Use JS meaning of ^abc$

Author: Zac-HD

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+#### 0.22.0 - 2021-12-15
+- never generate trailing newlines for regex patterns ending in `$`
+  (allowed by Python, but not by JSON Schema)
+
 #### 0.21.0 - 2021-10-03
 - reduced filtering for object keys (#88)
 - updated to `jsonschema >= 4.0.0` (#89);

setup.py

@@ -31,7 +31,7 @@ def local_file(name: str) -> str:
     license="MPL 2.0",
     description="Generate test data from JSON schemata with Hypothesis",
     zip_safe=False,
-    install_requires=["hypothesis>=5.3.0", "jsonschema>=4.0.0"],
+    install_requires=["hypothesis>=6.31.6", "jsonschema>=4.0.0"],
     python_requires=">=3.7",
     classifiers=[
         "Development Status :: 4 - Beta",

src/hypothesis_jsonschema/__init__.py

@@ -3,7 +3,7 @@
 The only public API is `from_schema`; check the docstring for details.
 """
 
-__version__ = "0.21.0"
+__version__ = "0.22.0"
 __all__ = ["from_schema"]
 
 from ._from_schema import from_schema

src/hypothesis_jsonschema/_from_schema.py

@@ -7,12 +7,14 @@
 import warnings
 from fractions import Fraction
 from functools import partial
+from inspect import signature
 from typing import Any, Callable, Dict, List, NoReturn, Optional, Set, Union
 
 import jsonschema
 from hypothesis import assume, provisional as prov, strategies as st
 from hypothesis.errors import HypothesisWarning, InvalidArgument
 from hypothesis.internal.conjecture import utils as cu
+from hypothesis.strategies._internal.regex import regex_strategy
 
 from ._canonicalise import (
     FALSEY,
@@ -41,6 +43,17 @@
 )
 _FORMATS_TOKEN = object()
 
+from_js_regex: Callable[[str], st.SearchStrategy[str]] = st.from_regex
+if len(signature(regex_strategy).parameters) == 3:  # pragma: no branch
+    # On Hypothesis >= 6.31.6, we can use this to get the ECMA semantics of "$".
+    # Conditionally-defined so that we degrade relatively gracefully if you update
+    # Hypothesis but not hypothesis-jsonschema once we have a more general fix.
+
+    def from_js_regex(pattern: str) -> st.SearchStrategy[str]:
+        return regex_strategy(
+            pattern, fullmatch=False, _temp_jsonschema_hack_no_end_newline=True
+        )
+
 
 def merged_as_strategies(
     schemas: List[Schema], custom_formats: Optional[Dict[str, st.SearchStrategy[str]]]
@@ -429,7 +442,7 @@ def string_schema(
     elif "pattern" in schema:
         try:
             re.compile(schema["pattern"])
-            strategy = st.from_regex(schema["pattern"])
+            strategy = from_js_regex(schema["pattern"])
         except re.error as err:
             # Patterns that are invalid in Python, or just malformed
             _warn_invalid_regex(schema["pattern"], err)
@@ -585,7 +598,7 @@ def object_schema(
         if additional_allowed
         else st.nothing(),
         st.sampled_from(known_optional_names) if known_optional_names else st.nothing(),
-        st.one_of([st.from_regex(p).filter(valid_name) for p in sorted(patterns)]),
+        st.one_of([from_js_regex(p).filter(valid_name) for p in sorted(patterns)]),
     )
     all_names_strategy = st.one_of([s for s in name_strats if not s.is_empty])
 

tests/test_from_schema.py

@@ -535,3 +535,8 @@ def test_can_generate_empty_list_with_max_size_and_no_allowed_items(val):
     )
     def test_can_generate_list_with_max_size_and_no_allowed_additional_items(val):
         assert val == [1, 2, 3]
+
+
+@given(string=from_schema({"type": "string", "pattern": "^[a-z]+$"}))
+def test_does_not_generate_trailing_newline_from_dollar_pattern(string):
+    assert not string.endswith("\n")