prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  Inconsistency with 404 response on empty collections
  - Set `read_only` to true
  - Give readonly access to the postgresql user
  - Give `read` permission to everyone on a bucket `foo`
  - Going to `/buckets/foo/collections/unknown` gives 404
  - Going to `/buckets/foo/collections/unknown/records` gives 503
  
  Listing the records of an unknown collection should definitely give 404, except with the `default` bucket plugin.
  
  Very related to https://github.com/Kinto/kinto/issues/558
  
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `kinto/views/records.py`
  Content:
  ```
  1 import copy
  2 
  3 import jsonschema
  4 from kinto.core import resource
  5 from kinto.core.errors import raise_invalid
  6 from jsonschema import exceptions as jsonschema_exceptions
  7 from pyramid.security import Authenticated
  8 from pyramid.settings import asbool
  9 
  10 from kinto.views import RelaxedUUID, object_exists_or_404
  11 
  12 
  13 class RecordSchema(resource.ResourceSchema):
  14     class Options:
  15         preserve_unknown = True
  16 
  17 
  18 _parent_path = '/buckets/{{bucket_id}}/collections/{{collection_id}}'
  19 
  20 
  21 @resource.register(name='record',
  22                    collection_path=_parent_path + '/records',
  23                    record_path=_parent_path + '/records/{{id}}')
  24 class Record(resource.ShareableResource):
  25 
  26     mapping = RecordSchema()
  27     schema_field = 'schema'
  28 
  29     def __init__(self, *args, **kwargs):
  30         super(Record, self).__init__(*args, **kwargs)
  31 
  32         self.model.id_generator = RelaxedUUID()
  33 
  34         # Check if already fetched before (in batch).
  35         collections = self.request.bound_data.setdefault('collections', {})
  36         collection_uri = self.get_parent_id(self.request)
  37         if collection_uri not in collections:
  38             # Unknown yet, fetch from storage.
  39             collection_parent_id = '/buckets/%s' % self.bucket_id
  40             collection = object_exists_or_404(self.request,
  41                                               collection_id='collection',
  42                                               parent_id=collection_parent_id,
  43                                               object_id=self.collection_id)
  44             collections[collection_uri] = collection
  45 
  46         self._collection = collections[collection_uri]
  47 
  48     def get_parent_id(self, request):
  49         self.bucket_id = request.matchdict['bucket_id']
  50         self.collection_id = request.matchdict['collection_id']
  51         return '/buckets/%s/collections/%s' % (self.bucket_id,
  52                                                self.collection_id)
  53 
  54     def is_known_field(self, field_name):
  55         """Without schema, any field is considered as known."""
  56         return True
  57 
  58     def process_record(self, new, old=None):
  59         """Validate records against collection schema, if any."""
  60         new = super(Record, self).process_record(new, old)
  61 
  62         schema = self._collection.get('schema')
  63         settings = self.request.registry.settings
  64         schema_validation = 'experimental_collection_schema_validation'
  65         if not schema or not asbool(settings.get(schema_validation)):
  66             return new
  67 
  68         collection_timestamp = self._collection[self.model.modified_field]
  69 
  70         try:
  71             stripped = copy.deepcopy(new)
  72             stripped.pop(self.model.id_field, None)
  73             stripped.pop(self.model.modified_field, None)
  74             stripped.pop(self.model.permissions_field, None)
  75             stripped.pop(self.schema_field, None)
  76             jsonschema.validate(stripped, schema)
  77         except jsonschema_exceptions.ValidationError as e:
  78             try:
  79                 field = e.path.pop() if e.path else e.validator_value.pop()
  80             except AttributeError:
  81                 field = None
  82             raise_invalid(self.request, name=field, description=e.message)
  83 
  84         new[self.schema_field] = collection_timestamp
  85         return new
  86 
  87     def collection_get(self):
  88         result = super(Record, self).collection_get()
  89         self._handle_cache_expires(self.request.response)
  90         return result
  91 
  92     def get(self):
  93         result = super(Record, self).get()
  94         self._handle_cache_expires(self.request.response)
  95         return result
  96 
  97     def _handle_cache_expires(self, response):
  98         """If the parent collection defines a ``cache_expires`` attribute,
  99         then cache-control response headers are sent.
  100 
  101         .. note::
  102 
  103             Those headers are also sent if the
  104             ``kinto.record_cache_expires_seconds`` setting is defined.
  105         """
  106         is_anonymous = Authenticated not in self.request.effective_principals
  107         if not is_anonymous:
  108             return
  109 
  110         cache_expires = self._collection.get('cache_expires')
  111         if cache_expires is None:
  112             by_bucket = '%s_record_cache_expires_seconds' % (self.bucket_id)
  113             by_collection = '%s_%s_record_cache_expires_seconds' % (
  114                 self.bucket_id, self.collection_id)
  115             settings = self.request.registry.settings
  116             cache_expires = settings.get(by_collection,
  117                                          settings.get(by_bucket))
  118 
  119         if cache_expires is not None:
  120             response.cache_expires(seconds=int(cache_expires))
  121
  ```
  --- 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/kinto/views/records.py b/kinto/views/records.py
  --- a/kinto/views/records.py
  +++ b/kinto/views/records.py
  @@ -26,23 +26,22 @@
       mapping = RecordSchema()
       schema_field = 'schema'
   
  -    def __init__(self, *args, **kwargs):
  -        super(Record, self).__init__(*args, **kwargs)
  -
  -        self.model.id_generator = RelaxedUUID()
  -
  +    def __init__(self, request, **kwargs):
  +        # Before all, first check that the parent collection exists.
           # Check if already fetched before (in batch).
  -        collections = self.request.bound_data.setdefault('collections', {})
  -        collection_uri = self.get_parent_id(self.request)
  +        collections = request.bound_data.setdefault('collections', {})
  +        collection_uri = self.get_parent_id(request)
           if collection_uri not in collections:
               # Unknown yet, fetch from storage.
               collection_parent_id = '/buckets/%s' % self.bucket_id
  -            collection = object_exists_or_404(self.request,
  +            collection = object_exists_or_404(request,
                                                 collection_id='collection',
                                                 parent_id=collection_parent_id,
                                                 object_id=self.collection_id)
               collections[collection_uri] = collection
   
  +        super(Record, self).__init__(request, **kwargs)
  +        self.model.id_generator = RelaxedUUID()
           self._collection = collections[collection_uri]
   
       def get_parent_id(self, request):
  
verification_info: {"golden_diff": "diff --git a/kinto/views/records.py b/kinto/views/records.py\n--- a/kinto/views/records.py\n+++ b/kinto/views/records.py\n@@ -26,23 +26,22 @@\n     mapping = RecordSchema()\n     schema_field = 'schema'\n \n-    def __init__(self, *args, **kwargs):\n-        super(Record, self).__init__(*args, **kwargs)\n-\n-        self.model.id_generator = RelaxedUUID()\n-\n+    def __init__(self, request, **kwargs):\n+        # Before all, first check that the parent collection exists.\n         # Check if already fetched before (in batch).\n-        collections = self.request.bound_data.setdefault('collections', {})\n-        collection_uri = self.get_parent_id(self.request)\n+        collections = request.bound_data.setdefault('collections', {})\n+        collection_uri = self.get_parent_id(request)\n         if collection_uri not in collections:\n             # Unknown yet, fetch from storage.\n             collection_parent_id = '/buckets/%s' % self.bucket_id\n-            collection = object_exists_or_404(self.request,\n+            collection = object_exists_or_404(request,\n                                               collection_id='collection',\n                                               parent_id=collection_parent_id,\n                                               object_id=self.collection_id)\n             collections[collection_uri] = collection\n \n+        super(Record, self).__init__(request, **kwargs)\n+        self.model.id_generator = RelaxedUUID()\n         self._collection = collections[collection_uri]\n \n     def get_parent_id(self, request):\n", "issue": "Inconsistency with 404 response on empty collections\n- Set `read_only` to true\n- Give readonly access to the postgresql user\n- Give `read` permission to everyone on a bucket `foo`\n- Going to `/buckets/foo/collections/unknown` gives 404\n- Going to `/buckets/foo/collections/unknown/records` gives 503\n\nListing the records of an unknown collection should definitely give 404, except with the `default` bucket plugin.\n\nVery related to https://github.com/Kinto/kinto/issues/558\n\n", "before_files": [{"content": "import copy\n\nimport jsonschema\nfrom kinto.core import resource\nfrom kinto.core.errors import raise_invalid\nfrom jsonschema import exceptions as jsonschema_exceptions\nfrom pyramid.security import Authenticated\nfrom pyramid.settings import asbool\n\nfrom kinto.views import RelaxedUUID, object_exists_or_404\n\n\nclass RecordSchema(resource.ResourceSchema):\n    class Options:\n        preserve_unknown = True\n\n\n_parent_path = '/buckets/{{bucket_id}}/collections/{{collection_id}}'\n\n\n@resource.register(name='record',\n                   collection_path=_parent_path + '/records',\n                   record_path=_parent_path + '/records/{{id}}')\nclass Record(resource.ShareableResource):\n\n    mapping = RecordSchema()\n    schema_field = 'schema'\n\n    def __init__(self, *args, **kwargs):\n        super(Record, self).__init__(*args, **kwargs)\n\n        self.model.id_generator = RelaxedUUID()\n\n        # Check if already fetched before (in batch).\n        collections = self.request.bound_data.setdefault('collections', {})\n        collection_uri = self.get_parent_id(self.request)\n        if collection_uri not in collections:\n            # Unknown yet, fetch from storage.\n            collection_parent_id = '/buckets/%s' % self.bucket_id\n            collection = object_exists_or_404(self.request,\n                                              collection_id='collection',\n                                              parent_id=collection_parent_id,\n                                              object_id=self.collection_id)\n            collections[collection_uri] = collection\n\n        self._collection = collections[collection_uri]\n\n    def get_parent_id(self, request):\n        self.bucket_id = request.matchdict['bucket_id']\n        self.collection_id = request.matchdict['collection_id']\n        return '/buckets/%s/collections/%s' % (self.bucket_id,\n                                               self.collection_id)\n\n    def is_known_field(self, field_name):\n        \"\"\"Without schema, any field is considered as known.\"\"\"\n        return True\n\n    def process_record(self, new, old=None):\n        \"\"\"Validate records against collection schema, if any.\"\"\"\n        new = super(Record, self).process_record(new, old)\n\n        schema = self._collection.get('schema')\n        settings = self.request.registry.settings\n        schema_validation = 'experimental_collection_schema_validation'\n        if not schema or not asbool(settings.get(schema_validation)):\n            return new\n\n        collection_timestamp = self._collection[self.model.modified_field]\n\n        try:\n            stripped = copy.deepcopy(new)\n            stripped.pop(self.model.id_field, None)\n            stripped.pop(self.model.modified_field, None)\n            stripped.pop(self.model.permissions_field, None)\n            stripped.pop(self.schema_field, None)\n            jsonschema.validate(stripped, schema)\n        except jsonschema_exceptions.ValidationError as e:\n            try:\n                field = e.path.pop() if e.path else e.validator_value.pop()\n            except AttributeError:\n                field = None\n            raise_invalid(self.request, name=field, description=e.message)\n\n        new[self.schema_field] = collection_timestamp\n        return new\n\n    def collection_get(self):\n        result = super(Record, self).collection_get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def get(self):\n        result = super(Record, self).get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def _handle_cache_expires(self, response):\n        \"\"\"If the parent collection defines a ``cache_expires`` attribute,\n        then cache-control response headers are sent.\n\n        .. note::\n\n            Those headers are also sent if the\n            ``kinto.record_cache_expires_seconds`` setting is defined.\n        \"\"\"\n        is_anonymous = Authenticated not in self.request.effective_principals\n        if not is_anonymous:\n            return\n\n        cache_expires = self._collection.get('cache_expires')\n        if cache_expires is None:\n            by_bucket = '%s_record_cache_expires_seconds' % (self.bucket_id)\n            by_collection = '%s_%s_record_cache_expires_seconds' % (\n                self.bucket_id, self.collection_id)\n            settings = self.request.registry.settings\n            cache_expires = settings.get(by_collection,\n                                         settings.get(by_bucket))\n\n        if cache_expires is not None:\n            response.cache_expires(seconds=int(cache_expires))\n", "path": "kinto/views/records.py"}], "after_files": [{"content": "import copy\n\nimport jsonschema\nfrom kinto.core import resource\nfrom kinto.core.errors import raise_invalid\nfrom jsonschema import exceptions as jsonschema_exceptions\nfrom pyramid.security import Authenticated\nfrom pyramid.settings import asbool\n\nfrom kinto.views import RelaxedUUID, object_exists_or_404\n\n\nclass RecordSchema(resource.ResourceSchema):\n    class Options:\n        preserve_unknown = True\n\n\n_parent_path = '/buckets/{{bucket_id}}/collections/{{collection_id}}'\n\n\n@resource.register(name='record',\n                   collection_path=_parent_path + '/records',\n                   record_path=_parent_path + '/records/{{id}}')\nclass Record(resource.ShareableResource):\n\n    mapping = RecordSchema()\n    schema_field = 'schema'\n\n    def __init__(self, request, **kwargs):\n        # Before all, first check that the parent collection exists.\n        # Check if already fetched before (in batch).\n        collections = request.bound_data.setdefault('collections', {})\n        collection_uri = self.get_parent_id(request)\n        if collection_uri not in collections:\n            # Unknown yet, fetch from storage.\n            collection_parent_id = '/buckets/%s' % self.bucket_id\n            collection = object_exists_or_404(request,\n                                              collection_id='collection',\n                                              parent_id=collection_parent_id,\n                                              object_id=self.collection_id)\n            collections[collection_uri] = collection\n\n        super(Record, self).__init__(request, **kwargs)\n        self.model.id_generator = RelaxedUUID()\n        self._collection = collections[collection_uri]\n\n    def get_parent_id(self, request):\n        self.bucket_id = request.matchdict['bucket_id']\n        self.collection_id = request.matchdict['collection_id']\n        return '/buckets/%s/collections/%s' % (self.bucket_id,\n                                               self.collection_id)\n\n    def is_known_field(self, field_name):\n        \"\"\"Without schema, any field is considered as known.\"\"\"\n        return True\n\n    def process_record(self, new, old=None):\n        \"\"\"Validate records against collection schema, if any.\"\"\"\n        new = super(Record, self).process_record(new, old)\n\n        schema = self._collection.get('schema')\n        settings = self.request.registry.settings\n        schema_validation = 'experimental_collection_schema_validation'\n        if not schema or not asbool(settings.get(schema_validation)):\n            return new\n\n        collection_timestamp = self._collection[self.model.modified_field]\n\n        try:\n            stripped = copy.deepcopy(new)\n            stripped.pop(self.model.id_field, None)\n            stripped.pop(self.model.modified_field, None)\n            stripped.pop(self.model.permissions_field, None)\n            stripped.pop(self.schema_field, None)\n            jsonschema.validate(stripped, schema)\n        except jsonschema_exceptions.ValidationError as e:\n            try:\n                field = e.path.pop() if e.path else e.validator_value.pop()\n            except AttributeError:\n                field = None\n            raise_invalid(self.request, name=field, description=e.message)\n\n        new[self.schema_field] = collection_timestamp\n        return new\n\n    def collection_get(self):\n        result = super(Record, self).collection_get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def get(self):\n        result = super(Record, self).get()\n        self._handle_cache_expires(self.request.response)\n        return result\n\n    def _handle_cache_expires(self, response):\n        \"\"\"If the parent collection defines a ``cache_expires`` attribute,\n        then cache-control response headers are sent.\n\n        .. note::\n\n            Those headers are also sent if the\n            ``kinto.record_cache_expires_seconds`` setting is defined.\n        \"\"\"\n        is_anonymous = Authenticated not in self.request.effective_principals\n        if not is_anonymous:\n            return\n\n        cache_expires = self._collection.get('cache_expires')\n        if cache_expires is None:\n            by_bucket = '%s_record_cache_expires_seconds' % (self.bucket_id)\n            by_collection = '%s_%s_record_cache_expires_seconds' % (\n                self.bucket_id, self.collection_id)\n            settings = self.request.registry.settings\n            cache_expires = settings.get(by_collection,\n                                         settings.get(by_bucket))\n\n        if cache_expires is not None:\n            response.cache_expires(seconds=int(cache_expires))\n", "path": "kinto/views/records.py"}]}