Bug: CompileError lib/useful.ex:24: Plug.Upload.__struct__/0 is undefined 🔥

[nelsonic]

As noted by @LuchoTurtle in dwyl/mvp#406 and now confirmed in our other projects that use the Useful package: https://github.com/dwyl/gogs/actions/runs/5863993387/job/15898337199#step:8:51

== Compilation error in file lib/useful.ex ==
Error: ** (CompileError) lib/useful.ex:24: Plug.Upload.__struct__/0 is undefined, 
cannot expand struct Plug.Upload. Make sure the struct name is correct. 
If the struct name exists and is correct but it still cannot be found, 
you likely have cyclic module usage in your code
could not compile dependency :useful, "mix compile" failed. 
Errors may have been logged above. 
You can recompile this dependency with "mix deps.compile useful", 
update it with "mix deps.update useful" 
or clean it with "mix deps.clean useful"
    expanding struct: Plug.Upload.__struct__/0
    lib/useful.ex:24: Useful.atomize_map_keys/1

We either need to add Plug as dependency, not just :dev and :test the way it is now:
https://github.com/dwyl/useful/blame/35278cfb0c697cab555becfcc27ccf46731e61ee/mix.exs#L47-L48

OR we need to define our own "dummy" Struct.
But since the Useful package is used in at least one Elixir project that isn't a Phoenix App,
I think we won't have any other choice but to make Plug a dependency. 💭
Let's see how we can do this efficiently. 👌

[nelsonic]

I thought a good starting point for trying to understand this is to search for Plug.Upload in our imgup project that uses this struct: https://github.com/search?q=repo%3Adwyl%2Fimgup%20Plug.Upload&type=code

But sadly it was not insightful. 💭

[nelsonic]

The version of Plug being used by Phoenix at the time of writing is 1.14:
https://github.com/phoenixframework/phoenix/blob/e095f23ff62efb2f8c1205b0cc67bfacd80b11ed/mix.exs#L73

So I'm replacing:

useful/mix.exs

Line 48 in 35278cf

{:plug, "~> 1.10", only: [:dev, :test]}

with:

{:plug, "~> 1.14"}

And will alias the Plug.Upload Struct in the useful.ex file.

[nelsonic]

Aliasing the Plug.Upload Struct does not appear to be used:

Going to remove it. ✂️

[nelsonic]

Patch Package published to https://hex.pm/packages/useful/1.12.1 📦
Tested in: dwyl/gogs#75 ✅
No longer has compilation error.

PR: #53

[LuchoTurtle]

Closing, as #53 was merged.