Setup deleted account

Pour pouvoir supprimer un compte, on crée un compte dummy qui a pour but
de recevoir les objets non supprimables (caisses, transferts/opérations
pour statistiques, etc.). Lors de la délétion d'un compte, tout est
transféré sur le dummy, qui est créé via migration.

kfet/__init__.py

@@ -1 +1,3 @@
 default_app_config = "kfet.apps.KFetConfig"
+KFET_DELETED_TRIGRAMME = "☠☠☠"
+KFET_DELETED_USERNAME = "kfet_deleted_user"

kfet/migrations/0067_deleted_account.py

@@ -0,0 +1,32 @@
+# Generated by Django 2.2 on 2019-05-23 13:54
+
+from django.db import migrations, models
+
+from kfet import KFET_DELETED_TRIGRAMME, KFET_DELETED_USERNAME
+
+
+def setup_kfet_deleted_user(apps, schema_editor):
+    """
+    Setup models instances for the kfet deleted account.
+
+    Username and trigramme are retrieved from kfet.__init__ module.
+    Other data are registered here.
+    """
+    User = apps.get_model("auth", "User")
+    CofProfile = apps.get_model("gestioncof", "CofProfile")
+    Account = apps.get_model("kfet", "Account")
+
+    user, _ = User.objects.update_or_create(
+        username=KFET_DELETED_USERNAME, defaults={"first_name": "Compte K-Fêt supprimé"}
+    )
+    profile, _ = CofProfile.objects.update_or_create(user=user)
+    account, _ = Account.objects.update_or_create(
+        cofprofile=profile, defaults={"trigramme": KFET_DELETED_TRIGRAMME}
+    )
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("kfet", "0066_on_delete_actions")]
+
+    operations = [migrations.RunPython(setup_kfet_deleted_user)]

kfet/migrations/0068_on_delete_account.py

@@ -0,0 +1,103 @@
+# Generated by Django 2.2 on 2019-05-23 16:17
+
+from django.db import migrations, models
+
+import kfet.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [("kfet", "0067_deleted_account")]
+
+    operations = [
+        migrations.AlterField(
+            model_name="checkout",
+            name="created_by",
+            field=models.ForeignKey(
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="+",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="checkoutstatement",
+            name="by",
+            field=models.ForeignKey(
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="+",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="inventory",
+            name="by",
+            field=models.ForeignKey(
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="+",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="operation",
+            name="addcost_for",
+            field=models.ForeignKey(
+                blank=True,
+                default=None,
+                null=True,
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="addcosts",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="operation",
+            name="canceled_by",
+            field=models.ForeignKey(
+                blank=True,
+                default=None,
+                null=True,
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="+",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="operationgroup",
+            name="on_acc",
+            field=models.ForeignKey(
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="opesgroup",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="transfer",
+            name="canceled_by",
+            field=models.ForeignKey(
+                blank=True,
+                default=None,
+                null=True,
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="+",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="transfer",
+            name="from_acc",
+            field=models.ForeignKey(
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="transfers_from",
+                to="kfet.Account",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="transfer",
+            name="to_acc",
+            field=models.ForeignKey(
+                on_delete=models.SET(kfet.models.get_deleted_account),
+                related_name="transfers_to",
+                to="kfet.Account",
+            ),
+        ),
+    ]

kfet/models.py

@@ -12,6 +12,7 @@ from django.utils.translation import ugettext_lazy as _
 
 from gestioncof.models import CofProfile
 
+from . import KFET_DELETED_TRIGRAMME
 from .auth import KFET_GENERIC_TRIGRAMME
 from .auth.models import GenericTeamToken  # noqa
 from .config import kfet_config
@@ -267,12 +268,6 @@ class Account(models.Model):
 
         self.password = hash_password(clear_password)
 
-    # Surcharge de delete
-    # Pas de suppression possible
-    # Cas à régler plus tard
-    def delete(self, *args, **kwargs):
-        pass
-
     def update_negative(self):
         if self.real_balance < 0:
             if hasattr(self, "negative") and not self.negative.start:
@@ -299,6 +294,10 @@ class Account(models.Model):
             self.trigramme = trigramme
 
 
+def get_deleted_account():
+    return Account.objects.get(trigramme=KFET_DELETED_TRIGRAMME)
+
+
 class AccountNegativeManager(models.Manager):
     """Manager for AccountNegative model."""
 
@@ -350,7 +349,9 @@ class CheckoutQuerySet(models.QuerySet):
 
 
 class Checkout(models.Model):
-    created_by = models.ForeignKey(Account, on_delete=models.PROTECT, related_name="+")
+    created_by = models.ForeignKey(
+        Account, on_delete=models.SET(get_deleted_account), related_name="+"
+    )
     name = models.CharField(max_length=45)
     valid_from = models.DateTimeField()
     valid_to = models.DateTimeField()
@@ -385,7 +386,9 @@ class Checkout(models.Model):
 
 
 class CheckoutStatement(models.Model):
-    by = models.ForeignKey(Account, on_delete=models.PROTECT, related_name="+")
+    by = models.ForeignKey(
+        Account, on_delete=models.SET(get_deleted_account), related_name="+"
+    )
     checkout = models.ForeignKey(
         Checkout, on_delete=models.CASCADE, related_name="statements"
     )
@@ -520,7 +523,9 @@ class Inventory(models.Model):
     articles = models.ManyToManyField(
         Article, through="InventoryArticle", related_name="inventories"
     )
-    by = models.ForeignKey(Account, on_delete=models.PROTECT, related_name="+")
+    by = models.ForeignKey(
+        Account, on_delete=models.SET(get_deleted_account), related_name="+"
+    )
     at = models.DateTimeField(auto_now_add=True)
     # Optional
     order = models.OneToOneField(
@@ -626,16 +631,18 @@ class Transfer(models.Model):
         TransferGroup, on_delete=models.PROTECT, related_name="transfers"
     )
     from_acc = models.ForeignKey(
-        Account, on_delete=models.PROTECT, related_name="transfers_from"
+        Account,
+        on_delete=models.SET(get_deleted_account),
+        related_name="transfers_from",
     )
     to_acc = models.ForeignKey(
-        Account, on_delete=models.PROTECT, related_name="transfers_to"
+        Account, on_delete=models.SET(get_deleted_account), related_name="transfers_to"
     )
     amount = models.DecimalField(max_digits=6, decimal_places=2)
     # Optional
     canceled_by = models.ForeignKey(
         Account,
-        on_delete=models.PROTECT,
+        on_delete=models.SET(get_deleted_account),
         null=True,
         blank=True,
         default=None,
@@ -649,7 +656,7 @@ class Transfer(models.Model):
 
 class OperationGroup(models.Model):
     on_acc = models.ForeignKey(
-        Account, on_delete=models.PROTECT, related_name="opesgroup"
+        Account, on_delete=models.SET(get_deleted_account), related_name="opesgroup"
     )
     checkout = models.ForeignKey(
         Checkout, on_delete=models.PROTECT, related_name="opesgroup"
@@ -706,7 +713,7 @@ class Operation(models.Model):
     article_nb = models.PositiveSmallIntegerField(blank=True, null=True, default=None)
     canceled_by = models.ForeignKey(
         Account,
-        on_delete=models.PROTECT,
+        on_delete=models.SET(get_deleted_account),
         related_name="+",
         blank=True,
         null=True,
@@ -715,7 +722,7 @@ class Operation(models.Model):
     canceled_at = models.DateTimeField(blank=True, null=True, default=None)
     addcost_for = models.ForeignKey(
         Account,
-        on_delete=models.PROTECT,
+        on_delete=models.SET(get_deleted_account),
         related_name="addcosts",
         blank=True,
         null=True,