Conditionally overload Krylov.ktypeof

Author: charleskawczynski

Project.toml

@@ -21,6 +21,7 @@ IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 PkgVersion = "eebad327-c553-4316-9ea0-9fa01ccd7688"
 RecursiveArrayTools = "731186ca-8d62-57ce-b412-fbd966d074cd"
+Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 RootSolvers = "7181ea78-2dcb-4de3-ab41-2b8ab5a31e74"
 Rotations = "6038ab10-8711-5258-84ad-4b1120ba62dc"
 SparseArrays = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"

src/ClimaCore.jl

@@ -18,6 +18,14 @@ include("Hypsography/Hypsography.jl")
 include("Limiters/Limiters.jl")
 include("InputOutput/InputOutput.jl")
 
+using Requires
+function __init__()
+    @require Krylov = "ba0b0d4f-ebba-5204-a429-3ac8c609bfb7" include(
+        joinpath("weak_deps", "Krylov.jl"),
+    )
+    return nothing
+end
+
 include("deprecated.jl")
 
 end # module

src/weak_deps/Krylov.jl

@@ -0,0 +1,16 @@
+#=
+`Krylov.ktypeof` is defined here, if `Krylov`
+is loaded to avoid the need for type piracy.
+
+```julia
+using Krylov # to load this file
+using ClimaCore
+```
+
+TODO: Use package extensions when we upgrade to Julia 1.9.
+=#
+
+import ClimaComms
+import .Krylov
+Krylov.ktypeof(x::Fields.FieldVector) =
+    ClimaComms.array_type(x){eltype(parent(x)), 1}