fix(Nigeria): correct the assets KNOWN OPEN DEFECT note — its edit 1 is inert

[ligon]

A tracked file currently prescribes a fix that provably cannot work. Comment-only correction.

What was wrong

Nigeria/_/data_scheme.yml’s KNOWN OPEN DEFECT note (merged via #625) prescribes two edits. Its diagnosis is correct and is kept verbatim — wave 2 is a per-unit roster, item_seq is exactly the level the canonical (t,i,j) grain drops, and first() destroys ₦147,297,485 (25.6%) in each quarter.

Edit 1 — index_info assets -> (t,i,j,item_seq) — is INERT for Nigeria.

Verified by experiment (PR #629, 2026-07-22): item_seq was declared in 2012-13’s idxvars and final_index, the wave rebuilt cold, and the frame comes back on index [i,t,j] regardless — identical rows, identical Value. The dfs: merge in Wave.grab_data drops the level before final_index applies. That is GH #323 Site 4 (PR #627), not Site 1. Nigeria cannot emit item_seq at all today.

And it is worse than inert: making it canonical would leave edit 2 as dead code and silently disable the GH #498 guard for all 25 assets countries, none of which carry the level either.

What is right

Edit 2 — _ADDITIVE_MEASURE_COLUMNS[assets] = (Value,) — is correct, and is implemented in #629.

The note now also records a trap found while implementing it, because it generalises to any future registration:

Adding a table to _ADDITIVE_MEASURE_COLUMNS also silences its grain audit wholesale.

Harmless while food_acquired was the sole entry — its collapse reconciles every column it carries. But assets carries Age, which no reducer reconciles at (t,i,j), so the naive registration turned a loud 13,447-destroyed-rows-per-round report into silence — #323 reintroduced by its own fix. #629 re-audits on the unreconciled columns instead.

“Age wants mean” is superseded and marked so: the grain contract’s P2 requires every cell to hold an observed value or NA, and a mean is neither; and core’s last aggregation was retired at Site 2. Both are 2026-07-13 decisions postdating the note.

Scope

Comment-only. Country("Nigeria").data_scheme parses unchanged (24 tables). Note yaml.safe_load cannot read this file at all — it carries !make tags — so validate with the library loader, not plain YAML.

Refs #323, #498, #625, #627, #629.