Scrip edge and node order changes each time the grid is loaded

[Sevans711]

Version

v2026.08.01

How did you install UXarray?

Source

What happened?

Loading a grid from a SCRIP source leads to a different order for nodes and edges each time the grid is loaded.

I noticed this while exploring MESACLIP data on casper, but I can also see that the bug occurs in the SCRIP example in uxarray.tutorial.

What did you expect to happen?

I expected the node and edge order to be based solely on the file, and be the same each time it is loaded, not to change in a seemingly-random way when the file is loaded multiple times.

Can you provide a MCVE to repoduce the bug?

gridA = ux.tutorial.open_grid('scrip-ne30pg2')
gridB = ux.tutorial.open_grid('scrip-ne30pg2')
gridA == gridB   # expected True, got False.
# Same bug if using 'scrip-outCSne8' instead.

# Also can see it by repeatedly running the following two lines in a jupyter cell:
arr = ux.tutorial.open_grid('scrip-ne30pg2')['RELHUM']
arr.isel(lev=0, n_node=slice(None, 100)).plot()
# The plot will change each time, because the node order has changed.
# Similar issue if using n_edge=slice(None, 100).

# If using n_face=slice(None, 100), the plot does not change
# (faces' locations and data remain correct).

# If not slicing at all, the plot does not change,
# because arr.plot() is not sensitive to node/edge order.