Add python-implemented ExceptionGroup

RustPython · youknowone · Apr 22, 2024 · Apr 22, 2024 · Apr 25, 2024 · Apr 25, 2024
commit 1815c43d7c191be63b0fa19a4f75ae3fa4fdb529
diff --git a/Lib/test/test_baseexception.py b/Lib/test/test_baseexception.py
@@ -18,8 +18,6 @@ def verify_instance_interface(self, ins):
                     "%s missing %s attribute" %
                         (ins.__class__.__name__, attr))
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_inheritance(self):
         # Make sure the inheritance hierarchy matches the documentation
         exc_set = set()

diff --git a/src/interpreter.rs b/src/interpreter.rs
@@ -18,6 +18,7 @@ pub type InitHook = Box<dyn FnOnce(&mut VirtualMachine)>;
 /// let mut settings = Settings::default();
 /// settings.debug = true;
 /// // You may want to add paths to `rustpython_vm::Settings::path_list` to allow import python libraries.
+/// settings.path_list.push("Lib".to_owned());  // add standard library directory
 /// settings.path_list.push("".to_owned());  // add current working directory
 /// let interpreter = rustpython::InterpreterConfig::new()
 ///     .settings(settings)

diff --git a/vm/Lib/python_builtins/_py_exceptiongroup.py b/vm/Lib/python_builtins/_py_exceptiongroup.py
@@ -0,0 +1,330 @@
+# Copied from https://github.com/agronholm/ExceptionGroup/blob/1.2.1/src/exceptiongroup/_exceptions.py
+# License: https://github.com/agronholm/exceptiongroup/blob/1.2.1/LICENSE
+from __future__ import annotations
+
+from collections.abc import Callable, Sequence
+from functools import partial
+from typing import TYPE_CHECKING, Generic, Type, TypeVar, cast, overload
+
+_BaseExceptionT_co = TypeVar("_BaseExceptionT_co", bound=BaseException, covariant=True)
+_BaseExceptionT = TypeVar("_BaseExceptionT", bound=BaseException)
+_ExceptionT_co = TypeVar("_ExceptionT_co", bound=Exception, covariant=True)
+_ExceptionT = TypeVar("_ExceptionT", bound=Exception)
+# using typing.Self would require a typing_extensions dependency on py<3.11
+_ExceptionGroupSelf = TypeVar("_ExceptionGroupSelf", bound="ExceptionGroup")
+_BaseExceptionGroupSelf = TypeVar("_BaseExceptionGroupSelf", bound="BaseExceptionGroup")
+
+
+def check_direct_subclass(
+    exc: BaseException, parents: tuple[type[BaseException]]
+) -> bool:
+    from inspect import getmro  # requires rustpython-stdlib
+
+    for cls in getmro(exc.__class__)[:-1]:
+        if cls in parents:
+            return True
+
+    return False
+
+
+def get_condition_filter(
+    condition: type[_BaseExceptionT]
+    | tuple[type[_BaseExceptionT], ...]
+    | Callable[[_BaseExceptionT_co], bool],
+) -> Callable[[_BaseExceptionT_co], bool]:
+    from inspect import isclass  # requires rustpython-stdlib
+
+    if isclass(condition) and issubclass(
+        cast(Type[BaseException], condition), BaseException
+    ):
+        return partial(check_direct_subclass, parents=(condition,))
+    elif isinstance(condition, tuple):
+        if all(isclass(x) and issubclass(x, BaseException) for x in condition):
+            return partial(check_direct_subclass, parents=condition)
+    elif callable(condition):
+        return cast("Callable[[BaseException], bool]", condition)
+
+    raise TypeError("expected a function, exception type or tuple of exception types")
+
+
+def _derive_and_copy_attributes(self, excs):
+    eg = self.derive(excs)
+    eg.__cause__ = self.__cause__
+    eg.__context__ = self.__context__
+    eg.__traceback__ = self.__traceback__
+    if hasattr(self, "__notes__"):
+        # Create a new list so that add_note() only affects one exceptiongroup
+        eg.__notes__ = list(self.__notes__)
+    return eg
+
+
+class BaseExceptionGroup(BaseException, Generic[_BaseExceptionT_co]):
+    """A combination of multiple unrelated exceptions."""
+
+    def __new__(
+        cls: type[_BaseExceptionGroupSelf],
+        __message: str,
+        __exceptions: Sequence[_BaseExceptionT_co],
+    ) -> _BaseExceptionGroupSelf:
+        if not isinstance(__message, str):
+            raise TypeError(f"argument 1 must be str, not {type(__message)}")
+        if not isinstance(__exceptions, Sequence):
+            raise TypeError("second argument (exceptions) must be a sequence")
+        if not __exceptions:
+            raise ValueError(
+                "second argument (exceptions) must be a non-empty sequence"
+            )
+
+        for i, exc in enumerate(__exceptions):
+            if not isinstance(exc, BaseException):
+                raise ValueError(
+                    f"Item {i} of second argument (exceptions) is not an exception"
+                )
+
+        if cls is BaseExceptionGroup:
+            if all(isinstance(exc, Exception) for exc in __exceptions):
+                cls = ExceptionGroup
+
+        if issubclass(cls, Exception):
+            for exc in __exceptions:
+                if not isinstance(exc, Exception):
+                    if cls is ExceptionGroup:
+                        raise TypeError(
+                            "Cannot nest BaseExceptions in an ExceptionGroup"
+                        )
+                    else:
+                        raise TypeError(
+                            f"Cannot nest BaseExceptions in {cls.__name__!r}"
+                        )
+
+        instance = super().__new__(cls, __message, __exceptions)
+        instance._message = __message
+        instance._exceptions = __exceptions
+        return instance
+
+    def add_note(self, note: str) -> None:
+        if not isinstance(note, str):
+            raise TypeError(
+                f"Expected a string, got note={note!r} (type {type(note).__name__})"
+            )
+
+        if not hasattr(self, "__notes__"):
+            self.__notes__: list[str] = []
+
+        self.__notes__.append(note)
+
+    @property
+    def message(self) -> str:
+        return self._message
+
+    @property
+    def exceptions(
+        self,
+    ) -> tuple[_BaseExceptionT_co | BaseExceptionGroup[_BaseExceptionT_co], ...]:
+        return tuple(self._exceptions)
+
+    @overload
+    def subgroup(
+        self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+    ) -> ExceptionGroup[_ExceptionT] | None: ...
+
+    @overload
+    def subgroup(
+        self, __condition: type[_BaseExceptionT] | tuple[type[_BaseExceptionT], ...]
+    ) -> BaseExceptionGroup[_BaseExceptionT] | None: ...
+
+    @overload
+    def subgroup(
+        self,
+        __condition: Callable[[_BaseExceptionT_co | _BaseExceptionGroupSelf], bool],
+    ) -> BaseExceptionGroup[_BaseExceptionT_co] | None: ...
+
+    def subgroup(
+        self,
+        __condition: type[_BaseExceptionT]
+        | tuple[type[_BaseExceptionT], ...]
+        | Callable[[_BaseExceptionT_co | _BaseExceptionGroupSelf], bool],
+    ) -> BaseExceptionGroup[_BaseExceptionT] | None:
+        condition = get_condition_filter(__condition)
+        modified = False
+        if condition(self):
+            return self
+
+        exceptions: list[BaseException] = []
+        for exc in self.exceptions:
+            if isinstance(exc, BaseExceptionGroup):
+                subgroup = exc.subgroup(__condition)
+                if subgroup is not None:
+                    exceptions.append(subgroup)
+
+                if subgroup is not exc:
+                    modified = True
+            elif condition(exc):
+                exceptions.append(exc)
+            else:
+                modified = True
+
+        if not modified:
+            return self
+        elif exceptions:
+            group = _derive_and_copy_attributes(self, exceptions)
+            return group
+        else:
+            return None
+
+    @overload
+    def split(
+        self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+    ) -> tuple[
+        ExceptionGroup[_ExceptionT] | None,
+        BaseExceptionGroup[_BaseExceptionT_co] | None,
+    ]: ...
+
+    @overload
+    def split(
+        self, __condition: type[_BaseExceptionT] | tuple[type[_BaseExceptionT], ...]
+    ) -> tuple[
+        BaseExceptionGroup[_BaseExceptionT] | None,
+        BaseExceptionGroup[_BaseExceptionT_co] | None,
+    ]: ...
+
+    @overload
+    def split(
+        self,
+        __condition: Callable[[_BaseExceptionT_co | _BaseExceptionGroupSelf], bool],
+    ) -> tuple[
+        BaseExceptionGroup[_BaseExceptionT_co] | None,
+        BaseExceptionGroup[_BaseExceptionT_co] | None,
+    ]: ...
+
+    def split(
+        self,
+        __condition: type[_BaseExceptionT]
+        | tuple[type[_BaseExceptionT], ...]
+        | Callable[[_BaseExceptionT_co], bool],
+    ) -> (
+        tuple[
+            ExceptionGroup[_ExceptionT] | None,
+            BaseExceptionGroup[_BaseExceptionT_co] | None,
+        ]
+        | tuple[
+            BaseExceptionGroup[_BaseExceptionT] | None,
+            BaseExceptionGroup[_BaseExceptionT_co] | None,
+        ]
+        | tuple[
+            BaseExceptionGroup[_BaseExceptionT_co] | None,
+            BaseExceptionGroup[_BaseExceptionT_co] | None,
+        ]
+    ):
+        condition = get_condition_filter(__condition)
+        if condition(self):
+            return self, None
+
+        matching_exceptions: list[BaseException] = []
+        nonmatching_exceptions: list[BaseException] = []
+        for exc in self.exceptions:
+            if isinstance(exc, BaseExceptionGroup):
+                matching, nonmatching = exc.split(condition)
+                if matching is not None:
+                    matching_exceptions.append(matching)
+
+                if nonmatching is not None:
+                    nonmatching_exceptions.append(nonmatching)
+            elif condition(exc):
+                matching_exceptions.append(exc)
+            else:
+                nonmatching_exceptions.append(exc)
+
+        matching_group: _BaseExceptionGroupSelf | None = None
+        if matching_exceptions:
+            matching_group = _derive_and_copy_attributes(self, matching_exceptions)
+
+        nonmatching_group: _BaseExceptionGroupSelf | None = None
+        if nonmatching_exceptions:
+            nonmatching_group = _derive_and_copy_attributes(
+                self, nonmatching_exceptions
+            )
+
+        return matching_group, nonmatching_group
+
+    @overload
+    def derive(self, __excs: Sequence[_ExceptionT]) -> ExceptionGroup[_ExceptionT]: ...
+
+    @overload
+    def derive(
+        self, __excs: Sequence[_BaseExceptionT]
+    ) -> BaseExceptionGroup[_BaseExceptionT]: ...
+
+    def derive(
+        self, __excs: Sequence[_BaseExceptionT]
+    ) -> BaseExceptionGroup[_BaseExceptionT]:
+        return BaseExceptionGroup(self.message, __excs)
+
+    def __str__(self) -> str:
+        suffix = "" if len(self._exceptions) == 1 else "s"
+        return f"{self.message} ({len(self._exceptions)} sub-exception{suffix})"
+
+    def __repr__(self) -> str:
+        return f"{self.__class__.__name__}({self.message!r}, {self._exceptions!r})"
+
+
+class ExceptionGroup(BaseExceptionGroup[_ExceptionT_co], Exception):
+    def __new__(
+        cls: type[_ExceptionGroupSelf],
+        __message: str,
+        __exceptions: Sequence[_ExceptionT_co],
+    ) -> _ExceptionGroupSelf:
+        return super().__new__(cls, __message, __exceptions)
+
+    if TYPE_CHECKING:
+
+        @property
+        def exceptions(
+            self,
+        ) -> tuple[_ExceptionT_co | ExceptionGroup[_ExceptionT_co], ...]: ...
+
+        @overload  # type: ignore[override]
+        def subgroup(
+            self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+        ) -> ExceptionGroup[_ExceptionT] | None: ...
+
+        @overload
+        def subgroup(
+            self, __condition: Callable[[_ExceptionT_co | _ExceptionGroupSelf], bool]
+        ) -> ExceptionGroup[_ExceptionT_co] | None: ...
+
+        def subgroup(
+            self,
+            __condition: type[_ExceptionT]
+            | tuple[type[_ExceptionT], ...]
+            | Callable[[_ExceptionT_co], bool],
+        ) -> ExceptionGroup[_ExceptionT] | None:
+            return super().subgroup(__condition)
+
+        @overload
+        def split(
+            self, __condition: type[_ExceptionT] | tuple[type[_ExceptionT], ...]
+        ) -> tuple[
+            ExceptionGroup[_ExceptionT] | None, ExceptionGroup[_ExceptionT_co] | None
+        ]: ...
+
+        @overload
+        def split(
+            self, __condition: Callable[[_ExceptionT_co | _ExceptionGroupSelf], bool]
+        ) -> tuple[
+            ExceptionGroup[_ExceptionT_co] | None, ExceptionGroup[_ExceptionT_co] | None
+        ]: ...
+
+        def split(
+            self: _ExceptionGroupSelf,
+            __condition: type[_ExceptionT]
+            | tuple[type[_ExceptionT], ...]
+            | Callable[[_ExceptionT_co], bool],
+        ) -> tuple[
+            ExceptionGroup[_ExceptionT_co] | None, ExceptionGroup[_ExceptionT_co] | None
+        ]:
+            return super().split(__condition)
+
+
+BaseExceptionGroup.__module__ = 'builtins'
+ExceptionGroup.__module__ = 'builtins'
diff --git a/vm/src/vm/mod.rs b/vm/src/vm/mod.rs
@@ -336,8 +336,11 @@ impl VirtualMachine {
             }
         }
 
+        let expect_stdlib =
+            cfg!(feature = "freeze-stdlib") || !self.state.settings.path_list.is_empty();
+
         #[cfg(feature = "encodings")]
-        if cfg!(feature = "freeze-stdlib") || !self.state.settings.path_list.is_empty() {
+        if expect_stdlib {
             if let Err(e) = self.import_encodings() {
                 eprintln!(
                     "encodings initialization failed. Only utf-8 encoding will be supported."
@@ -354,6 +357,21 @@ impl VirtualMachine {
             );
         }
 
+        if expect_stdlib {
+            // enable python-implemented ExceptionGroup when stdlib exists
+            let py_core_init = || -> PyResult<()> {
+                let exception_group = import::import_frozen(self, "_py_exceptiongroup")?;
+                let base_exception_group = exception_group.get_attr("BaseExceptionGroup", self)?;
+                self.builtins
+                    .set_attr("BaseExceptionGroup", base_exception_group, self)?;
+                let exception_group = exception_group.get_attr("ExceptionGroup", self)?;
+                self.builtins
+                    .set_attr("ExceptionGroup", exception_group, self)?;
+                Ok(())
+            };
+            self.expect_pyresult(py_core_init(), "exceptiongroup initialization failed");
+        }
+
         self.initialized = true;
     }