From 801a4cecc7a0cf3653db8e054fee5e800cd471e5 Mon Sep 17 00:00:00 2001
From: Julian Berman <Julian@GrayVines.com>
Date: Tue, 18 Jul 2023 10:23:04 +0200
Subject: [PATCH] Improve the hashability of referencing exceptions when they
 contain hashable data.

Closes: #1126
---
 CHANGELOG.rst                         |  5 +++++
 jsonschema/exceptions.py              |  3 +++
 jsonschema/tests/test_deprecations.py | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index be6d73b71..84df7c661 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -1,3 +1,8 @@
+v4.18.4
+=======
+
+* Improve the hashability of wrapped referencing exceptions when they contain hashable data.
+
 v4.18.3
 =======
 
diff --git a/jsonschema/exceptions.py b/jsonschema/exceptions.py
index 80679c1b5..80281057e 100644
--- a/jsonschema/exceptions.py
+++ b/jsonschema/exceptions.py
@@ -230,6 +230,9 @@ def __eq__(self, other):
     def __getattr__(self, attr):
         return getattr(self._wrapped, attr)
 
+    def __hash__(self):
+        return hash(self._wrapped)
+
     def __repr__(self):
         return f"<WrappedReferencingError {self._wrapped!r}>"
 
diff --git a/jsonschema/tests/test_deprecations.py b/jsonschema/tests/test_deprecations.py
index 7c287427b..85927e695 100644
--- a/jsonschema/tests/test_deprecations.py
+++ b/jsonschema/tests/test_deprecations.py
@@ -211,6 +211,24 @@ def test_catching_Unresolvable_via_RefResolutionError(self):
             (u.exception, "Unresolvable: urn:nothing")
         )
 
+    def test_WrappedReferencingError_hashability(self):
+        """
+        Ensure the wrapped referencing errors are hashable when possible.
+        """
+        with self.assertWarns(DeprecationWarning):
+            from jsonschema import RefResolutionError
+
+        validator = validators.Draft202012Validator({"$ref": "urn:nothing"})
+
+        with self.assertRaises(referencing.exceptions.Unresolvable) as u:
+            validator.validate(12)
+
+        with self.assertRaises(RefResolutionError) as e:
+            validator.validate(12)
+
+        self.assertIn(e.exception, {u.exception})
+        self.assertIn(u.exception, {e.exception})
+
     def test_Validator_subclassing(self):
         """
         As of v4.12.0, subclassing a validator class produces an explicit