Struct cpython::PyErr

pub struct PyErr {
    pub ptype: PyObject,
    pub pvalue: Option<PyObject>,
    pub ptraceback: Option<PyObject>,
}

Represents a Python exception that was raised.

Fields

ptype: PyObject

The type of the exception. This should be either a PyClass or a PyType.

pvalue: Option<PyObject>

The value of the exception.

This can be either an instance of ptype, a tuple of arguments to be passed to ptype's constructor, or a single argument to be passed to ptype's constructor. Call PyErr::instance() to get the exception instance in all cases.

ptraceback: Option<PyObject>

The PyTraceBack object associated with the error.

Implementations

impl PyErr

pub fn new<T, V>(py: Python<'_>, value: V) -> PyErr where
    T: PythonObjectWithTypeObject,
    V: ToPyObject, 

Creates a new PyErr of type T.

value can be:

• NoArgs: the exception instance will be created using python T()
• a tuple: the exception instance will be created using python T(*tuple)
• any other value: the exception instance will be created using python T(value)

Panics if T is not a python class derived from BaseException.

Example: return Err(PyErr::new::<exc::TypeError, _>(py, "Error message"));

pub fn occurred(_: Python<'_>) -> bool

Gets whether an error is present in the Python interpreter's global state.

pub fn new_type(
    py: Python<'_>,
    name: &str,
    base: Option<PyObject>,
    dict: Option<PyObject>
) -> PyType

Creates a new exception type with the given name, which must be of the form <module>.<ExceptionName>, as required by PyErr_NewException.

base can be an existing exception type to subclass, or a tuple of classes dict specifies an optional dictionary of class variables and methods

pub fn fetch(py: Python<'_>) -> PyErr

Retrieves the current error from the Python interpreter's global state. The error is cleared from the Python interpreter. If no error is set, returns a SystemError.

pub fn from_instance<O>(py: Python<'_>, obj: O) -> PyErr where
    O: PythonObject, 

Creates a new PyErr.

obj must be an Python exception instance, the PyErr will use that instance. If obj is a Python exception type object, the PyErr will (lazily) create a new instance of that type. Otherwise, a TypeError is created instead.

pub fn new_lazy_init(exc: PyType, value: Option<PyObject>) -> PyErr

Construct a new error, with the usual lazy initialization of Python exceptions. exc is the exception type; usually one of the standard exceptions like py.get_type::<exc::RuntimeError>(). value is the exception instance, or a tuple of arguments to pass to the exception constructor.

pub fn print(self, py: Python<'_>)

Print a standard traceback to sys.stderr.

pub fn print_and_set_sys_last_vars(self, py: Python<'_>)

Print a standard traceback to sys.stderr.

pub fn matches<T>(&self, py: Python<'_>, exc: T) -> bool where
    T: ToPyObject, 

Return true if the current exception matches the exception in exc. If exc is a class object, this also returns true when self is an instance of a subclass. If exc is a tuple, all exceptions in the tuple (and recursively in subtuples) are searched for a match.

pub fn normalize(&mut self, py: Python<'_>)

Normalizes the error. This ensures that the exception value is an instance of the exception type.

pub fn get_type(&self, py: Python<'_>) -> PyType

Retrieves the exception type.

If the exception type is an old-style class, returns oldstyle::PyClass.

pub fn instance(&mut self, py: Python<'_>) -> PyObject

Retrieves the exception instance for this error. This method takes &mut self because the error might need to be normalized in order to create the exception instance.

pub fn restore(self, py: Python<'_>)

Writes the error back to the Python interpreter's global state. This is the opposite of PyErr::fetch().

pub fn warn(
    py: Python<'_>,
    category: &PyObject,
    message: &str,
    stacklevel: i32
) -> PyResult<()>

Issue a warning message. May return a PyErr if warnings-as-errors is enabled.

Trait Implementations

impl Debug for PyErr

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Error> for PyErr

fn from(error: Error) -> Self

Performs the conversion.

impl From<PyErr> for Error

fn from(err: PyErr) -> Self

Performs the conversion.

impl<'p> From<PythonObjectDowncastError<'p>> for PyErr

Converts PythonObjectDowncastError to Python TypeError.

fn from(err: PythonObjectDowncastError<'p>) -> PyErr

Performs the conversion.

impl PyClone for PyErr

fn clone_ref(&self, py: Python<'_>) -> PyErr

impl PyDrop for PyErr

fn release_ref(self, py: Python<'_>)