Different behavior when indexing with ColumnIndex vs Integers

[juliasloan25]

Describe the bug

When calling column on a SpectralElementSpace2D, we see different behavior when indexing with a ColumnIndex or with Integers.

With integers we get the expected behavior - a new PointSpace. With ColumnIndex however the fallback method is called which does nothing, and the input space is returned unchanged.

To Reproduce

import ClimaCore
import ClimaComms
import ClimaUtilities

FT = Float64
xlim = FT.((0, 1))
ylim = FT.((0, 1))
context = ClimaComms.context()

domain_x = ClimaCore.Domains.IntervalDomain(
    ClimaCore.Geometry.XPoint(xlim[1]),
    ClimaCore.Geometry.XPoint(xlim[2]),
    periodic = true,
)
domain_y = ClimaCore.Domains.IntervalDomain(
    ClimaCore.Geometry.YPoint(ylim[1]),
    ClimaCore.Geometry.YPoint(ylim[2]),
    periodic = true,
)
plane = ClimaCore.Domains.RectangleDomain(domain_x, domain_y)
mesh = ClimaCore.Meshes.RectilinearMesh(plane, 1, 1)
grid_topology = ClimaCore.Topologies.Topology2D(context, mesh)
quad = ClimaCore.Spaces.Quadratures.GL{1}()
space_2d = ClimaCore.Spaces.SpectralElementSpace2D(
    grid_topology,
    quad,
)

# Observe different behaviors when using ColumnIndex vs. Integers
ClimaCore.Spaces.column(space_2d, 1, 1, 1) isa ClimaCore.Spaces.PointSpace # true
ClimaCore.Spaces.column(space_2d, ClimaCore.Grids.ColumnIndex((1, 1), 1)) isa ClimaCore.Spaces.PointSpace # false
ClimaCore.Spaces.column(space_2d, ClimaCore.Grids.ColumnIndex((1, 1), 1)) == space_2d # true

Project

ClimaCore v0.14.35

System details

Any relevant system information:

• ClimaCore v0.14.35
• Julia version 1.11.5
• operating system MacOS Sequoia 15.5

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