Pinned trio to < 0.22 on AnyIO 3.x

The new MultiError is incompatible with AnyIO's ExceptionGroup class.

Author: agronholm

docs/versionhistory.rst

@@ -3,6 +3,12 @@ Version history
 
 This library adheres to `Semantic Versioning 2.0 <http://semver.org/>`_.
 
+**3.6.2**
+
+- Pinned Trio to < 0.22 to avoid incompatibility with AnyIO's ``ExceptionGroup`` class
+  causing ``AttributeError: 'NonBaseMultiError' object has no attribute '_exceptions'``
+  (AnyIO 4 is unaffected)
+
 **3.6.1**
 
 - Fixed exception handler in the asyncio test runner not properly handling a context

setup.cfg

@@ -52,7 +52,7 @@ test =
     trustme
     uvloop < 0.15; python_version < '3.7' and (platform_python_implementation == 'CPython' and platform_system != 'Windows')
     uvloop >= 0.15; python_version >= '3.7' and (platform_python_implementation == 'CPython' and platform_system != 'Windows')
-trio = trio >= 0.16
+trio = trio >= 0.16, < 0.22
 doc =
     packaging
     sphinx_rtd_theme