models: Fix bug in unique_together condition on RealmPlayground.

We don't need to worry about breaking already configured playgrounds
since this tweak makes the condition less strict.

zerver/migrations/0325_alter_realmplayground_unique_together.py

@@ -0,0 +1,17 @@
+# Generated by Django 3.2.2 on 2021-05-13 00:16
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("zerver", "0324_fix_deletion_cascade_behavior"),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name="realmplayground",
+            unique_together={("realm", "pygments_language", "name")},
+        ),
+    ]

zerver/models.py

@@ -1038,7 +1038,7 @@ class RealmPlayground(models.Model):
     )
 
     class Meta:
-        unique_together = (("realm", "name"),)
+        unique_together = (("realm", "pygments_language", "name"),)
 
     def __str__(self) -> str:
         return f"<RealmPlayground({self.realm.string_id}): {self.pygments_language} {self.name}>"

zerver/tests/test_realm_playgrounds.py

@@ -77,7 +77,9 @@ class RealmPlaygroundTests(ZulipTestCase):
         self.assert_json_success(resp)
 
         resp = self.api_post(iago, "/json/realm/playgrounds", payload)
-        self.assert_json_error(resp, "Realm playground with this Realm and Name already exists.")
+        self.assert_json_error(
+            resp, "Realm playground with this Realm, Pygments language and Name already exists."
+        )
 
     def test_not_realm_admin(self) -> None:
         hamlet = self.example_user("hamlet")