feat(certificates): multiple Default CoC Contacts per customer (M2o -> M2m)

res.partner.x_fc_default_coc_contact_id (single Many2one) becomes
x_fc_default_coc_contact_ids (self-referential Many2many 'Default CoC
Contacts') so a customer can list several contacts who need the CoC.

- res.partner: M2m field (rel fp_default_coc_contact_rel) + many2many_tags.
- Cert: contact_partner_id (primary addressee printed on the cert) is set to
  the FIRST CoC contact at job creation + lazy-filled at issue.
- Send: action_send_to_customer pre-fills the email composer with ALL the
  customer's CoC contacts (primary + the rest), falling back to the company.
- fp.job cert-default resolution + the action_issue gate wording updated.
- Migration 19.0.10.2.0: copies each partner's old single value into the new
  M2m, then drops the orphaned column.

Deployed + verified on entech: migration copied 2 existing values, old column
dropped, field is M2m, send pre-fills all contacts. entech-only part_line_ids
/ multi-part resolver preserved.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

fusion_plating/fusion_plating_certificates/__manifest__.py

@@ -5,7 +5,7 @@
 
 {
     'name': 'Fusion Plating — Certificates',
-    'version': '19.0.9.4.0',
+    'version': '19.0.10.2.0',
     'category': 'Manufacturing/Plating',
     'summary': 'Certificate registry for CoC, thickness reports, and quality documents.',
     'description': """

fusion_plating/fusion_plating_certificates/migrations/19.0.10.2.0/post-migrate.py

@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+# Copyright 2026 Nexa Systems Inc.
+# License OPL-1
+"""Migrate the single Default CoC Contact (Many2one) to the multi-contact
+Many2many.
+
+The field x_fc_default_coc_contact_id (Many2one column on res_partner) was
+renamed to x_fc_default_coc_contact_ids (self-referential Many2many, rel
+table fp_default_coc_contact_rel). Odoo creates the new rel table during the
+schema-update phase but leaves the old column orphaned. Copy each partner's
+single contact into the new M2m so existing per-customer CoC routing carries
+over, then drop the dead column. Idempotent + guarded on column existence.
+"""
+import logging
+
+_logger = logging.getLogger(__name__)
+
+
+def migrate(cr, version):
+    # Old column still present (Odoo doesn't drop removed-field columns)?
+    cr.execute("""
+        SELECT 1 FROM information_schema.columns
+         WHERE table_name = 'res_partner'
+           AND column_name = 'x_fc_default_coc_contact_id'
+    """)
+    if not cr.fetchone():
+        return
+    # New M2m rel table created by the schema update before this runs.
+    cr.execute("""
+        SELECT 1 FROM information_schema.tables
+         WHERE table_name = 'fp_default_coc_contact_rel'
+    """)
+    if not cr.fetchone():
+        _logger.warning(
+            'fp_default_coc_contact_rel missing — skipping CoC contact '
+            'migration (rel table not created yet).')
+        return
+    # Copy the single value into the M2m (skip rows already present so a
+    # re-run is harmless).
+    cr.execute("""
+        INSERT INTO fp_default_coc_contact_rel (partner_id, contact_id)
+        SELECT p.id, p.x_fc_default_coc_contact_id
+          FROM res_partner p
+         WHERE p.x_fc_default_coc_contact_id IS NOT NULL
+           AND NOT EXISTS (
+               SELECT 1 FROM fp_default_coc_contact_rel r
+                WHERE r.partner_id = p.id
+                  AND r.contact_id = p.x_fc_default_coc_contact_id)
+    """)
+    moved = cr.rowcount
+    cr.execute(
+        "ALTER TABLE res_partner DROP COLUMN IF EXISTS "
+        "x_fc_default_coc_contact_id")
+    _logger.info(
+        'CoC contact migration: copied %s single Default-CoC-Contact value(s) '
+        'into the new x_fc_default_coc_contact_ids M2m, dropped old column.',
+        moved)

fusion_plating/fusion_plating_certificates/models/fp_certificate.py

@@ -521,10 +521,12 @@ class FpCertificate(models.Model):
             # effect retroactively at issue time.
             if (not rec.contact_partner_id
                     and rec.partner_id
-                    and 'x_fc_default_coc_contact_id' in rec.partner_id._fields
+                    and 'x_fc_default_coc_contact_ids' in rec.partner_id._fields
-                    and rec.partner_id.x_fc_default_coc_contact_id):
+                    and rec.partner_id.x_fc_default_coc_contact_ids):
+                # Primary = first of the customer's CoC contacts; the rest
+                # are CC'd at send (action_send_to_customer).
                 rec.contact_partner_id = (
-                    rec.partner_id.x_fc_default_coc_contact_id
+                    rec.partner_id.x_fc_default_coc_contact_ids[:1]
                 )
             # Lazy-fill the signer from the LIVE company owner (Settings
             # "Certificate Owner") when no per-cert / per-spec signer was
@@ -578,13 +580,13 @@ class FpCertificate(models.Model):
                     '(Settings > Fusion Plating).'
                 ) % {'name': rec.name or rec.display_name})
             # Customer contact — the named recipient printed on the
-            # cert and emailed when it ships. Auto-filled from
+            # cert and emailed when it ships. Auto-filled from the FIRST
-            # partner.x_fc_default_coc_contact_id when set.
+            # of partner.x_fc_default_coc_contact_ids when set.
             if not rec.contact_partner_id:
                 raise UserError(_(
                     'Cannot issue certificate "%(name)s" — Customer '
                     'Contact is not set.\n\nPick the recipient contact, '
-                    'or configure a Default CoC Contact on customer '
+                    'or configure Default CoC Contacts on customer '
                     '"%(cust)s".'
                 ) % {
                     'name': rec.name or rec.display_name,
@@ -1114,11 +1116,21 @@ class FpCertificate(models.Model):
         """Open email composer with the certificate PDF attached."""
         self.ensure_one()
         template = self.env.ref('mail.email_compose_message_wizard_form', raise_if_not_found=False)
+        # CoC goes to ALL the customer's CoC contacts (the cert's primary
+        # contact + the rest of partner.x_fc_default_coc_contact_ids),
+        # falling back to the company. Every contact who needs the cert is
+        # pre-filled on the composer.
+        recipients = self.contact_partner_id
+        if (self.partner_id
+                and 'x_fc_default_coc_contact_ids' in self.partner_id._fields):
+            recipients |= self.partner_id.x_fc_default_coc_contact_ids
+        partner_ids = recipients.ids or (
+            [self.partner_id.id] if self.partner_id else [])
         ctx = {
             'default_model': 'fp.certificate',
             'default_res_ids': self.ids,
             'default_composition_mode': 'comment',
-            'default_partner_ids': [self.partner_id.id] if self.partner_id else [],
+            'default_partner_ids': partner_ids,
         }
         if self.attachment_id:
             ctx['default_attachment_ids'] = [self.attachment_id.id]

fusion_plating/fusion_plating_certificates/models/res_partner.py

@@ -128,17 +128,24 @@ class ResPartner(models.Model):
              'who require specific NIST or DFARS language.',
     )
 
-    # ---- Default CoC contact (cert addressee + email recipient) ----------
+    # ---- Default CoC contacts (cert addressees + email recipients) -------
-    # The single named contact printed on the CoC and used as the email
+    # One or more named contacts who receive this customer's CoC. The first
-    # default when the cert ships. Sales sets it once per customer.
+    # is the primary (printed on the cert + pre-fills cert.contact_partner_id
-    # Falls back to manual selection at action_issue time if blank.
+    # when a job ships); the rest are CC'd when the CoC is emailed. Sales
-    x_fc_default_coc_contact_id = fields.Many2one(
+    # sets the list once per customer. Falls back to manual selection at
+    # action_issue time if blank. Self-referential M2m (renamed from the old
+    # single Many2one x_fc_default_coc_contact_id — see migration 19.0.10.2.0).
+    x_fc_default_coc_contact_ids = fields.Many2many(
         'res.partner',
-        string='Default CoC Contact',
+        relation='fp_default_coc_contact_rel',
+        column1='partner_id', column2='contact_id',
+        string='Default CoC Contacts',
         domain="[('parent_id', '=', id), ('is_company', '=', False)]",
         tracking=True,
-        help='Default contact the Certificate of Conformance is addressed '
+        help='Contacts the Certificate of Conformance is addressed to and '
-             'to and emailed to. Pre-fills cert.contact_partner_id when a '
+             'emailed to. The first contact is the primary (printed on the '
-             'job ships. Leave blank to force the manager to pick at '
+             'cert and pre-filled as the cert contact when a job ships); '
-             'issue time. Must be a child contact of this company.',
+             'the rest are copied (CC) when the CoC is sent. Leave blank to '
+             'force the manager to pick at issue time. Child contacts of '
+             'this company only.',
     )

fusion_plating/fusion_plating_certificates/views/res_partner_views.xml

@@ -44,15 +44,17 @@
                             <field name="x_fc_send_customer_specific" widget="boolean_toggle"/>
                         </group>
                     </group>
-                    <separator string="Default CoC Contact"/>
+                    <separator string="Default CoC Contacts"/>
                     <p class="text-muted">
-                        The named contact this customer's CoC is addressed
+                        The contacts this customer's CoC is addressed to and
-                        to and emailed to. Pre-fills cert records when a
+                        emailed to. The first is the primary (printed on the
-                        job ships. Leave blank to force the manager to pick
+                        cert); the rest are copied (CC) when the CoC is sent.
-                        at issue time.
+                        Pre-fills cert records when a job ships. Leave blank
+                        to force the manager to pick at issue time.
                     </p>
                     <group>
-                        <field name="x_fc_default_coc_contact_id"
+                        <field name="x_fc_default_coc_contact_ids"
+                               widget="many2many_tags"
                                options="{'no_create': True}"/>
                     </group>
                     <separator string="Cert Statement Override (Sub 12c+)"/>

fusion_plating/fusion_plating_jobs/models/fp_job.py

@@ -2678,7 +2678,7 @@ class FpJob(models.Model):
                                   (a per-spec override). Left empty
                                   otherwise so the LIVE company owner
                                   resolves at render / issue time.
-          - contact_partner_id  ← partner.x_fc_default_coc_contact_id
+          - contact_partner_id  ← partner.x_fc_default_coc_contact_ids[:1]
           - nc_quantity         ← qty_scrapped + qty_visual_insp_rejects
 
         Honours part.certificate_requirement (coc / coc_thickness /
@@ -2713,8 +2713,10 @@ class FpJob(models.Model):
             signer = spec.signer_user_id
         # Contact: per-customer default; blank means manager picks at issue.
         contact = False
-        if 'x_fc_default_coc_contact_id' in self.partner_id._fields:
+        if 'x_fc_default_coc_contact_ids' in self.partner_id._fields:
-            contact = self.partner_id.x_fc_default_coc_contact_id
+            # Primary = first of the customer's CoC contacts; the rest are
+            # CC'd at send (fp.certificate.action_send_to_customer).
+            contact = self.partner_id.x_fc_default_coc_contact_ids[:1]
         # NC qty: scrapped + visual rejects. Both NULL-safe.
         nc_qty = int(
             (self.qty_scrapped or 0)

fusion_plating/fusion_plating_jobs/tests/test_fp_job_milestone_cascade.py

@@ -617,7 +617,7 @@ class TestCertCreationAndGates(TransactionCase):
             'name':          'CertCust',
             'is_company':    True,
             'x_fc_send_coc': True,
-            'x_fc_default_coc_contact_id': cls.contact.id,
+            'x_fc_default_coc_contact_ids': [(6, 0, [cls.contact.id])],
         })
         cls.contact.parent_id = cls.partner.id
         cls.product = cls.env['product.product'].create({