Some open-source projects make combined releases where the version number of each package(library) is increased to the same version.
Examples in Java are:
- org.springframework
- com.fasterxml.jackson
- org.hamcrest
This implies that some packages may get a new version even though they have not changed (nor their dependencies). I don't think this violates semantic versioning.
Benefits I see is that:
- Users can use a single version to monitor and upgrade
- All users likely to use the same combination of libraries
Drawbacks:
- Users using just one out of many libraries might be notified about an "update" though the package to download has not changed
- If many users use just a sub-package, then all bug reports for one version are equally for a range of versions, which is difficult to track. Reverting to the previous "different" version to avoid a bug becomes more complex.