Move the Sales Invoice withholding fields and both Property Setters from
fixtures to default_thai_company/custom/{sales_invoice,payment_entry}.json
with sync_on_migrate. sync_customizations updates Custom Fields in place
instead of the delete/re-insert that fixtures do on every migrate.
Custom fields Tax Withholding Category (fetched from Customer),
Withholding Tax and Net Payable After Withholding Tax on Sales Invoice;
computed in the Thai set_tax_withholding override from the category
rate and single threshold, informational only (totals/GL unchanged),
printed under Rounded Total by the standard layout. Payment Entry now
prefers each invoice's category over the customer's.
Integration tests on a throwaway Thai company: account creation and
category linking on Company insert, site-configured account surviving
fixture re-import, Sales Invoice left un-grossed, and Payment Entry
deductions (full, prorated, below threshold, unchecked). Run with
CI=1 bench --site <site> run-tests --app default_thai_company.
Thai customers withhold tax at payment; ERPNext's customer-side handling
is Indian TCS which adds tax on top of the Sales Invoice. Override
SalesInvoice.set_tax_withholding to no-op for Thai companies, expose
"Apply Tax Withholding Amount" on Customer/Receive Payment Entries, and
on validate compute rate x pre-VAT amount of each allocated reference
(prorated, single threshold honoured) as a deduction to "Withholding Tax
Receivable". Client script fetches the Customer's category when the box
is ticked.
Add 22 Tax Withholding Category fixtures covering Thailand domestic
withholding (Taw.Paw. 4/2528, Sec. 50(2), Sec. 70) with rates and
thresholds. Fixtures ship without accounts; on import each Thai company
gets "Withholding Tax Payable" (Liability) and "Withholding Tax
Receivable" (Asset) created and the payable account linked. Company
on_update does the same for companies created later. Site-configured
accounts survive fixture re-import on migrate.
kurogeek