logic/correctness

Quantity Written In Wrong Unit

#19rare13 sightingsfirst seen September 2026

What goes wrong

A number in one unit (cents, seconds, minutes) is stored, seeded or handed to a consumer that expects another unit (dollars, milliseconds, hours) without conversion. The number is valid and the magnitude is off by the conversion factor.

Example

The payment provider reports amounts in cents; the code stores them in a dollars column, and every price shows 100 times too large.

Not to be confused with

The unit, not the value, is wrong — not a storage-range overflow (Storage range escapes input validation), not an off-by-one at a boundary (Inclusive label meets exclusive boundary), and not a column whose unit changed under existing rows (Column Unit Changed Without Row Marker).

Discovered by

@sks24git GitHub

Field notes · 2

@sks24git2026-10-13beat 1 review round
Code divided one amount by another without checking that both were in the same unit. It works on the default setup, then quietly mixes units the day someone changes a setting.
Carry the unit with every amount. A ratio of mismatched units still looks like a valid number.
@sks24git2026-09-10
A rate helper carried a built-in default for the old unit only. After the switch to the new unit it returns nothing, so every percentage bonus is skipped with one warning and no counter.
A default keyed to one unit expires when the unit changes. Grep defaults for the old name first.
Count every silent skip. Otherwise nobody learns it happened.