feat: add BT-120 VAT exemption reason

[0xD0M1M0]

Adds a BT-120 textfield for the VAT exemption reason to the E-Invoice Settings: #183

[greptile-apps]

Greptile Summary

This PR implements BT-120 (VAT exemption reason text) support for the EU e-invoice module by adding a "Default VAT exemption reason" setting in E Invoice Settings and writing its value to the ram:ExemptionReason XML element on VAT breakdowns that already emit a BT-121 exemption reason code. It also supports round-tripping by reading BT-120 back from imported CII XML and storing it in the E Invoice Trade Tax child table, and includes a defensive guard in _set_seller_id to handle customers that lack a supplier_numbers attribute.

Confidence Score: 5/5

Safe to merge — the feature is correctly scoped, BT-120 text is only emitted alongside BT-121 code, and import round-tripping is handled consistently.

All changes are well-scoped: the exemption reason text is fetched once per invoice generation and applied only where the exemption reason code is already emitted, keeping BT-120 and BT-121 in sync. The import path is None-safe. No blocking issues were found.

No files require special attention.

Important Files Changed

Filename	Overview
eu_einvoice/european_e_invoice/custom/sales_invoice.py	Adds BT-120 exemption reason text to item-level and document-level zero-rate VAT breakdowns; new helper is only invoked where BT-121 reason code is already present, keeping the two fields in sync. Also adds a defensive getattr guard in _set_seller_id.
eu_einvoice/european_e_invoice/doctype/e_invoice_import/e_invoice_import.py	Reads tax.exemption_reason._text from parsed CII XML and stores it in the E Invoice Trade Tax child row; None-safe handling is correct.
eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.json	Adds a new VAT exemption (e-invoice) section with a Small Text field vat_exemption_reason_text; schema and description are accurate.
eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.json	Adds vat_exemption_reason_text (Small Text, read-only) to the child table used during invoice import; field order and auto-generated types are consistent.

Sequence Diagram

sequenceDiagram
    participant UI as E Invoice Settings UI
    participant DB as Frappe DB
    participant Gen as EInvoiceGenerator
    participant XML as CII XML

    UI->>DB: Save vat_exemption_reason_text (BT-120)

    note over Gen: create_einvoice()
    Gen->>DB: get_single_value("E Invoice Settings", "vat_exemption_reason_text")
    DB-->>Gen: reason_text (or "")

    alt Zero-rate item (rate == 0)
        Gen->>XML: set exemption_reason_code (BT-121)
        Gen->>XML: set exemption_reason (BT-120) via _set_optional_vat_exemption_reason_text
    end

    alt No taxes (empty invoice)
        Gen->>XML: set exemption_reason_code (BT-121)
        Gen->>XML: set exemption_reason (BT-120) via _set_optional_vat_exemption_reason_text
    end

    note over Gen: Import flow (e_invoice_import.py)
    XML-->>Gen: parse tax.exemption_reason._text
    Gen->>DB: store in E Invoice Trade Tax.vat_exemption_reason_text

Loading

_{Reviews (1): Last reviewed commit: "feat: add BT-120 VAT exemption reason" | Re-trigger Greptile}

[barredterra]

LGTM

[barredterra]

@Mergifyio backport version-16-hotfix version-15-hotfix

[mergify]

backport version-16-hotfix version-15-hotfix

✅ Backports have been created

Details

• #254 feat: add BT-120 VAT exemption reason (backport #247) has been created for branch version-16-hotfix but encountered conflicts

Cherry-pick of cec83b5 has failed:

On branch mergify/bp/version-16-hotfix/pr-247
Your branch is up to date with 'origin/version-16-hotfix'.

You are currently cherry-picking commit cec83b5.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   eu_einvoice/european_e_invoice/custom/sales_invoice.py
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_import/e_invoice_import.py
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.json
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.py
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.json
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.py

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   eu_einvoice/locale/de.po
	both modified:   eu_einvoice/locale/main.pot

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

• #255 feat: add BT-120 VAT exemption reason (backport #247) has been created for branch version-15-hotfix but encountered conflicts

Cherry-pick of cec83b5 has failed:

On branch mergify/bp/version-15-hotfix/pr-247
Your branch is up to date with 'origin/version-15-hotfix'.

You are currently cherry-picking commit cec83b5.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   eu_einvoice/european_e_invoice/custom/sales_invoice.py
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_import/e_invoice_import.py
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.json
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_settings/e_invoice_settings.py
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.json
	modified:   eu_einvoice/european_e_invoice/doctype/e_invoice_trade_tax/e_invoice_trade_tax.py

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   eu_einvoice/locale/de.po
	both modified:   eu_einvoice/locale/main.pot

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally