diff --git a/newsfragments/3313.fixed.md b/newsfragments/3313.fixed.md new file mode 100644 index 00000000000..e5fc5c0e153 --- /dev/null +++ b/newsfragments/3313.fixed.md @@ -0,0 +1 @@ +Fix case where `PyErr::matches` and `PyErr::is_instance` returned results inconsistent with `PyErr::get_type`. diff --git a/src/err/err_state.rs b/src/err/err_state.rs index bf4fb3fdfb2..50a17fda474 100644 --- a/src/err/err_state.rs +++ b/src/err/err_state.rs @@ -68,11 +68,17 @@ impl PyErrState { ) } } - PyErrState::LazyValue { ptype, pvalue } => ( - ptype.into_ptr(), - pvalue(py).into_ptr(), - std::ptr::null_mut(), - ), + PyErrState::LazyValue { ptype, pvalue } => { + if unsafe { ffi::PyExceptionClass_Check(ptype.as_ptr()) } == 0 { + Self::exceptions_must_derive_from_base_exception(py).into_ffi_tuple(py) + } else { + ( + ptype.into_ptr(), + pvalue(py).into_ptr(), + std::ptr::null_mut(), + ) + } + } PyErrState::FfiTuple { ptype, pvalue, diff --git a/src/err/mod.rs b/src/err/mod.rs index 3af7b92bbc8..4ebb157b5d3 100644 --- a/src/err/mod.rs +++ b/src/err/mod.rs @@ -18,12 +18,13 @@ use err_state::{boxed_args, PyErrState, PyErrStateNormalized}; /// Represents a Python exception. /// -/// Python exceptions can be raised in a "lazy" fashion, where the full Python object for the -/// exception is not created until needed. The process of creating the full object is known -/// as "normalization". An exception which has not yet been created is known as "unnormalized". +/// To avoid needing access to [`Python`] in `Into` conversions to create `PyErr` (thus improving +/// compatibility with `?` and other Rust errors) this type supports creating exceptions instances +/// in a lazy fashion, where the full Python object for the exception is created only when needed. /// -/// This struct builds upon that design, supporting all lazily-created Python exceptions and also -/// supporting exceptions lazily-created from Rust. +/// Accessing the contained exception in any way, such as with [`value`](PyErr::value), +/// [`get_type`](PyErr::get_type), or [`is_instance`](PyErr::is_instance) will create the full +/// exception object if it was not already created. pub struct PyErr { // Safety: can only hand out references when in the "normalized" state. Will never change // after normalization. @@ -69,12 +70,13 @@ impl PyErr { /// * any other value: the exception instance will be created using the equivalent to the Python /// expression `T(value)` /// - /// This error will be stored in an unnormalized state. This avoids the need for the Python GIL + /// This exception instance will be initialized lazily. This avoids the need for the Python GIL /// to be held, but requires `args` to be `Send` and `Sync`. If `args` is not `Send` or `Sync`, /// consider using [`PyErr::from_value`] instead. /// - /// If an error occurs during normalization (for example if `T` is not a Python type which - /// extends from `BaseException`), then a different error may be produced during normalization. + /// If `T` does not inherit from `BaseException`, then a `TypeError` will be returned. + /// + /// If calling T's constructor with `args` raises an exception, that exception will be returned. /// /// # Examples /// @@ -130,18 +132,13 @@ impl PyErr { /// /// `args` is either a tuple or a single value, with the same meaning as in [`PyErr::new`]. /// - /// If an error occurs during normalization (for example if `T` is not a Python type which - /// extends from `BaseException`), then a different error may be produced during normalization. + /// If `ty` does not inherit from `BaseException`, then a `TypeError` will be returned. /// - /// This error will be stored in an unnormalized state. + /// If calling `ty` with `args` raises an exception, that exception will be returned. pub fn from_type(ty: &PyType, args: A) -> PyErr where A: PyErrArguments + Send + Sync + 'static, { - if unsafe { ffi::PyExceptionClass_Check(ty.as_ptr()) } == 0 { - return exceptions_must_derive_from_base_exception(ty.py()); - } - PyErr::from_state(PyErrState::LazyValue { ptype: ty.into(), pvalue: boxed_args(args), @@ -150,8 +147,7 @@ impl PyErr { /// Creates a new PyErr. /// - /// If `obj` is a Python exception object, the PyErr will contain that object. The error will be - /// in a normalized state. + /// If `obj` is a Python exception object, the PyErr will contain that object. /// /// If `obj` is a Python exception type object, this is equivalent to `PyErr::from_type(obj, ())`. /// @@ -204,8 +200,6 @@ impl PyErr { /// Returns the type of this exception. /// - /// The object will be normalized first if needed. - /// /// # Examples /// ```rust /// use pyo3::{exceptions::PyTypeError, types::PyType, PyErr, Python}; @@ -221,8 +215,6 @@ impl PyErr { /// Returns the value of this exception. /// - /// The object will be normalized first if needed. - /// /// # Examples /// /// ```rust @@ -248,8 +240,6 @@ impl PyErr { /// Returns the traceback of this exception object. /// - /// The object will be normalized first if needed. - /// /// # Examples /// ```rust /// use pyo3::{exceptions::PyTypeError, Python}; @@ -438,16 +428,13 @@ impl PyErr { where T: ToPyObject, { - fn inner(err: &PyErr, py: Python<'_>, exc: PyObject) -> bool { - (unsafe { ffi::PyErr_GivenExceptionMatches(err.type_ptr(py), exc.as_ptr()) }) != 0 - } - inner(self, py, exc.to_object(py)) + self.is_instance(py, exc.to_object(py).as_ref(py)) } /// Returns true if the current exception is instance of `T`. #[inline] pub fn is_instance(&self, py: Python<'_>, ty: &PyAny) -> bool { - (unsafe { ffi::PyErr_GivenExceptionMatches(self.type_ptr(py), ty.as_ptr()) }) != 0 + (unsafe { ffi::PyErr_GivenExceptionMatches(self.get_type(py).as_ptr(), ty.as_ptr()) }) != 0 } /// Returns true if the current exception is instance of `T`. @@ -630,19 +617,6 @@ impl PyErr { } } - /// Returns borrowed reference to this Err's type - fn type_ptr(&self, py: Python<'_>) -> *mut ffi::PyObject { - match unsafe { &*self.state.get() } { - // In lazy type case, normalize before returning ptype in case the type is not a valid - // exception type. - Some(PyErrState::LazyTypeAndValue { .. }) => self.normalized(py).ptype.as_ptr(), - Some(PyErrState::LazyValue { ptype, .. }) => ptype.as_ptr(), - Some(PyErrState::FfiTuple { ptype, .. }) => ptype.as_ptr(), - Some(PyErrState::Normalized(n)) => n.ptype.as_ptr(), - None => panic!("Cannot access exception type while normalizing"), - } - } - #[inline] fn normalized(&self, py: Python<'_>) -> &PyErrStateNormalized { if let Some(PyErrState::Normalized(n)) = unsafe { @@ -822,8 +796,8 @@ fn exceptions_must_derive_from_base_exception(py: Python<'_>) -> PyErr { #[cfg(test)] mod tests { use super::PyErrState; - use crate::exceptions; - use crate::{PyErr, Python}; + use crate::exceptions::{self, PyTypeError, PyValueError}; + use crate::{PyErr, PyTypeInfo, Python}; #[test] fn no_error() { @@ -937,6 +911,25 @@ mod tests { is_sync::(); } + #[test] + fn test_pyerr_matches() { + Python::with_gil(|py| { + let err = PyErr::new::("foo"); + assert!(err.matches(py, PyValueError::type_object(py))); + + assert!(err.matches( + py, + (PyValueError::type_object(py), PyTypeError::type_object(py)) + )); + + assert!(!err.matches(py, PyTypeError::type_object(py))); + + // String is not a valid exception class, so we should get a TypeError + let err: PyErr = PyErr::from_type(crate::types::PyString::type_object(py), "foo"); + assert!(err.matches(py, PyTypeError::type_object(py))); + }) + } + #[test] fn test_pyerr_cause() { Python::with_gil(|py| {