Remove performance-/precompilation-time harmful @eval

[simone-silvestri]

this PR fixes the issue of having @eval inside callable functions not resolved at compile time

closes #3555

cc @vchuravy

[vchuravy]

Now I am questioning the use of eval from the beginning :)

You were defining new global variables.

[glwagner]

what was the purpose of the @eval?

[vchuravy]

The next one I ran into is

Oceananigans.jl/src/Advection/reconstruction_coefficients.jl

Line 215 in 00f028b

if grid isa Nothing

So one alternative is to use named tuples instead of variables.

@inline function compute_reconstruction_coefficients(grid, FT, scheme; order)

    method = scheme == :Centered ? 1 : scheme == :Upwind ? 2 : 3

    rect_metrics = (:xᶠᵃᵃ, :xᶜᵃᵃ, :yᵃᶠᵃ, :yᵃᶜᵃ, :zᵃᵃᶠ, :zᵃᵃᶜ)

    if grid isa Nothing
        coeffs = (; (m => nothing for m in rect_metrics)...)
    else
        metrics = coordinates(grid)
        dirsize = (:Nx, :Nx, :Ny, :Ny, :Nz, :Nz)

        arch       = architecture(grid)
        Hx, Hy, Hz = halo_size(grid)
        new_grid   = with_halo((Hx+1, Hy+1, Hz+1), grid)
        coeffs = (; (rect_metric => calc_reconstruction_coefficients(
                FT, getfield(new_grid, metric), arch, getfield(new_grid, dir), Val(method); order = order)
            for (dir, metric, rect_metric) in zip(dirsize, metrics, rect_metrics))...)
    end

    return tuple(coeffs...) # actually return named tuple to be order invariant
end

[glwagner]

Suggested change

	coeff_xᶠᵃᵃ = calc_reconstruction_coefficients(FT, getproperty(metrics[1], new_grid), arch, new_grid.Nx, Val(method); order)
	coeff_xᶠᵃᵃ = reconstruction_coefficients(FT, getproperty(metrics[1], new_grid), arch, new_grid.Nx, Val(method); order)

[glwagner]

nice to clean up the names while we are at it

[vchuravy]

I think we need to look at all eval usage

I hit:

function minimum_spacing(dir, grid, ℓx, ℓy, ℓz)
    spacing = eval(Symbol(dir, :spacing))
    LX, LY, LZ = map(destantiate, (ℓx, ℓy, ℓz))
    Δ = KernelFunctionOperation{LX, LY, LZ}(spacing, grid, ℓx, ℓy, ℓz)

    return minimum(Δ)
end

next. Which probably should be getglobal?

[glwagner]

@simone-silvestri are you going to shepherd this through to completion?

[simone-silvestri]

I couldn't find any other @eval inside functions so I think we are clear.
@vchuravy can you confirm?