recommend explicit `using Foo: Foo, ...` in package code (was: "using considered harmful") (#42080)
I feel we are heading up against a "`using` crisis" where any new
feature that is implemented by exporting a new name (either in Base or a
package) becomes a breaking change. This is already happening
(https://github.com/JuliaGPU/CUDA.jl/pull/1097,
https://github.com/JuliaWeb/HTTP.jl/pull/745) and as projects get bigger
and more names are exported, the likelihood of this rapidly increases.
The flaw in `using Foo` is fundamental in that you cannot lexically see
where a name comes from so when two packages export the same name, you
are screwed. Any code that relies on `using Foo` and then using an
exported name from `Foo` is vulnerable to another dependency exporting
the same name.
Therefore, I think we should start to strongly discourage the use of
`using Foo` and only recommend `using Foo` for ephemeral work (e.g. REPL
work).
---------
Co-authored-by: Dilum Aluthge <dilum@aluthge.com>
Co-authored-by: Mason Protter <mason.protter@icloud.com>
Co-authored-by: Max Horn <max@quendi.de>
Co-authored-by: Matt Bauman <mbauman@juliahub.com>
Co-authored-by: Alex Arslan <ararslan@comcast.net>
Co-authored-by: Ian Butterworth <i.r.butterworth@gmail.com>
Co-authored-by: Neven Sajko <s@purelymail.com>
julia
ee09ae70 - recommend explicit `using Foo: Foo, ...` in package code (was: "using considered harmful") (#42080)
