[bitwizeshift]

Aside from what some other users have said, logging is fundamentally an observable side-effect of your library. It’s now a behavior that can become load-bearing — and putting it in library code forces this exposed behavior on the consumer.

As a developer, this gets frustrating. I want to present a clean and coherent output to my callers, and poorly-authored libraries ruin that — especially if they offer no mechanism to disable it.

It’s also just _sloppy_ in many cases. Well-designed library code often shouldn’t even need to log in the first place because it should clearly articulate each units side-effects; the composition of which should become clear to understand. Sadly, “design” has become a lost art in modern software development.

[ivan_gammel]

In Java world logging in libraries is effectively a no-op unless explicitly enabled by user, so side effects are negligible. And it actually does make sense, e.g. when a library is offering a convenient abstraction level over i/o, parsing or other stuff with initially unknown failure modes, where some logs may help clarifying the picture beyond handling an exception or error code. The way logging is done there is the art of good software design, which has never been lost (it may have not reached other platforms though). So I disagree with you and some other commenters: strict Verbot is dogmatic, and good design is never dogmatic.