Why does yum install work, but yum search and yum info not?

Question

I'm running the following commands on CentOs 8

$ cat /etc/redhat-release 
CentOS Linux release 8.2.2004 (Core) 

I start off with a clean and updated yum database:

$ yum clean all
46 files removed

$ yum update
CentOS-8 - AppStream                                                                                                                                                                                           18 MB/s | 5.8 MB     00:00    
CentOS-8 - Base                                                                                                                                                                                                15 MB/s | 2.2 MB     00:00    
CentOS-8 - Extras                                                                                                                                                                                             121 kB/s | 7.9 kB     00:00    
CentOS-8 - PowerTools                                                                                                                                                                                         9.0 MB/s | 1.9 MB     00:00    
Extra Packages for Enterprise Linux Modular 8 - x86_64                                                                                                                                                        271 kB/s | 117 kB     00:00    
Extra Packages for Enterprise Linux 8 - x86_64                                                                                                                                                                 26 MB/s | 8.0 MB     00:00    
yum Dependencies resolved.
Nothing to do.
Complete!

If I search for the cmake3 package with yum, or attempt to show details, it does not work:

$ yum search cmake3
Last metadata expiration check: 0:01:03 ago on Fri 11 Sep 2020 07:47:47 AM UTC.
No matches found.

$ yum info cmake3
Last metadata expiration check: 0:02:24 ago on Fri 11 Sep 2020 07:47:47 AM UTC.
Error: No matching Packages to list

If I attempt to install the cmake3 package, it installs the cmake package

$ yum install cmake3
Last metadata expiration check: 0:22:10 ago on Fri 11 Sep 2020 07:47:47 AM UTC.
Dependencies resolved.
==============================================================================================================================================================================================================================================
 Package                                                       Architecture                                        Version                                                       Repository                                              Size
==============================================================================================================================================================================================================================================
Installing:
 cmake                                                         x86_64                                              3.11.4-7.el8                                                  AppStream                                              8.1 M
Installing dependencies:
 cmake-data                                                    noarch                                              3.11.4-7.el8                                                  AppStream                                              1.3 M
 cmake-filesystem                                              x86_64                                              3.11.4-7.el8                                                  AppStream                                               40 k
 cmake-rpm-macros                                              noarch                                              3.11.4-7.el8                                                  AppStream                                               39 k
 libuv                                                         x86_64                                              1:1.23.1-1.el8                                                AppStream                                              134 k

Transaction Summary
==============================================================================================================================================================================================================================================
Install  5 Packages

Total download size: 9.7 M
Installed size: 29 M
Is this ok [y/N]: 

What is happening here? Why does search and info fail, but install succeed (and install a slightly differently pacakge)?

Answer 1

Since cmake3 is provided by the cmake package, that package will be installed by yum install, since no package with the exact cmake3 name exists:

# yum provides cmake3
cmake-3.11.4-7.el8.x86_64 : Cross-platform make system
Repo        : AppStream
Matched from:
Provide    : cmake3 = 3.11.4-7.el8

A similar example is in the yum manpage (which in RHEL8 redirects to dnf):

dnf install vim

DNF will automatically recognize that vim is not a package name, but will look up and install a package that provides vim with all the required dependencies. Note: Package name match has precedence over package provides match.