Revert "Extend dynamicRef keyword"v4.5.1

It needs performance optimization. See python-jsonschema/jsonschema#941.

This reverts commit 12c791ee81baf27e54d18baf95b975bd48387dc6.

5 files changed, 34 insertions, 100 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 17c09da..7a19b9b 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -3,7 +3,6 @@ v4.5.0
 
 * Validator classes for each version now maintain references to the correct
   corresponding format checker (#905)
-* Support for ``$dynamicRef`` has been improved (#886)
 * Development has moved to a `GitHub organization
   <https://github.com/python-jsonschema/>`_.
   No functional behavior changes are expected from the change.
diff --git a/jsonschema/_utils.py b/jsonschema/_utils.py
index a4ab2ad..a2ad5a9 100644
--- a/jsonschema/_utils.py
+++ b/jsonschema/_utils.py
@@ -1,4 +1,3 @@
-from collections import deque
 from collections.abc import Mapping, MutableMapping, Sequence
 from urllib.parse import urlsplit
 import itertools
@@ -347,85 +346,3 @@ def find_evaluated_property_keys_by_schema(validator, instance, schema):
                 )
 
     return evaluated_keys
-
-
-def _schema_is_referenced(schema, parent_schema):
-    """
-    Checks if a schema is referenced by another schema
-    """
-    return (
-        "$id" in schema
-        and "$ref" in parent_schema
-        and parent_schema["$ref"] == schema["$id"]
-    )
-
-
-def _find_dynamic_anchor_extender(validator, scopes, fragment, schema):
-    """
-    Find a schema that extends the dynamic anchor
-    """
-    for url in scopes:
-        with validator.resolver.resolving(url) as parent_schema:
-            if _schema_is_referenced(schema, parent_schema):
-                return validator.resolver.resolve_fragment(
-                    parent_schema,
-                    fragment,
-                )
-
-
-def _find_dynamic_anchor_intermediate(validator, scopes, fragment):
-    """
-    Find a schema that extends the dynamic anchor by an intermediate schema
-    """
-    for url in scopes:
-        with validator.resolver.resolving(url) as schema:
-            if "$id" in schema:
-                for intermediate_url in scopes:
-                    with validator.resolver.resolving(
-                            intermediate_url) as intermediate_schema:
-                        for subschema in search_schema(
-                                intermediate_schema, match_keyword("$ref")):
-                            if _schema_is_referenced(subschema, schema):
-                                return _find_dynamic_anchor_extender(
-                                    validator,
-                                    scopes,
-                                    fragment,
-                                    subschema,
-                                )
-
-
-def dynamic_anchor_extender(validator, scopes, fragment, schema, subschema):
-    extender_schema = _find_dynamic_anchor_extender(
-        validator, scopes, fragment, schema,
-    )
-    if not extender_schema:
-        extender_schema = _find_dynamic_anchor_extender(
-            validator, scopes, fragment, subschema,
-        )
-    if not extender_schema:
-        extender_schema = _find_dynamic_anchor_intermediate(
-            validator, scopes, fragment,
-        )
-
-    return extender_schema
-
-
-def match_keyword(keyword):
-    def matcher(value):
-        if keyword in value:
-            yield value
-    return matcher
-
-
-def search_schema(schema, matcher):
-    """Breadth-first search routine."""
-    values = deque([schema])
-    while values:
-        value = values.pop()
-        if isinstance(value, list):
-            values.extendleft(value)
-            continue
-        if not isinstance(value, dict):
-            continue
-        yield from matcher(value)
-        values.extendleft(value.values())
diff --git a/jsonschema/_validators.py b/jsonschema/_validators.py
index 8caaa7e..9a07f5e 100644
--- a/jsonschema/_validators.py
+++ b/jsonschema/_validators.py
@@ -3,7 +3,6 @@ from urllib.parse import urldefrag, urljoin
 import re
 
 from jsonschema._utils import (
-    dynamic_anchor_extender,
     ensure_list,
     equal,
     extras_msg,
@@ -303,21 +302,14 @@ def ref(validator, ref, instance, schema):
 
 def dynamicRef(validator, dynamicRef, instance, schema):
     _, fragment = urldefrag(dynamicRef)
+
     for url in validator.resolver._scopes_stack:
         lookup_url = urljoin(url, dynamicRef)
         with validator.resolver.resolving(lookup_url) as subschema:
             if ("$dynamicAnchor" in subschema
                     and fragment == subschema["$dynamicAnchor"]):
-                scope_stack = list(validator.resolver._scopes_stack)
-                scope_stack.reverse()
-                extended_schema = dynamic_anchor_extender(
-                    validator, scope_stack, fragment, schema, subschema,
-                )
-                if extended_schema:
-                    yield from validator.descend(instance, extended_schema)
-                    break
-
                 yield from validator.descend(instance, subschema)
+                break
     else:
         with validator.resolver.resolving(dynamicRef) as subschema:
             yield from validator.descend(instance, subschema)
diff --git a/jsonschema/tests/test_jsonschema_test_suite.py b/jsonschema/tests/test_jsonschema_test_suite.py
index a656ab8..2d807b7 100644
--- a/jsonschema/tests/test_jsonschema_test_suite.py
+++ b/jsonschema/tests/test_jsonschema_test_suite.py
@@ -395,7 +395,15 @@ TestDraft202012 = DRAFT202012.to_unittest_testcase(
     skip=lambda test: (
         narrow_unicode_build(test)
         or skip(
-            message="These tests require an extension or the url resolver.",
+            message="dynamicRef support isn't working yet.",
+            subject="dynamicRef",
+        )(test)
+        or skip(
+            message="These tests depends on dynamicRef working.",
+            subject="defs",
+        )(test)
+        or skip(
+            message="These tests depends on dynamicRef working.",
             subject="anchor",
             case_description="same $anchor with different base uri",
         )(test)
diff --git a/jsonschema/validators.py b/jsonschema/validators.py
index ccf4e2c..5a0b8b9 100644
--- a/jsonschema/validators.py
+++ b/jsonschema/validators.py
@@ -3,6 +3,7 @@ Creation and extension of validators, with implementations for existing drafts.
 """
 from __future__ import annotations
 
+from collections import deque
 from collections.abc import Sequence
 from functools import lru_cache
 from urllib.parse import unquote, urldefrag, urljoin, urlsplit
@@ -805,7 +806,7 @@ class RefResolver(object):
     @lru_cache()  # noqa: B019
     def _get_subschemas_cache(self):
         cache = {key: [] for key in _SUBSCHEMAS_KEYWORDS}
-        for keyword, subschema in _utils.search_schema(
+        for keyword, subschema in _search_schema(
             self.referrer, _match_subschema_keywords,
         ):
             cache[keyword].append(subschema)
@@ -879,10 +880,7 @@ class RefResolver(object):
         else:
 
             def find(key):
-                yield from _utils.search_schema(
-                    document,
-                    _utils.match_keyword(key),
-                )
+                yield from _search_schema(document, _match_keyword(key))
 
         for keyword in ["$anchor", "$dynamicAnchor"]:
             for subschema in find(keyword):
@@ -968,12 +966,32 @@ class RefResolver(object):
 _SUBSCHEMAS_KEYWORDS = ("$id", "id", "$anchor", "$dynamicAnchor")
 
 
+def _match_keyword(keyword):
+
+    def matcher(value):
+        if keyword in value:
+            yield value
+
+    return matcher
+
+
 def _match_subschema_keywords(value):
     for keyword in _SUBSCHEMAS_KEYWORDS:
         if keyword in value:
             yield keyword, value
 
 
+def _search_schema(schema, matcher):
+    """Breadth-first search routine."""
+    values = deque([schema])
+    while values:
+        value = values.pop()
+        if not isinstance(value, dict):
+            continue
+        yield from matcher(value)
+        values.extendleft(value.values())
+
+
 def validate(instance, schema, cls=None, *args, **kwargs):
     """
     Validate an instance under the given schema.