prompt: We are currently solving the following issue within our repository. Here is the issue text:
  --- BEGIN ISSUE ---
  Downloading store in a zip file with no revision lacks revision headers
  not sure if this is a dupe or related to other PO-headers bugs - but it seems like stores with no unit revision dont get headers - this causes re-uploading to fail
  
  --- END ISSUE ---
  
  Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
  --- BEGIN FILES ---
  Path: `pootle/apps/pootle_store/store/serialize.py`
  Content:
  ```
  1 # -*- coding: utf-8 -*-
  2 #
  3 # Copyright (C) Pootle contributors.
  4 #
  5 # This file is a part of the Pootle project. It is distributed under the GPL3
  6 # or later license. See the LICENSE file for a copy of the license and the
  7 # AUTHORS file for copyright and authorship information.
  8 
  9 from django.core.cache import caches
  10 from django.utils.functional import cached_property
  11 
  12 from pootle.core.delegate import config, serializers
  13 
  14 
  15 class StoreSerialization(object):
  16     """Calls configured deserializers for Store"""
  17 
  18     def __init__(self, store):
  19         self.store = store
  20 
  21     @property
  22     def project_serializers(self):
  23         project = self.store.translation_project.project
  24         return (
  25             config.get(
  26                 project.__class__,
  27                 instance=project,
  28                 key="pootle.core.serializers")
  29             or [])
  30 
  31     @property
  32     def pootle_path(self):
  33         return self.store.pootle_path
  34 
  35     @cached_property
  36     def max_unit_revision(self):
  37         return self.store.data.max_unit_revision
  38 
  39     @cached_property
  40     def serializers(self):
  41         available_serializers = serializers.gather(
  42             self.store.translation_project.project.__class__)
  43         found_serializers = []
  44         for serializer in self.project_serializers:
  45             found_serializers.append(available_serializers[serializer])
  46         return found_serializers
  47 
  48     def tostring(self):
  49         store = self.store.syncer.convert()
  50         if hasattr(store, "updateheader"):
  51             # FIXME We need those headers on import
  52             # However some formats just don't support setting metadata
  53             store.updateheader(add=True, X_Pootle_Path=self.pootle_path)
  54             store.updateheader(add=True, X_Pootle_Revision=self.max_unit_revision)
  55         return str(store)
  56 
  57     def pipeline(self, data):
  58         if not self.serializers:
  59             return data
  60         for serializer in self.serializers:
  61             data = serializer(self.store, data).output
  62         return data
  63 
  64     def serialize(self):
  65         cache = caches["exports"]
  66         ret = cache.get(
  67             self.pootle_path,
  68             version=self.max_unit_revision)
  69         if not ret:
  70             ret = self.pipeline(self.tostring())
  71             cache.set(
  72                 self.pootle_path,
  73                 ret,
  74                 version=self.max_unit_revision)
  75         return ret
  76
  ```
  --- 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/pootle/apps/pootle_store/store/serialize.py b/pootle/apps/pootle_store/store/serialize.py
  --- a/pootle/apps/pootle_store/store/serialize.py
  +++ b/pootle/apps/pootle_store/store/serialize.py
  @@ -50,8 +50,9 @@
           if hasattr(store, "updateheader"):
               # FIXME We need those headers on import
               # However some formats just don't support setting metadata
  +            max_unit_revision = self.max_unit_revision or 0
               store.updateheader(add=True, X_Pootle_Path=self.pootle_path)
  -            store.updateheader(add=True, X_Pootle_Revision=self.max_unit_revision)
  +            store.updateheader(add=True, X_Pootle_Revision=max_unit_revision)
           return str(store)
   
       def pipeline(self, data):
  
verification_info: {"golden_diff": "diff --git a/pootle/apps/pootle_store/store/serialize.py b/pootle/apps/pootle_store/store/serialize.py\n--- a/pootle/apps/pootle_store/store/serialize.py\n+++ b/pootle/apps/pootle_store/store/serialize.py\n@@ -50,8 +50,9 @@\n         if hasattr(store, \"updateheader\"):\n             # FIXME We need those headers on import\n             # However some formats just don't support setting metadata\n+            max_unit_revision = self.max_unit_revision or 0\n             store.updateheader(add=True, X_Pootle_Path=self.pootle_path)\n-            store.updateheader(add=True, X_Pootle_Revision=self.max_unit_revision)\n+            store.updateheader(add=True, X_Pootle_Revision=max_unit_revision)\n         return str(store)\n \n     def pipeline(self, data):\n", "issue": "Downloading store in a zip file with no revision lacks revision headers\nnot sure if this is a dupe or related to other PO-headers bugs - but it seems like stores with no unit revision dont get headers - this causes re-uploading to fail\n", "before_files": [{"content": "# -*- coding: utf-8 -*-\n#\n# Copyright (C) Pootle contributors.\n#\n# This file is a part of the Pootle project. It is distributed under the GPL3\n# or later license. See the LICENSE file for a copy of the license and the\n# AUTHORS file for copyright and authorship information.\n\nfrom django.core.cache import caches\nfrom django.utils.functional import cached_property\n\nfrom pootle.core.delegate import config, serializers\n\n\nclass StoreSerialization(object):\n    \"\"\"Calls configured deserializers for Store\"\"\"\n\n    def __init__(self, store):\n        self.store = store\n\n    @property\n    def project_serializers(self):\n        project = self.store.translation_project.project\n        return (\n            config.get(\n                project.__class__,\n                instance=project,\n                key=\"pootle.core.serializers\")\n            or [])\n\n    @property\n    def pootle_path(self):\n        return self.store.pootle_path\n\n    @cached_property\n    def max_unit_revision(self):\n        return self.store.data.max_unit_revision\n\n    @cached_property\n    def serializers(self):\n        available_serializers = serializers.gather(\n            self.store.translation_project.project.__class__)\n        found_serializers = []\n        for serializer in self.project_serializers:\n            found_serializers.append(available_serializers[serializer])\n        return found_serializers\n\n    def tostring(self):\n        store = self.store.syncer.convert()\n        if hasattr(store, \"updateheader\"):\n            # FIXME We need those headers on import\n            # However some formats just don't support setting metadata\n            store.updateheader(add=True, X_Pootle_Path=self.pootle_path)\n            store.updateheader(add=True, X_Pootle_Revision=self.max_unit_revision)\n        return str(store)\n\n    def pipeline(self, data):\n        if not self.serializers:\n            return data\n        for serializer in self.serializers:\n            data = serializer(self.store, data).output\n        return data\n\n    def serialize(self):\n        cache = caches[\"exports\"]\n        ret = cache.get(\n            self.pootle_path,\n            version=self.max_unit_revision)\n        if not ret:\n            ret = self.pipeline(self.tostring())\n            cache.set(\n                self.pootle_path,\n                ret,\n                version=self.max_unit_revision)\n        return ret\n", "path": "pootle/apps/pootle_store/store/serialize.py"}], "after_files": [{"content": "# -*- coding: utf-8 -*-\n#\n# Copyright (C) Pootle contributors.\n#\n# This file is a part of the Pootle project. It is distributed under the GPL3\n# or later license. See the LICENSE file for a copy of the license and the\n# AUTHORS file for copyright and authorship information.\n\nfrom django.core.cache import caches\nfrom django.utils.functional import cached_property\n\nfrom pootle.core.delegate import config, serializers\n\n\nclass StoreSerialization(object):\n    \"\"\"Calls configured deserializers for Store\"\"\"\n\n    def __init__(self, store):\n        self.store = store\n\n    @property\n    def project_serializers(self):\n        project = self.store.translation_project.project\n        return (\n            config.get(\n                project.__class__,\n                instance=project,\n                key=\"pootle.core.serializers\")\n            or [])\n\n    @property\n    def pootle_path(self):\n        return self.store.pootle_path\n\n    @cached_property\n    def max_unit_revision(self):\n        return self.store.data.max_unit_revision\n\n    @cached_property\n    def serializers(self):\n        available_serializers = serializers.gather(\n            self.store.translation_project.project.__class__)\n        found_serializers = []\n        for serializer in self.project_serializers:\n            found_serializers.append(available_serializers[serializer])\n        return found_serializers\n\n    def tostring(self):\n        store = self.store.syncer.convert()\n        if hasattr(store, \"updateheader\"):\n            # FIXME We need those headers on import\n            # However some formats just don't support setting metadata\n            max_unit_revision = self.max_unit_revision or 0\n            store.updateheader(add=True, X_Pootle_Path=self.pootle_path)\n            store.updateheader(add=True, X_Pootle_Revision=max_unit_revision)\n        return str(store)\n\n    def pipeline(self, data):\n        if not self.serializers:\n            return data\n        for serializer in self.serializers:\n            data = serializer(self.store, data).output\n        return data\n\n    def serialize(self):\n        cache = caches[\"exports\"]\n        ret = cache.get(\n            self.pootle_path,\n            version=self.max_unit_revision)\n        if not ret:\n            ret = self.pipeline(self.tostring())\n            cache.set(\n                self.pootle_path,\n                ret,\n                version=self.max_unit_revision)\n        return ret\n", "path": "pootle/apps/pootle_store/store/serialize.py"}]}