Deprecate Validator.resolver.

It will imminently be replaced by referencing.Registry-based
resolution.

4 files changed, 39 insertions, 6 deletions

diff --git a/jsonschema/protocols.py b/jsonschema/protocols.py
index c9c71dc..eb67444 100644
--- a/jsonschema/protocols.py
+++ b/jsonschema/protocols.py
@@ -65,6 +65,11 @@ class Validator(Protocol):
             a resolver that will be used to resolve :kw:`$ref`
             properties (JSON references). If unprovided, one will be created.
 
+            .. deprecated:: v4.18.0
+
+                `RefResolver` has been deprecated in favor of `referencing`,
+                and with it, this argument.
+
         format_checker:
 
             if provided, a checker which will be used to assert about
@@ -108,7 +113,6 @@ class Validator(Protocol):
     def __init__(
         self,
         schema: Mapping | bool,
-        resolver: jsonschema.validators._RefResolver | None = None,
         format_checker: jsonschema.FormatChecker | None = None,
     ) -> None:
         ...
diff --git a/jsonschema/tests/test_deprecations.py b/jsonschema/tests/test_deprecations.py
index 898a792..d21065f 100644
--- a/jsonschema/tests/test_deprecations.py
+++ b/jsonschema/tests/test_deprecations.py
@@ -125,6 +125,22 @@ class TestDeprecations(TestCase):
             ),
         )
 
+    def test_Validator_resolver(self):
+        """
+        As of v4.18.0, accessing Validator.resolver is deprecated.
+        """
+
+        validator = validators.Draft7Validator({})
+        with self.assertWarns(DeprecationWarning) as w:
+            self.assertIsInstance(validator.resolver, validators._RefResolver)
+
+        self.assertEqual(w.filename, __file__)
+        self.assertTrue(
+            str(w.warning).startswith(
+                "Accessing Draft7Validator.resolver is ",
+            ),
+        )
+
     def test_Validator_subclassing(self):
         """
         As of v4.12.0, subclassing a validator class produces an explicit
diff --git a/jsonschema/tests/test_validators.py b/jsonschema/tests/test_validators.py
index f94b69b..a76b247 100644
--- a/jsonschema/tests/test_validators.py
+++ b/jsonschema/tests/test_validators.py
@@ -1735,10 +1735,9 @@ class ValidatorTestMixin(MetaSchemaTestsMixin, object):
                 validator.validate(instance)
 
     def test_it_creates_a_ref_resolver_if_not_provided(self):
-        self.assertIsInstance(
-            self.Validator({}).resolver,
-            validators._RefResolver,
-        )
+        with self.assertWarns(DeprecationWarning):
+            resolver = self.Validator({}).resolver
+        self.assertIsInstance(resolver, validators._RefResolver)
 
     def test_it_upconverts_from_deprecated_RefResolvers(self):
         ref, schema = "someCoolRef", {"type": "integer"}
diff --git a/jsonschema/validators.py b/jsonschema/validators.py
index be5ff18..8abec84 100644
--- a/jsonschema/validators.py
+++ b/jsonschema/validators.py
@@ -212,6 +212,18 @@ def create(
 
         @property
         def resolver(self):
+            warnings.warn(
+                (
+                    f"Accessing {self.__class__.__name__}.resolver is "
+                    "deprecated as of v4.18.0, in favor of the "
+                    "https://github.com/python-jsonschema/referencing "
+                    "library, which provides more compliant referencing "
+                    "behavior as well as more flexible APIs for "
+                    "customization."
+                ),
+                DeprecationWarning,
+                stacklevel=2,
+            )
             if self._resolver is None:
                 self._resolver = _RefResolver.from_schema(
                     self.schema,
@@ -265,7 +277,9 @@ def create(
                 return
 
             # Temporarily needed to eagerly create a resolver...
-            self.resolver
+            with warnings.catch_warnings():
+                warnings.simplefilter("ignore")
+                self.resolver
             scope = id_of(_schema)
             if scope:
                 self.resolver.push_scope(scope)