In trying to run a design (a configurable switch block, basically) through the flow, I get this error:

[INFO] [PDNG-0013] Inserting stdcell grid - grid
-code 1 -level 0 -errorcode NONE -errorinfo {can't read "stripe_locs(met4,GROUND)": no such element in array
    while executing
"::odb::subtractSet $stripe_locs($layer_name,$tag) [dict get $blockages $layer_name]"
    (procedure "cut_blocked_areas" line 12)
    invoked from within
"cut_blocked_areas $tag"
    (procedure "add_grid" line 62)
...
...
[CRIT] [PDNG-9999] Unexpected error: can't read "stripe_locs(met4,GROUND)": no such element in array

Has anyone else gotten this / does anyone know what causes it? It appears to be while OpenROAD is routing power and ground on the upper metal layers, but I don't know much aside from that.

I had the same issue I believe, response I got was "Sounds like you're dealing with a small design. If that's the case, check this: https://github.com/efabless/openlane/wiki#how-to-add-a-small-design" I followed that and it fixed it

Thanks!