Explicit imports

[GunnarFarneback]

• Stop doing implicit imports and be explicit about all imports. Thanks to @ericphanson for ExplicitImports.jl.
• Make regression tests of compat files ignore whitespace around hyphens. Fixes Bad test now errors #99.
• Remove dependency on AutoHashEquals. This was only used for a roundtrip test of the RegistryData struct and had no reasonable utility externally. Closes [compat] Update compat for AutoHashEquals #95.
• (Added) Check in the tests that imports remain explicit.

[DilumAluthge]

Could we also run ExplicitImports.jl as part of the test suite here, to make sure this doesn't regress?

[GunnarFarneback]

Maybe? ExplicitImports gives a note about Pkg.Types.semver_spec actually being owned by Pkg.Versions.semver_spec, but that is only true for sufficiently new Julia versions.

[DilumAluthge]

Would ExplicitImports be satisfied by:

@static if VERSION >= v"1.9-" # or whatever the correct version is
    const semver_spec = Pkg.Versions.semver_spec
else
    const semver_spec = Pkg.Types.semver_spec
end

[GunnarFarneback]

It's not really worth being that pedantic in the code. But when I checked the ExplicitImports README, the regression checking functions are quite specific about what things they look for.

[DilumAluthge]

@ericphanson What are your thoughts here? Could we run ExplicitImports in the test suite, but just tell ExplicitImports to skip semver_spec?

I would also be fine with doing the @static if..., even though it is a little annoying.

[GunnarFarneback]

A bigger problem is that ExplicitImports doesn't work with as old Julia versions as RegistryTools does.

[DilumAluthge]

We could omit ExplicitImports from the list of test-deps, and then in the test suite, if the Julia version is new enough, we could do Pkg.add(name = "ExplicitImports", uuid = "...", preserve=Pkg.PRESERVE_ALL).

[GunnarFarneback]

It ain't pretty, but yes, it works.

[ericphanson]

The regression testing functions have an ignore kwarg to skip stuff like this btw! Also skip for whole modules.

[ericphanson]

it would be nice to drop this... also to get ExplicitImports into Aqua.. at some point I will see about expanding compat