Package choices when installing web server

Question

While installing a web server, I've been pondering some serious question...
"Do I really need that package?"

I've noticed that when you install your packages for your web server,
you often have two "version" of the same package.

For example, while installing php7.4, you can install php-mbstring and php7.4-mbstring
Or php-gd and php7.4-gd.

So my question is, if I install php7.4-mbstring, do I also need to install php-mbstring?
Does it works the same with all packages having the same naming pattern (php-dev=>php7.4-dev, etc)

Answer 1

Typically, the package without the version number will "point" to the most current package via dependencies.

So today, you can install php-mbstring, and it will install php7.4-mbstring as well. Some time in the future, php7.5-mbstring will come out, and php-mbstring will then "point" to php7.5-mstring.

So if you have installed php-mbstring, it will resolve to a newer version next time dependencies are checked.

If you only have installed php7.4-mstring, you won't get the newer package.

Answer 2

The Guidelines for Naming Fedora Packages defines package names and deals with such cases as in your example. This convention is followed by almost all Linux distributions.

Multiple packages with the same base name

For many reasons, it is sometimes advantageous to keep multiple versions of a package in Fedora to be installed simultaneously. When doing so, the package name MUST reflect this fact. One package SHOULD use the base name (with no version information). All other packages derived from it MUST include the base name suffixed by either:

• The package version, which SHOULD include the periods present in the original version.
  • If the base package name ends with a digit, a single underscore ("_") MUST be appended to the name, and the version MUST be appended to that, in order to avoid confusion over where the name ends and the version begins.
  • If the base package name does not end with a digit, the version MUST be directly appended to the package name with no intervening separator.
• a hyphen ("-") followed by a descriptive suffix such as "stable" which provides some indication as to the nature of the packaged version.

Examples:

• The python-sqlalchemy package occasionally has multiple versions in Fedora for backwards compatibility. The most current version of python-sqlalchemy is named python-sqlalchemy and an older supported version is python-sqlalchemy0.5. No delimiter is used in this situation.
• The most current version of the v8 package is named v8. In order to package version "3.13", the package MUST be named v8_3.13.

So the version with just the name is the base version, all packages that append more information are derived versions.

Many types of derivation are possible. One of the most common one is used for marking older versions that are kept for compatibility with older software. But others are possible, such as additional tools or libraries for different programming languages.