Merge pull request #1355 from meejah/4087.cbor2-encoding

blacklist cbor2 version

setup.py

@@ -143,7 +143,8 @@ def read_version_py(infname):
     # 2.2.0 has a bug: https://github.com/pallets/werkzeug/issues/2465
     "werkzeug != 2.2.0",
     "treq",
-    "cbor2",
+    # 5.6.0 excluded because https://github.com/agronholm/cbor2/issues/208
+    "cbor2 != 5.6.0",
 
     # 0.4 adds the ability to pass in mmap() values which greatly reduces the
     # amount of copying involved.

src/allmydata/test/test_storage_http.py

@@ -41,6 +41,7 @@
 from werkzeug.exceptions import NotFound as WNotFound
 from testtools.matchers import Equals
 from zope.interface import implementer
+import cbor2
 
 from ..util.deferredutil import async_to_deferred
 from ..util.cputhreadpool import disable_thread_pool_for_test
@@ -1835,3 +1836,14 @@ def test_read_with_no_range(self, data_length):
         A read with no range returns the whole mutable.
         """
         return self._read_with_no_range_test(data_length)
+
+    def test_roundtrip_cbor2_encoding_issue(self):
+        """
+        Some versions of cbor2 (5.6.0) don't correctly encode bytestrings
+        bigger than 65535
+        """
+        for size in range(0, 65535*2, 17):
+            self.assertEqual(
+                size,
+                len(cbor2.loads(cbor2.dumps(b"\12" * size)))
+            )