Add __str__ to models, remove null=True in CharField and TextField

apps/note/migrations/0003_replace_null_by_blank.py

@@ -0,0 +1,17 @@
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('note', '0002_create_special_notes'),
+    ]
+
+    operations = [
+        migrations.RunSQL(
+            "UPDATE note_note SET inactivity_reason = '' WHERE inactivity_reason IS NULL;"
+        ),
+        migrations.RunSQL(
+            "UPDATE note_transaction SET invalidity_reason = '' WHERE invalidity_reason IS NULL;"
+        ),
+    ]

apps/note/migrations/0004_remove_null_tag_on_charfields.py

@@ -0,0 +1,23 @@
+# Generated by Django 2.2.16 on 2020-09-06 19:17
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('note', '0003_replace_null_by_blank'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='note',
+            name='inactivity_reason',
+            field=models.CharField(blank=True, choices=[('manual', 'The user blocked his/her note manually, eg. when he/she left the school for holidays. It can be reactivated at any time.'), ('forced', "The note is blocked by the the BDE and can't be manually reactivated.")], default='', max_length=255),
+        ),
+        migrations.AlterField(
+            model_name='transaction',
+            name='invalidity_reason',
+            field=models.CharField(blank=True, default='', max_length=255, verbose_name='invalidity reason'),
+        ),
+    ]

apps/note/models/notes.py

@@ -70,8 +70,8 @@ class Note(PolymorphicModel):
                          "It can be reactivated at any time.")),
             ('forced', _("The note is blocked by the the BDE and can't be manually reactivated.")),
         ],
-        null=True,
-        default=None,
+        blank=True,
+        default="",
     )
 
     class Meta:

apps/note/models/transactions.py

@@ -90,6 +90,9 @@ class TransactionTemplate(models.Model):
     def get_absolute_url(self):
         return reverse('note:template_update', args=(self.pk,))
 
+    def __str__(self):
+        return self.name
+
 
 class Transaction(PolymorphicModel):
     """
@@ -150,8 +153,7 @@ class Transaction(PolymorphicModel):
     invalidity_reason = models.CharField(
         verbose_name=_('invalidity reason'),
         max_length=255,
-        default=None,
-        null=True,
+        default='',
         blank=True,
     )
 
@@ -195,7 +197,7 @@ class Transaction(PolymorphicModel):
 
             # When a transaction is declared valid, we ensure that the invalidity reason is null, if it was
             # previously invalid
-            self.invalidity_reason = None
+            self.invalidity_reason = ""
 
         if source_balance > 9223372036854775807 or source_balance < -9223372036854775808\
                 or dest_balance > 9223372036854775807 or dest_balance < -9223372036854775808: