prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  Migrating to 1.1 Migration File Errors
  I am attempting to migrate to 1.1 and I am getting an error involving the migration files.
  
  ```
  Migration wagtailcore.0017_change_edit_page_permission_description dependencies reference nonexistent parent node (u'wagtailcore', u'0001_squashed_0016_change_page_url_path_to_text_field')
  ```
  
  The last migration for wagtail core in my migrations table is 0015. Since 0017 refers to 0001_squashed_0016 as a dependency and since I have not applied that migration, it's turn up as an error.
  
  I tried manually applying 0016, but the error is preventing that from happening.
  
  I know the issue queue is not intended for support questions, but I was speaking in the #django irc channel and they told me to check and see if the migrations were autogenerated. They said that normally migrations refer to the one before it and not the squashed ones.
  
  Migrating to 1.1 Migration File Errors
  I am attempting to migrate to 1.1 and I am getting an error involving the migration files.
  
  ```
  Migration wagtailcore.0017_change_edit_page_permission_description dependencies reference nonexistent parent node (u'wagtailcore', u'0001_squashed_0016_change_page_url_path_to_text_field')
  ```
  
  The last migration for wagtail core in my migrations table is 0015. Since 0017 refers to 0001_squashed_0016 as a dependency and since I have not applied that migration, it's turn up as an error.
  
  I tried manually applying 0016, but the error is preventing that from happening.
  
  I know the issue queue is not intended for support questions, but I was speaking in the #django irc channel and they told me to check and see if the migrations were autogenerated. They said that normally migrations refer to the one before it and not the squashed ones.
  
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py`
  Content:
  ```
  1 # -*- coding: utf-8 -*-
  2 from __future__ import unicode_literals
  3 
  4 from django.db import models, migrations
  5 
  6 
  7 class Migration(migrations.Migration):
  8 
  9     dependencies = [
  10         ('wagtailcore', '0001_squashed_0016_change_page_url_path_to_text_field'),
  11     ]
  12 
  13     operations = [
  14         migrations.AlterField(
  15             model_name='grouppagepermission',
  16             name='permission_type',
  17             field=models.CharField(choices=[('add', 'Add/edit pages you own'), ('edit', 'Edit any page'), ('publish', 'Publish any page'), ('lock', 'Lock/unlock any page')], max_length=20, verbose_name='Permission type'),
  18             preserve_default=True,
  19         ),
  20     ]
  21
  ```
  --- END FILES ---
  
  Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.
  
  Here is an example:
  
  ```diff
  diff --git a/examples/server_async.py b/examples/server_async.py
  --- a/examples/server_async.py
  +++ b/examples/server_async.py
  @@ -313,4 +313,4 @@
   
   
   if __name__ == "__main__":
  -    asyncio.run(run_async_server("."), debug=True)
  +    asyncio.run(run_async_server(), debug=True)
  diff --git a/examples/server_sync.py b/examples/server_sync.py
  --- a/examples/server_sync.py
  +++ b/examples/server_sync.py
  @@ -313,5 +313,5 @@
   
   
   if __name__ == "__main__":
  -    server = run_sync_server(".")
  +    server = run_sync_server()
       server.shutdown()
  
  ```
  
golden_diff: diff --git a/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py b/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py
  --- a/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py
  +++ b/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py
  @@ -7,7 +7,7 @@
   class Migration(migrations.Migration):
   
       dependencies = [
  -        ('wagtailcore', '0001_squashed_0016_change_page_url_path_to_text_field'),
  +        ('wagtailcore', '0016_change_page_url_path_to_text_field'),
       ]
   
       operations = [
  
verification_info: {"golden_diff": "diff --git a/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py b/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py\n--- a/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py\n+++ b/wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py\n@@ -7,7 +7,7 @@\n class Migration(migrations.Migration):\n \n     dependencies = [\n-        ('wagtailcore', '0001_squashed_0016_change_page_url_path_to_text_field'),\n+        ('wagtailcore', '0016_change_page_url_path_to_text_field'),\n     ]\n \n     operations = [\n", "issue": "Migrating to 1.1 Migration File Errors\nI am attempting to migrate to 1.1 and I am getting an error involving the migration files.\n\n```\nMigration wagtailcore.0017_change_edit_page_permission_description dependencies reference nonexistent parent node (u'wagtailcore', u'0001_squashed_0016_change_page_url_path_to_text_field')\n```\n\nThe last migration for wagtail core in my migrations table is 0015. Since 0017 refers to 0001_squashed_0016 as a dependency and since I have not applied that migration, it's turn up as an error.\n\nI tried manually applying 0016, but the error is preventing that from happening.\n\nI know the issue queue is not intended for support questions, but I was speaking in the #django irc channel and they told me to check and see if the migrations were autogenerated. They said that normally migrations refer to the one before it and not the squashed ones.\n\nMigrating to 1.1 Migration File Errors\nI am attempting to migrate to 1.1 and I am getting an error involving the migration files.\n\n```\nMigration wagtailcore.0017_change_edit_page_permission_description dependencies reference nonexistent parent node (u'wagtailcore', u'0001_squashed_0016_change_page_url_path_to_text_field')\n```\n\nThe last migration for wagtail core in my migrations table is 0015. Since 0017 refers to 0001_squashed_0016 as a dependency and since I have not applied that migration, it's turn up as an error.\n\nI tried manually applying 0016, but the error is preventing that from happening.\n\nI know the issue queue is not intended for support questions, but I was speaking in the #django irc channel and they told me to check and see if the migrations were autogenerated. They said that normally migrations refer to the one before it and not the squashed ones.\n\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\nfrom __future__ import unicode_literals\n\nfrom django.db import models, migrations\n\n\nclass Migration(migrations.Migration):\n\n    dependencies = [\n        ('wagtailcore', '0001_squashed_0016_change_page_url_path_to_text_field'),\n    ]\n\n    operations = [\n        migrations.AlterField(\n            model_name='grouppagepermission',\n            name='permission_type',\n            field=models.CharField(choices=[('add', 'Add/edit pages you own'), ('edit', 'Edit any page'), ('publish', 'Publish any page'), ('lock', 'Lock/unlock any page')], max_length=20, verbose_name='Permission type'),\n            preserve_default=True,\n        ),\n    ]\n", "path": "wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\nfrom __future__ import unicode_literals\n\nfrom django.db import models, migrations\n\n\nclass Migration(migrations.Migration):\n\n    dependencies = [\n        ('wagtailcore', '0016_change_page_url_path_to_text_field'),\n    ]\n\n    operations = [\n        migrations.AlterField(\n            model_name='grouppagepermission',\n            name='permission_type',\n            field=models.CharField(choices=[('add', 'Add/edit pages you own'), ('edit', 'Edit any page'), ('publish', 'Publish any page'), ('lock', 'Lock/unlock any page')], max_length=20, verbose_name='Permission type'),\n            preserve_default=True,\n        ),\n    ]\n", "path": "wagtail/wagtailcore/migrations/0017_change_edit_page_permission_description.py"}]}