Aqua.jl finds many ambiguities in Core, Base

Tooling Package Management
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1

I’m using Aqua.jl on my package and have addressed all issues that Aqua complained about except that it finds many ambiguities when I call Aqua.test_all on my package, but none if I call Aqua.test_ambiguities on my package (the latter excludes Core and Base).

There are many messages like the one below. Can I ignore such ambiguities? If not, how can I address them?

55 ambiguities found
Ambiguity #1
ForwardDiff.Dual(args...) @ ForwardDiff ~/.julia/packages/ForwardDiff/PcZ48/src/dual.jl:73
(::Type{T})(x::Base.TwicePrecision) where T<:Number @ Base twiceprecision.jl:266

Possible fix, define
  ForwardDiff.Dual(::Base.TwicePrecision)
2

I haven’t tried recently, but I generally avoid running Aqua’s ambiguity test. Instead I just use Test.detect_ambiguities(MyPackage) and see if the resulting list is empty.

3

Any idea if the checks differ between Test and Aqua?

4

I think Aqua passes a long list of modules, some of which are “not yours.” I think this has some history: Test.detect_ambiguities originally (many Julia releases ago) didn’t do a good job with cross-package ambiguities, and so Aqua’s fix (at the cost of false positives) was to supply a superset of modules. But then I think what happened is that Test.detect_ambiguities got fixed, and now the Aqua approach is actively counterproductive. But I am not sure of any of this, as I wasn’t involved in the work. (CC @vtjnash.)

Aqua just calls detect_ambiguities so it’s presumably down to what gets passed in and how the results are processed.

5

FTR, there doesn’t seem to be any ambiguities in Julia itself, at least on nightly:

julia> using Test, LinearAlgebra

julia> detect_ambiguities(Main, Base, LinearAlgebra, recursive = true)
Skipping Base.HashArrayMappedTries.delete
Skipping Base.HashArrayMappedTries.insert
Tuple{Method, Method}[]

So these are bugs in user packages, ForwardDiff, in your example:

julia> using ForwardDiff

julia> detect_ambiguities(Main, Base, LinearAlgebra, ForwardDiff, recursive = true)
Skipping Base.HashArrayMappedTries.delete
Skipping Base.HashArrayMappedTries.insert
26-element Vector{Tuple{Method, Method}}:
[...]
6

Right, albeit that OTOH Aqua claims that by default it tests for ambiguities in the package itself, Core, and Base.