diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 4bc29c8207..144cb9ffaa 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -53,10 +53,22 @@ jobs:
env:
PULL_REQUEST_NUMBER: ${{ github.event.number }}
+ lint-pydantic:
+ runs-on: ubuntu-latest
+ steps:
+ - uses: actions/checkout@v2
+ with:
+ ref: ${{ github.event.pull_request.head.sha }}
+ fetch-depth: 0
+ - uses: matrix-org/setup-python-poetry@v1
+ with:
+ extras: "all"
+ - run: poetry run scripts-dev/check_pydantic_models.py
+
# Dummy step to gate other tests on without repeating the whole list
linting-done:
if: ${{ !cancelled() }} # Run this even if prior jobs were skipped
- needs: [lint, lint-crlf, lint-newsfile, check-sampleconfig, check-schema-delta]
+ needs: [lint, lint-crlf, lint-newsfile, lint-pydantic, check-sampleconfig, check-schema-delta]
runs-on: ubuntu-latest
steps:
- run: "true"
diff --git a/changelog.d/13502.misc b/changelog.d/13502.misc
new file mode 100644
index 0000000000..ed6832996e
--- /dev/null
+++ b/changelog.d/13502.misc
@@ -0,0 +1 @@
+Add a linter script which will reject non-strict types in Pydantic models.
diff --git a/scripts-dev/check_pydantic_models.py b/scripts-dev/check_pydantic_models.py
new file mode 100755
index 0000000000..d0fb811bdb
--- /dev/null
+++ b/scripts-dev/check_pydantic_models.py
@@ -0,0 +1,425 @@
+#! /usr/bin/env python
+# Copyright 2022 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+A script which enforces that Synapse always uses strict types when defining a Pydantic
+model.
+
+Pydantic does not yet offer a strict mode, but it is planned for pydantic v2. See
+
+ https://github.com/pydantic/pydantic/issues/1098
+ https://pydantic-docs.helpmanual.io/blog/pydantic-v2/#strict-mode
+
+until then, this script is a best effort to stop us from introducing type coersion bugs
+(like the infamous stringy power levels fixed in room version 10).
+"""
+import argparse
+import contextlib
+import functools
+import importlib
+import logging
+import os
+import pkgutil
+import sys
+import textwrap
+import traceback
+import unittest.mock
+from contextlib import contextmanager
+from typing import Any, Callable, Dict, Generator, List, Set, Type, TypeVar
+
+from parameterized import parameterized
+from pydantic import BaseModel as PydanticBaseModel, conbytes, confloat, conint, constr
+from pydantic.typing import get_args
+from typing_extensions import ParamSpec
+
+logger = logging.getLogger(__name__)
+
+CONSTRAINED_TYPE_FACTORIES_WITH_STRICT_FLAG: List[Callable] = [
+ constr,
+ conbytes,
+ conint,
+ confloat,
+]
+
+TYPES_THAT_PYDANTIC_WILL_COERCE_TO = [
+ str,
+ bytes,
+ int,
+ float,
+ bool,
+]
+
+
+P = ParamSpec("P")
+R = TypeVar("R")
+
+
+class ModelCheckerException(Exception):
+ """Dummy exception. Allows us to detect unwanted types during a module import."""
+
+
+class MissingStrictInConstrainedTypeException(ModelCheckerException):
+ factory_name: str
+
+ def __init__(self, factory_name: str):
+ self.factory_name = factory_name
+
+
+class FieldHasUnwantedTypeException(ModelCheckerException):
+ message: str
+
+ def __init__(self, message: str):
+ self.message = message
+
+
+def make_wrapper(factory: Callable[P, R]) -> Callable[P, R]:
+ """We patch `constr` and friends with wrappers that enforce strict=True."""
+
+ @functools.wraps(factory)
+ def wrapper(*args: P.args, **kwargs: P.kwargs) -> R:
+ # type-ignore: should be redundant once we can use https://github.com/python/mypy/pull/12668
+ if "strict" not in kwargs: # type: ignore[attr-defined]
+ raise MissingStrictInConstrainedTypeException(factory.__name__)
+ if not kwargs["strict"]: # type: ignore[index]
+ raise MissingStrictInConstrainedTypeException(factory.__name__)
+ return factory(*args, **kwargs)
+
+ return wrapper
+
+
+def field_type_unwanted(type_: Any) -> bool:
+ """Very rough attempt to detect if a type is unwanted as a Pydantic annotation.
+
+ At present, we exclude types which will coerce, or any generic type involving types
+ which will coerce."""
+ logger.debug("Is %s unwanted?")
+ if type_ in TYPES_THAT_PYDANTIC_WILL_COERCE_TO:
+ logger.debug("yes")
+ return True
+ logger.debug("Maybe. Subargs are %s", get_args(type_))
+ rv = any(field_type_unwanted(t) for t in get_args(type_))
+ logger.debug("Conclusion: %s %s unwanted", type_, "is" if rv else "is not")
+ return rv
+
+
+class PatchedBaseModel(PydanticBaseModel):
+ """A patched version of BaseModel that inspects fields after models are defined.
+
+ We complain loudly if we see an unwanted type.
+
+ Beware: ModelField.type_ is presumably private; this is likely to be very brittle.
+ """
+
+ @classmethod
+ def __init_subclass__(cls: Type[PydanticBaseModel], **kwargs: object):
+ for field in cls.__fields__.values():
+ # Note that field.type_ and field.outer_type are computed based on the
+ # annotation type, see pydantic.fields.ModelField._type_analysis
+ if field_type_unwanted(field.outer_type_):
+ # TODO: this only reports the first bad field. Can we find all bad ones
+ # and report them all?
+ raise FieldHasUnwantedTypeException(
+ f"{cls.__module__}.{cls.__qualname__} has field '{field.name}' "
+ f"with unwanted type `{field.outer_type_}`"
+ )
+
+
+@contextmanager
+def monkeypatch_pydantic() -> Generator[None, None, None]:
+ """Patch pydantic with our snooping versions of BaseModel and the con* functions.
+
+ If the snooping functions see something they don't like, they'll raise a
+ ModelCheckingException instance.
+ """
+ with contextlib.ExitStack() as patches:
+ # Most Synapse code ought to import the patched objects directly from
+ # `pydantic`. But we also patch their containing modules `pydantic.main` and
+ # `pydantic.types` for completeness.
+ patch_basemodel1 = unittest.mock.patch(
+ "pydantic.BaseModel", new=PatchedBaseModel
+ )
+ patch_basemodel2 = unittest.mock.patch(
+ "pydantic.main.BaseModel", new=PatchedBaseModel
+ )
+ patches.enter_context(patch_basemodel1)
+ patches.enter_context(patch_basemodel2)
+ for factory in CONSTRAINED_TYPE_FACTORIES_WITH_STRICT_FLAG:
+ wrapper: Callable = make_wrapper(factory)
+ patch1 = unittest.mock.patch(f"pydantic.{factory.__name__}", new=wrapper)
+ patch2 = unittest.mock.patch(
+ f"pydantic.types.{factory.__name__}", new=wrapper
+ )
+ patches.enter_context(patch1)
+ patches.enter_context(patch2)
+ yield
+
+
+def format_model_checker_exception(e: ModelCheckerException) -> str:
+ """Work out which line of code caused e. Format the line in a human-friendly way."""
+ # TODO. FieldHasUnwantedTypeException gives better error messages. Can we ditch the
+ # patches of constr() etc, and instead inspect fields to look for ConstrainedStr
+ # with strict=False? There is some difficulty with the inheritance hierarchy
+ # because StrictStr < ConstrainedStr < str.
+ if isinstance(e, FieldHasUnwantedTypeException):
+ return e.message
+ elif isinstance(e, MissingStrictInConstrainedTypeException):
+ frame_summary = traceback.extract_tb(e.__traceback__)[-2]
+ return (
+ f"Missing `strict=True` from {e.factory_name}() call \n"
+ + traceback.format_list([frame_summary])[0].lstrip()
+ )
+ else:
+ raise ValueError(f"Unknown exception {e}") from e
+
+
+def lint() -> int:
+ """Try to import all of Synapse and see if we spot any Pydantic type coercions.
+
+ Print any problems, then return a status code suitable for sys.exit."""
+ failures = do_lint()
+ if failures:
+ print(f"Found {len(failures)} problem(s)")
+ for failure in sorted(failures):
+ print(failure)
+ return os.EX_DATAERR if failures else os.EX_OK
+
+
+def do_lint() -> Set[str]:
+ """Try to import all of Synapse and see if we spot any Pydantic type coercions."""
+ failures = set()
+
+ with monkeypatch_pydantic():
+ logger.debug("Importing synapse")
+ try:
+ # TODO: make "synapse" an argument so we can target this script at
+ # a subpackage
+ module = importlib.import_module("synapse")
+ except ModelCheckerException as e:
+ logger.warning("Bad annotation found when importing synapse")
+ failures.add(format_model_checker_exception(e))
+ return failures
+
+ try:
+ logger.debug("Fetching subpackages")
+ module_infos = list(
+ pkgutil.walk_packages(module.__path__, f"{module.__name__}.")
+ )
+ except ModelCheckerException as e:
+ logger.warning("Bad annotation found when looking for modules to import")
+ failures.add(format_model_checker_exception(e))
+ return failures
+
+ for module_info in module_infos:
+ logger.debug("Importing %s", module_info.name)
+ try:
+ importlib.import_module(module_info.name)
+ except ModelCheckerException as e:
+ logger.warning(
+ f"Bad annotation found when importing {module_info.name}"
+ )
+ failures.add(format_model_checker_exception(e))
+
+ return failures
+
+
+def run_test_snippet(source: str) -> None:
+ """Exec a snippet of source code in an isolated environment."""
+ # To emulate `source` being called at the top level of the module,
+ # the globals and locals we provide apparently have to be the same mapping.
+ #
+ # > Remember that at the module level, globals and locals are the same dictionary.
+ # > If exec gets two separate objects as globals and locals, the code will be
+ # > executed as if it were embedded in a class definition.
+ globals_: Dict[str, object]
+ locals_: Dict[str, object]
+ globals_ = locals_ = {}
+ exec(textwrap.dedent(source), globals_, locals_)
+
+
+class TestConstrainedTypesPatch(unittest.TestCase):
+ def test_expression_without_strict_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic import constr
+ constr()
+ """
+ )
+
+ def test_called_as_module_attribute_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ import pydantic
+ pydantic.constr()
+ """
+ )
+
+ def test_wildcard_import_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic import *
+ constr()
+ """
+ )
+
+ def test_alternative_import_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic.types import constr
+ constr()
+ """
+ )
+
+ def test_alternative_import_attribute_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ import pydantic.types
+ pydantic.types.constr()
+ """
+ )
+
+ def test_kwarg_but_no_strict_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic import constr
+ constr(min_length=10)
+ """
+ )
+
+ def test_kwarg_strict_False_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic import constr
+ constr(strict=False)
+ """
+ )
+
+ def test_kwarg_strict_True_doesnt_raise(self) -> None:
+ with monkeypatch_pydantic():
+ run_test_snippet(
+ """
+ from pydantic import constr
+ constr(strict=True)
+ """
+ )
+
+ def test_annotation_without_strict_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic import constr
+ x: constr()
+ """
+ )
+
+ def test_field_annotation_without_strict_raises(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic import BaseModel, conint
+ class C:
+ x: conint()
+ """
+ )
+
+
+class TestFieldTypeInspection(unittest.TestCase):
+ @parameterized.expand(
+ [
+ ("str",),
+ ("bytes"),
+ ("int",),
+ ("float",),
+ ("bool"),
+ ("Optional[str]",),
+ ("Union[None, str]",),
+ ("List[str]",),
+ ("List[List[str]]",),
+ ("Dict[StrictStr, str]",),
+ ("Dict[str, StrictStr]",),
+ ("TypedDict('D', x=int)",),
+ ]
+ )
+ def test_field_holding_unwanted_type_raises(self, annotation: str) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ f"""
+ from typing import *
+ from pydantic import *
+ class C(BaseModel):
+ f: {annotation}
+ """
+ )
+
+ @parameterized.expand(
+ [
+ ("StrictStr",),
+ ("StrictBytes"),
+ ("StrictInt",),
+ ("StrictFloat",),
+ ("StrictBool"),
+ ("constr(strict=True, min_length=10)",),
+ ("Optional[StrictStr]",),
+ ("Union[None, StrictStr]",),
+ ("List[StrictStr]",),
+ ("List[List[StrictStr]]",),
+ ("Dict[StrictStr, StrictStr]",),
+ ("TypedDict('D', x=StrictInt)",),
+ ]
+ )
+ def test_field_holding_accepted_type_doesnt_raise(self, annotation: str) -> None:
+ with monkeypatch_pydantic():
+ run_test_snippet(
+ f"""
+ from typing import *
+ from pydantic import *
+ class C(BaseModel):
+ f: {annotation}
+ """
+ )
+
+ def test_field_holding_str_raises_with_alternative_import(self) -> None:
+ with monkeypatch_pydantic(), self.assertRaises(ModelCheckerException):
+ run_test_snippet(
+ """
+ from pydantic.main import BaseModel
+ class C(BaseModel):
+ f: str
+ """
+ )
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("mode", choices=["lint", "test"], default="lint", nargs="?")
+parser.add_argument("-v", "--verbose", action="store_true")
+
+
+if __name__ == "__main__":
+ args = parser.parse_args(sys.argv[1:])
+ logging.basicConfig(
+ format="%(asctime)s %(name)s:%(lineno)d %(levelname)s %(message)s",
+ level=logging.DEBUG if args.verbose else logging.INFO,
+ )
+ # suppress logs we don't care about
+ logging.getLogger("xmlschema").setLevel(logging.WARNING)
+ if args.mode == "lint":
+ sys.exit(lint())
+ elif args.mode == "test":
+ unittest.main(argv=sys.argv[:1])
diff --git a/scripts-dev/lint.sh b/scripts-dev/lint.sh
index 377348b107..bf900645b1 100755
--- a/scripts-dev/lint.sh
+++ b/scripts-dev/lint.sh
@@ -106,4 +106,5 @@ isort "${files[@]}"
python3 -m black "${files[@]}"
./scripts-dev/config-lint.sh
flake8 "${files[@]}"
+./scripts-dev/check_pydantic_models.py lint
mypy
|
