Anchor $ to end of string in patternProperties regexes

CHANGELOG.txt

@@ -1,3 +1,7 @@
+=== UNRELEASED
+
+* Fixed `$` in `patternProperties` matching before a trailing newline, which also made a `pattern` with the same regex accept a trailing newline
+
 === 2.22.3 (2026-11-01)
 
 * Fixed property names with `{` or `}` being evaluated as format string in error messages

fastjsonschema/draft04.py

@@ -596,7 +596,8 @@ def generate_pattern_properties(self):
             if pattern_prop_definition == {}:
                 return
             for pattern, definition in pattern_prop_definition.items():
-                self._compile_regexps[pattern] = re.compile(pattern)
+                end_of_string_fixed_pattern = DOLLAR_FINDER.sub(r'\\Z', pattern)
+                self._compile_regexps[pattern] = re.compile(end_of_string_fixed_pattern)
             with self.l('for {variable}_key, {variable}_val in {variable}.items():'):
                 for pattern, definition in self._definition['patternProperties'].items():
                     with self.l('if REGEX_PATTERNS[{}].search({variable}_key):', repr(pattern)):

tests/test_pattern_properties.py

@@ -2,6 +2,8 @@
 
 import pytest
 
+from fastjsonschema import JsonSchemaValueException
+
 
 def test_dont_override_variable_names(asserter):
     value = {
@@ -76,3 +78,30 @@ def test_empty_pattern(asserter):
         'type': 'object',
         'patternProperties': {}
     }, value, value)
+
+
+@pytest.mark.parametrize('value, expected', [
+    ({'abc': 1}, {'abc': 1}),
+    ({'abc\n': 1}, JsonSchemaValueException('data must not contain {\'abc\\n\'} properties', value='{data}', name='data', definition='{definition}', rule='additionalProperties')),
+])
+def test_pattern_dollar_does_not_match_trailing_newline(asserter, value, expected):
+    asserter({
+        'type': 'object',
+        'patternProperties': {
+            '^[a-z]+$': {},
+        },
+        'additionalProperties': False,
+    }, value, expected)
+
+
+@pytest.mark.parametrize('value, expected', [
+    ('abc', 'abc'),
+    ('abc\n', JsonSchemaValueException('data must match pattern ^[a-z]+$', value='{data}', name='data', definition='{definition}', rule='pattern')),
+])
+def test_pattern_shared_with_pattern_properties(asserter, value, expected):
+    asserter({
+        'pattern': '^[a-z]+$',
+        'patternProperties': {
+            '^[a-z]+$': {},
+        },
+    }, value, expected)