Allow closing protected legacy NCF ranges

README.rst

@@ -43,6 +43,11 @@ same document direction.  The last issued number automatically finishes the
 line.  Finishing an authorization closes every remaining active line without
 reusing numbers.
 
+Legacy migration lines keep their original technical sequence immutable after
+activation.  Prefix selection is enforced while a line is in draft and fiscal
+activation performs the same server-side validation; closing a protected
+historical line therefore does not invalidate already-linked invoices.
+
 Electronic fiscal numbers are only reserved by this module.  Activating an
 E-series authorization never signs or transmits an e-CF to DGII.
 

ncf_manager.py

@@ -8,7 +8,7 @@ from trytond.i18n import gettext
 
 from trytond.model import ModelView, ModelSQL, Workflow, fields, Unique
 from trytond.pool import Pool
-from trytond.pyson import Eval
+from trytond.pyson import Eval, If
 from trytond.transaction import Transaction
 
 
@@ -309,7 +309,9 @@ class NCFManagerSequences(Workflow, ModelSQL, ModelView):
     ncf_sequences = fields.Many2One('ir.sequence.strict', 'Fiscal Sequence',
         domain=[
             ('company', '=', Eval('company', -1)),
+            If(Eval('state') == 'draft',
                 ('prefix', '=', Eval('expected_prefix')),
+                ()),
             ('active', '=', True),
         ],
         states={

tests/test_module.py

@@ -396,6 +396,28 @@ class NcfManagerTestCase(ModuleTestCase):
         with self.assertRaises(UserError):
             Manager.activate([manager])
 
+    @with_transaction()
+    def test_finish_preserves_bound_legacy_migration_sequence(self):
+        'Finishing must not invalidate an immutable historical sequence'
+        pool = Pool()
+        Manager = pool.get('ncf.manager')
+        StrictSequence = pool.get('ir.sequence.strict')
+        company = self._create_company()
+
+        line = self._create_ncf_sequence(company)
+        strict_sequence = line.ncf_sequences
+        StrictSequence.write([strict_sequence], {
+                'prefix': 'MIG1',
+                'padding': 9,
+                })
+
+        Manager.finish([line.pos])
+
+        line = line.__class__(line.id)
+        self.assertEqual(line.state, 'finished')
+        self.assertEqual(line.ncf_sequences.id, strict_sequence.id)
+        self.assertEqual(line.ncf_sequences.prefix, 'MIG1')
+
     @with_transaction()
     def test_import_dgii_authorization_is_idempotent(self):
         pool = Pool()

tryton.cfg

@@ -1,5 +1,5 @@
 [tryton]
-version=8.0.2
+version=8.0.3
 depends:
 	account_do
 	account_invoice_do