project_code was a text copy of the parent site's code, denormalised
onto 8 child collections that each already have a real site relation.
Written once at insert, never updated -- docs/data-model.md documents
the drift risk. On purchase_orders it never even held a real project
code: production had requisition numbers, site names, and the PO's own
number in that field.
Every read site now resolves the code through site/expand.site/siteById
instead, reusing each page's existing site map where one already
existed. Every create() call stops writing the column. The chat agent's
list_imports tool no longer reads data_import_batches -- it now reads
timesheets, fuel_sheets, plant_hours_sheets, purchase_orders and
delivery_notes filtered by processing_status, which was necessary before
the pool can be dropped (Task 20 would otherwise 404 the agent).
Also closed a Task 17 gap found while doing this: the agent tools' vehicle
and fuel-log handlers still resolved project code from the now-removed
vehicles.project_code column.
Wrote scripts/migrations/2026-09-15-drop-legacy-columns.py, the one
irreversible step in this whole restructure. Its guard against orphaning
fuel_logs rows checked the wrong condition -- "fuel_sheet is empty" --
which produced a false abort: 73 fuel_logs rows have no fuel_sheet
because they predate batch tracking entirely and never had a
batch_reference to begin with, so dropping data_import_batches costs
them nothing. Fixed the guard to check what it actually claims to check:
a row that HAD a batch_reference and was never relinked. Verified live
that no such row exists on any of the three affected collections.
Script run in dry-run only; not yet applied.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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