models: Add State.slug field

This reduces a lot of the tech debt we had built up around this. This
field is populated from a slugified representation of State.name and has
a uniqueness constraint. As a result, we also need to a uniqueness
constraint to the State.name field. This shouldn't be an issue and
probably should have been used from day one.

Note that there is no REST API impact for this since we've been using
state slugs all along.

Signed-off-by: Stephen Finucane <stephen@that.guru>

7 files changed, 92 insertions, 23 deletions

diff --git a/patchwork/api/event.py b/patchwork/api/event.py
index e00ce05..a066faa 100644
--- a/patchwork/api/event.py
+++ b/patchwork/api/event.py
@@ -8,6 +8,7 @@ from collections import OrderedDict
 from rest_framework.generics import ListAPIView
 from rest_framework.serializers import ModelSerializer
 from rest_framework.serializers import SerializerMethodField
+from rest_framework.serializers import SlugRelatedField
 
 from patchwork.api.embedded import CheckSerializer
 from patchwork.api.embedded import CoverLetterSerializer
@@ -16,7 +17,6 @@ from patchwork.api.embedded import ProjectSerializer
 from patchwork.api.embedded import SeriesSerializer
 from patchwork.api.embedded import UserSerializer
 from patchwork.api.filters import EventFilterSet
-from patchwork.api.patch import StateField
 from patchwork.models import Event
 
 
@@ -27,8 +27,8 @@ class EventSerializer(ModelSerializer):
     patch = PatchSerializer(read_only=True)
     series = SeriesSerializer(read_only=True)
     cover = CoverLetterSerializer(read_only=True)
-    previous_state = StateField()
-    current_state = StateField()
+    previous_state = SlugRelatedField(slug_field='slug', read_only=True)
+    current_state = SlugRelatedField(slug_field='slug', read_only=True)
     previous_delegate = UserSerializer()
     current_delegate = UserSerializer()
     created_check = SerializerMethodField()
diff --git a/patchwork/api/patch.py b/patchwork/api/patch.py
index d1c9904..a29a1ab 100644
--- a/patchwork/api/patch.py
+++ b/patchwork/api/patch.py
@@ -5,6 +5,7 @@
 
 import email.parser
 
+from django.utils.text import slugify
 from django.utils.translation import ugettext_lazy as _
 from rest_framework.generics import ListAPIView
 from rest_framework.generics import RetrieveUpdateAPIView
@@ -28,10 +29,7 @@ from patchwork.parser import clean_subject
 class StateField(RelatedField):
     """Avoid the need for a state endpoint.
 
-    NOTE(stephenfin): This field will only function for State names consisting
-    of alphanumeric characters, underscores and single spaces. In Patchwork
-    2.0+, we should consider adding a slug field to the State object and make
-    use of the SlugRelatedField in DRF.
+    TODO(stephenfin): Consider switching to SlugRelatedField for the v2.0 API.
     """
     default_error_messages = {
         'required': _('This field is required.'),
@@ -41,19 +39,13 @@ class StateField(RelatedField):
                             '{data_type}.'),
     }
 
-    @staticmethod
-    def format_state_name(state):
-        return ' '.join(state.split('-'))
-
     def to_internal_value(self, data):
+        data = slugify(data.lower())
         try:
-            data = self.format_state_name(data)
-            return self.get_queryset().get(name__iexact=data)
+            return self.get_queryset().get(slug=data)
         except State.DoesNotExist:
             self.fail('invalid_choice', name=data, choices=', '.join([
-                self.format_state_name(x.name) for x in self.get_queryset()]))
-        except (TypeError, ValueError):
-            self.fail('incorrect_type', data_type=type(data).__name__)
+                x.slug for x in self.get_queryset()]))
 
     def to_representation(self, obj):
         return obj.slug
diff --git a/patchwork/fixtures/default_states.xml b/patchwork/fixtures/default_states.xml
index 86e1105..1bbd919 100644
--- a/patchwork/fixtures/default_states.xml
+++ b/patchwork/fixtures/default_states.xml
@@ -4,51 +4,61 @@
   <!-- default states -->
   <object pk="1" model="patchwork.state">
     <field type="CharField" name="name">New</field>
+    <field type="SlugField" name="name">new</field>
     <field type="IntegerField" name="ordering">0</field>
     <field type="BooleanField" name="action_required">True</field>
   </object>
   <object pk="2" model="patchwork.state">
     <field type="CharField" name="name">Under Review</field>
+    <field type="SlugField" name="name">under-review</field>
     <field type="IntegerField" name="ordering">1</field>
     <field type="BooleanField" name="action_required">True</field>
   </object>
   <object pk="3" model="patchwork.state">
     <field type="CharField" name="name">Accepted</field>
+    <field type="SlugField" name="name">accepted</field>
     <field type="IntegerField" name="ordering">2</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="4" model="patchwork.state">
     <field type="CharField" name="name">Rejected</field>
+    <field type="SlugField" name="name">rejected</field>
     <field type="IntegerField" name="ordering">3</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="5" model="patchwork.state">
     <field type="CharField" name="name">RFC</field>
+    <field type="SlugField" name="name">rfc</field>
     <field type="IntegerField" name="ordering">4</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="6" model="patchwork.state">
     <field type="CharField" name="name">Not Applicable</field>
+    <field type="SlugField" name="name">not-applicable</field>
     <field type="IntegerField" name="ordering">5</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="7" model="patchwork.state">
     <field type="CharField" name="name">Changes Requested</field>
+    <field type="SlugField" name="name">changes-requested</field>
     <field type="IntegerField" name="ordering">6</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="8" model="patchwork.state">
     <field type="CharField" name="name">Awaiting Upstream</field>
+    <field type="SlugField" name="name">awaiting-upstream</field>
     <field type="IntegerField" name="ordering">7</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="9" model="patchwork.state">
     <field type="CharField" name="name">Superseded</field>
+    <field type="SlugField" name="name">superseded</field>
     <field type="IntegerField" name="ordering">8</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
   <object pk="10" model="patchwork.state">
     <field type="CharField" name="name">Deferred</field>
+    <field type="SlugField" name="name">deferred</field>
     <field type="IntegerField" name="ordering">9</field>
     <field type="BooleanField" name="action_required">False</field>
   </object>
diff --git a/patchwork/migrations/0038_state_slug.py b/patchwork/migrations/0038_state_slug.py
new file mode 100644
index 0000000..500624d
--- /dev/null
+++ b/patchwork/migrations/0038_state_slug.py
@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+
+from __future__ import unicode_literals
+
+from django.db import migrations, models, transaction
+from django.utils.text import slugify
+
+
+def validate_uniqueness(apps, schema_editor):
+    """Ensure all State.name entries are unique.
+
+    We need to do this before enforcing a uniqueness constraint.
+    """
+
+    State = apps.get_model('patchwork', 'State')
+
+    total_count = State.objects.count()
+    slugs_count = len(set([
+        slugify(state.name) for state in State.objects.all()]))
+
+    if slugs_count != total_count:
+        raise Exception(
+            'You have non-unique States entries that need to be combined '
+            'before you can run this migration. This migration must be done '
+            'by hand. If you need assistance, please contact '
+            'patchwork@ozlabs.org')
+
+
+def populate_slug_field(apps, schema_editor):
+
+    State = apps.get_model('patchwork', 'State')
+
+    with transaction.atomic():
+        for state in State.objects.all():
+            state.slug = slugify(state.name)
+            state.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('patchwork', '0037_event_actor'),
+    ]
+
+    operations = [
+        # Ensure all 'State.name' entries are unique
+        migrations.RunPython(validate_uniqueness, migrations.RunPython.noop),
+        # Apply the unique constraint to 'State.name'
+        migrations.AlterField(
+            model_name='state',
+            name='name',
+            field=models.CharField(max_length=100, unique=True),
+        ),
+        # Add a 'State.slug' field but allow it to be nullable
+        migrations.AddField(
+            model_name='state',
+            name='slug',
+            field=models.SlugField(blank=True, max_length=100, null=True, unique=True),
+        ),
+        # Populate the 'State.slug' field
+        migrations.RunPython(populate_slug_field, migrations.RunPython.noop),
+        # Make the 'State.slug' field non-nullable
+        migrations.AlterField(
+            model_name='state',
+            name='slug',
+            field=models.SlugField(max_length=100, unique=True),
+        ),
+    ]
diff --git a/patchwork/models.py b/patchwork/models.py
index 7f0efd4..d95eb0d 100644
--- a/patchwork/models.py
+++ b/patchwork/models.py
@@ -215,14 +215,12 @@ models.signals.post_save.connect(_user_saved_callback, sender=User)
 
 @python_2_unicode_compatible
 class State(models.Model):
-    name = models.CharField(max_length=100)
+    # Both of these fields should be unique
+    name = models.CharField(max_length=100, unique=True)
+    slug = models.SlugField(max_length=100, unique=True)
     ordering = models.IntegerField(unique=True)
     action_required = models.BooleanField(default=True)
 
-    @property
-    def slug(self):
-        return '-'.join(self.name.lower().split())
-
     def __str__(self):
         return self.name
 
diff --git a/patchwork/tests/api/test_patch.py b/patchwork/tests/api/test_patch.py
index bf3ef9f..ef418e2 100644
--- a/patchwork/tests/api/test_patch.py
+++ b/patchwork/tests/api/test_patch.py
@@ -300,7 +300,7 @@ class TestPatchAPI(utils.APITestCase):
 
         self.client.force_authenticate(user=user)
         resp = self.client.patch(self.api_url(patch.id),
-                                 {'state': state.name, 'delegate': user.id})
+                                 {'state': state.slug, 'delegate': user.id})
         self.assertEqual(status.HTTP_200_OK, resp.status_code, resp)
         self.assertEqual(Patch.objects.get(id=patch.id).state, state)
         self.assertEqual(Patch.objects.get(id=patch.id).delegate, user)
@@ -326,7 +326,7 @@ class TestPatchAPI(utils.APITestCase):
         self.client.force_authenticate(user=user)
         resp = self.client.patch(self.api_url(patch.id), {'state': 'foobar'})
         self.assertEqual(status.HTTP_400_BAD_REQUEST, resp.status_code)
-        self.assertContains(resp, 'Expected one of: %s.' % state.name,
+        self.assertContains(resp, 'Expected one of: %s.' % state.slug,
                             status_code=status.HTTP_400_BAD_REQUEST)
 
     def test_update_legacy_delegate(self):
diff --git a/patchwork/tests/utils.py b/patchwork/tests/utils.py
index 577183d..91bcbe1 100644
--- a/patchwork/tests/utils.py
+++ b/patchwork/tests/utils.py
@@ -131,6 +131,7 @@ def create_state(**kwargs):
 
     values = {
         'name': 'state_%d' % num,
+        'slug': 'state-%d' % num,
         'ordering': num,
         'action_required': True,
     }