[FIX] l10n_it_edi_ndd: prevent wrong value error

The computation of `l10n_it_document_type` fails when multiple
`l10n_it.document.type` records share the same code.
This can happen if a user duplicates an existing Document Type or creates a new
one with the same code, causing `get()` on the grouped recordset to return
multiple results.
This fix adds a check to ensure that the `code` field remains
unique across all `l10n_it.document.type` records.

Steps to Reproduce:

- Install the `l10n_it_edi_ndd` module.
- create a new invoice and confirm it.
- from `Electronic Invoicing` page, Open Document Type and duplicate it.
- Create another invoice and confirm it.

observation: you will receive a traceback for wrong value error

opw - 4902513

closes odoo#217155

Signed-off-by: Wala Gauthier (gawa) <[email protected]>

Author: suma-odoo

addons/l10n_it_edi_ndd/i18n/it.po

@@ -75,6 +75,13 @@ msgstr "Nome visualizzato"
 msgid "Document Type"
 msgstr "Tipi di documento"
 
+#. module: l10n_it_edi_ndd
+#. odoo-python
+#: code:addons/l10n_it_edi_ndd/models/l10n_it_document_type.py:0
+#, python-format
+msgid "Document Type code must be unique."
+msgstr "Il codice del tipo di documento deve essere univoco."
+
 #. module: l10n_it_edi_ndd
 #: model:ir.model.fields,field_description:l10n_it_edi_ndd.field_l10n_it_document_type__id
 msgid "ID"

addons/l10n_it_edi_ndd/i18n/l10n_it_edi_ndd.pot

@@ -75,6 +75,13 @@ msgstr ""
 msgid "Document Type"
 msgstr ""
 
+#. module: l10n_it_edi_ndd
+#. odoo-python
+#: code:addons/l10n_it_edi_ndd/models/l10n_it_document_type.py:0
+#, python-format
+msgid "Document Type code must be unique."
+msgstr ""
+
 #. module: l10n_it_edi_ndd
 #: model:ir.model.fields,field_description:l10n_it_edi_ndd.field_l10n_it_document_type__id
 msgid "ID"

addons/l10n_it_edi_ndd/models/l10n_it_document_type.py

@@ -1,4 +1,5 @@
-from odoo import fields, models
+from odoo import _, api, fields, models
+from odoo.exceptions import ValidationError
 
 
 class L10nItDocumentType(models.Model):
@@ -18,3 +19,15 @@ class L10nItDocumentType(models.Model):
     def _compute_display_name(self):
         for document_type in self:
             document_type.display_name = f"{document_type.code} - {document_type.name}"
+
+    @api.constrains('code')
+    def _check_code_unique(self):
+        duplicate = self._read_group(
+            domain=[],
+            groupby=['code'],
+            aggregates=['id:recordset'],
+            having=[('__count', '>', 1)],
+            limit=1,
+        )
+        if duplicate:
+            raise ValidationError(_('Document Type code must be unique.'))