fix git Results that are incorrect empty strings

Due to an error in the migration to populate Results for git, the data
field was set to an empty string rather than an empty dictionary.  Fix
this with another migration on top.  For simplicity I am using raw SQL
here.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Shubham Jain <shubhamjain7495@gmail.com>

api/migrations/0028_populate_git_results.py

@@ -34,23 +34,23 @@ def result_from_properties(apps, schema_editor):
             log_entry = LogEntry(data_xz=log_xz)
             log_entry.save()
             r.log_entry = log_entry
+            data = {}
             if get_property(MessageProperty, "git.apply-failed", message=m):
                 r.status = api.models.Result.FAILURE
             else:
                 git_repo = get_property(MessageProperty, "git.repo", message=m)
                 git_tag = get_property(MessageProperty, "git.tag", message=m)
                 git_url = get_property(MessageProperty, "git.url", message=m)
                 git_base = get_property(MessageProperty, "git.base", message=m)
-                data = {}
                 if git_repo and git_tag:
                     data['repo'] = git_repo
                     data['tag'] = 'refs/tags/' + git_tag
                     if git_url:
                         data['url'] = git_url
                     if git_base:
                         data['base'] = git_base
-                r.data = data
                 r.status = api.models.Result.SUCCESS
+            r.data = data
         else:
             status = api.models.Result.PENDING
         r.last_update = datetime.datetime.utcnow()

api/migrations/0032_fix_git_results.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.13 on 2018-07-11 12:17
+from __future__ import unicode_literals
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('api', '0031_auto_20180520_1654'),
+    ]
+
+    operations = [
+        # Due to an error in the migration to populate Results for git, the data
+        # field was set to an empty string rather than an empty dictionary.  This
+        # has been fixed now in the migration, but the fix is also included as a
+        # separate migration in case the buggy data is found in the database.
+        migrations.RunSQL("update api_result set data = '{}' where name='git' and data = '\"\"'")
+    ]

mods/git.py

@@ -276,10 +276,10 @@ def handle(self, request, project, message_id, tag, url, base, repo,
         r = Message.objects.series_heads().get(project=p,
                                                message_id=message_id).git_result
         r.log = log
+        data = {}
         if failed:
             r.status = Result.FAILURE
         else:
-            data = {}
             data['repo'] = repo
             data['tag'] = 'refs/tags/' + tag
             if url:
@@ -289,6 +289,6 @@ def handle(self, request, project, message_id, tag, url, base, repo,
                 data['url'] = url_template.replace("%t", tag)
             if base:
                 data['base'] = base
-            r.data = data
             r.status = Result.SUCCESS
+        r.data = data
         r.save()