From Wikipedia:
"An anti-pattern is a common response to a recurring problem that is usually ineffective and risks being highly counterproductive."
The developers of OpenBMC do not get 100% of decisions right 100% of the time. That, combined with the fact that software development is often an exercise in copying and pasting, results in mistakes happening over and over again.
This page aims to document some of the anti-patterns that exist in OpenBMC to ease the job of those reviewing code. If an anti-pattern is spotted, rather that repeating the same explanations over and over, a link to this document can be provided.
(1 paragraph) Describe how to spot the anti-pattern.
(1 paragraph) Describe the negative effects of the anti-pattern.
(1 paragraph) Describe why the anti-pattern exists. If you don't know, try running git blame and look at who wrote the code originally, and ask them on the mailing list or in IRC what their original intent was, so it can be documented here (and you may possibly discover it isn't as much of an anti-pattern as you thought). If you are unable to determine why the anti-pattern exists, put: "Unknown" here.
(1 paragraph) Describe the preferred way to solve the problem solved by the anti-pattern and the positive effects of solving it in the manner described.
RDEPENDS_${PN} = "libsystemd"
Out of the box bitbake examines built applications, automatically adds runtime dependencies and thus ensures any library packages dependencies are automatically added to images, sdks, etc. There is no need to list them explicitly in a recipe.
Dependencies change over time, and listing them explicitly is likely prone to errors - the net effect being unnecessary shared library packages being installed into images.
Consult https://www.yoctoproject.org/docs/latest/mega-manual/mega-manual.html#var-RDEPENDS for information on when to use explicit runtime dependencies.
The initial bitbake metadata author for OpenBMC was not aware that bitbake added these dependencies automatically. Initial bitbake metadata therefore listed shared library dependencies explicitly, and was subsequently copy pasted.
Do not list shared library packages in RDEPENDS. This eliminates the possibility of installing unnecessary shared library packages due to unmaintained library dependency lists in bitbake metadata.