============================================================================================================================================================================================================================================

Removing:

 mariadb-libs                                               x86_64                                               1:5.5.56-2.el7                                                @anaconda                                               4.4 M

Removing for dependencies:

 postfix                                                    x86_64                                               2:2.10.1-6.el7                                                @anaconda                                                12 M

Transaction Summary

=============================================================================================================================================================================================================================================

Remove  1 Package (+1 Dependent package)

Installed size: 17 M

Downloading packages:

Running transaction check

Running transaction test

Transaction test succeeded

Running transaction

  Erasing    : 2:postfix-2.10.1-6.el7.x86_64                                                                                                                                                                                             1/2

  Erasing    : 1:mariadb-libs-5.5.56-2.el7.x86_64                                                                                                                                                                                        2/2

  Verifying  : 1:mariadb-libs-5.5.56-2.el7.x86_64                                                                                                                                                                                        1/2

  Verifying  : 2:postfix-2.10.1-6.el7.x86_64                                                                                                                                                                                             2/2

Removed:

  mariadb-libs.x86_64 1:5.5.56-2.el7

Dependency Removed:

  postfix.x86_64 2:2.10.1-6.el7

Complete!

Then I install a bunch of MariaDB packages, they install all right.
There is still no mariadb-libs of course.
But if I try to remove it, instead yum removes our MariaDB-compat, which in turns pulls together the whole installed set:

[buildbot@centos74-amd64 ~]$ rpm -qa | grep mariadb-libs

[buildbot@centos74-amd64 ~]$ sudo yum remove -y mariadb-libs

Loaded plugins: fastestmirror

Resolving Dependencies

--> Running transaction check

---> Package MariaDB-compat.x86_64 0:10.5.12-1.el7.centos will be erased

--> Processing Dependency: MariaDB-compat for package: MariaDB-common-10.5.12-1.el7.centos.x86_64

--> Running transaction check

---> Package MariaDB-common.x86_64 0:10.5.12-1.el7.centos will be erased

--> Processing Dependency: MariaDB-common for package: MariaDB-shared-10.5.12-1.el7.centos.x86_64

--> Processing Dependency: MariaDB-common for package: MariaDB-server-10.5.12-1.el7.centos.x86_64

--> Processing Dependency: MariaDB-common for package: MariaDB-client-10.5.12-1.el7.centos.x86_64

--> Processing Dependency: MariaDB-common for package: MariaDB-devel-10.5.12-1.el7.centos.x86_64

--> Processing Dependency: MariaDB-common for package: MariaDB-backup-10.5.12-1.el7.centos.x86_64

...

I only checked 10.5 and 10.6, but the packaging logic looks the same everywhere.

[MDEV-26567] Attempt to remove non-existing mariadb-libs causes removal of entire MariaDB installation Created: 2021-09-07 Updated: 2023-04-27
Status:	Open
Project:	MariaDB Server
Component/s:	Platform RedHat
Affects Version/s:	10.2, 10.3, 10.4, 10.5, 10.6
Fix Version/s:	10.4, 10.5, 10.6

[MDEV-26567] Attempt to remove non-existing mariadb-libs causes removal of entire MariaDB installation Created: 2021-09-07 Updated: 2023-04-27