> Another common theme is that while Julia is great at composition, it's not clear what's expected to work and what isn't, because the interfaces are informal and not checked.

This is THE huge issue when combined with the other variables:

- you often have hundreds of depedencies that interlock

- you often have dependencies that work with multiple packages, and they will often pull them all into your tree (there are sometimes "bridge packages" written, but that is O(n^2) in the number of packages)

- many maintainers do not care about good versioning practices, because they are not enforced, and it is not their problem when they break a bajillion other packages

- many people writing Julia code are not software developers. this is great! but they usually don't look at what their testing coverage looks like. often the CI always fails on a package and it's ignored.

Would Julia only allow multiple dispatch as a link between those packages, the situation would look a little better. But often the packages also talk through simple accesses of values like `X.someproperty`. I've seen situations where maintainers would add and remove these properties and break their own other libraries. Better "enforcement" of these types of things - however that would look like - would be a huge improvement for the time sink that is maintaining a Julia package.