[RFC] split PyErr::new() into multiple methods

examples/getitem/src/lib.rs

@@ -55,7 +55,7 @@ impl ExampleContainer {
 
             return Ok(delta);
         } else {
-            return Err(PyTypeError::new_err("Unsupported type"));
+            return Err(PyTypeError::new_err_arg("Unsupported type"));
         }
     }
     fn __setitem__(&self, idx: IntOrSlice, value: u32) -> PyResult<()> {

guide/src/class.md

@@ -158,7 +158,7 @@ impl Nonzero {
     #[new]
     fn py_new(value: i32) -> PyResult<Self> {
         if value == 0 {
-            Err(PyValueError::new_err("cannot be zero"))
+            Err(PyValueError::new_err_arg("cannot be zero"))
         } else {
             Ok(Nonzero(value))
         }

guide/src/class/numeric.md

@@ -95,28 +95,28 @@ impl Number {
     fn __truediv__(&self, other: &Self) -> PyResult<Self> {
         match self.0.checked_div(other.0) {
             Some(i) => Ok(Self(i)),
-            None => Err(PyZeroDivisionError::new_err("division by zero")),
+            None => Err(PyZeroDivisionError::new_err_arg("division by zero")),
         }
     }
 
     fn __floordiv__(&self, other: &Self) -> PyResult<Self> {
         match self.0.checked_div(other.0) {
             Some(i) => Ok(Self(i)),
-            None => Err(PyZeroDivisionError::new_err("division by zero")),
+            None => Err(PyZeroDivisionError::new_err_arg("division by zero")),
         }
     }
 
     fn __rshift__(&self, other: &Self) -> PyResult<Self> {
         match other.0.try_into() {
             Ok(rhs) => Ok(Self(self.0.wrapping_shr(rhs))),
-            Err(_) => Err(PyValueError::new_err("negative shift count")),
+            Err(_) => Err(PyValueError::new_err_arg("negative shift count")),
         }
     }
 
     fn __lshift__(&self, other: &Self) -> PyResult<Self> {
         match other.0.try_into() {
             Ok(rhs) => Ok(Self(self.0.wrapping_shl(rhs))),
-            Err(_) => Err(PyValueError::new_err("negative shift count")),
+            Err(_) => Err(PyValueError::new_err_arg("negative shift count")),
         }
     }
 }
@@ -275,28 +275,28 @@ impl Number {
     fn __truediv__(&self, other: &Self) -> PyResult<Self> {
         match self.0.checked_div(other.0) {
             Some(i) => Ok(Self(i)),
-            None => Err(PyZeroDivisionError::new_err("division by zero")),
+            None => Err(PyZeroDivisionError::new_err_arg("division by zero")),
         }
     }
 
     fn __floordiv__(&self, other: &Self) -> PyResult<Self> {
         match self.0.checked_div(other.0) {
             Some(i) => Ok(Self(i)),
-            None => Err(PyZeroDivisionError::new_err("division by zero")),
+            None => Err(PyZeroDivisionError::new_err_arg("division by zero")),
         }
     }
 
     fn __rshift__(&self, other: &Self) -> PyResult<Self> {
         match other.0.try_into() {
             Ok(rhs) => Ok(Self(self.0.wrapping_shr(rhs))),
-            Err(_) => Err(PyValueError::new_err("negative shift count")),
+            Err(_) => Err(PyValueError::new_err_arg("negative shift count")),
         }
     }
 
     fn __lshift__(&self, other: &Self) -> PyResult<Self> {
         match other.0.try_into() {
             Ok(rhs) => Ok(Self(self.0.wrapping_shl(rhs))),
-            Err(_) => Err(PyValueError::new_err("negative shift count")),
+            Err(_) => Err(PyValueError::new_err_arg("negative shift count")),
         }
     }
 

guide/src/exception.md

@@ -63,7 +63,7 @@ use pyo3::{Python, PyErr};
 use pyo3::exceptions::PyTypeError;
 
 Python::with_gil(|py| {
-    PyTypeError::new_err("Error").restore(py);
+    PyTypeError::new_err_arg("Error").restore(py);
     assert!(PyErr::occurred(py));
     drop(PyErr::fetch(py));
 });
@@ -92,7 +92,7 @@ To check the type of an exception, you can similarly do:
 # use pyo3::exceptions::PyTypeError;
 # use pyo3::prelude::*;
 # Python::with_gil(|py| {
-# let err = PyTypeError::new_err(());
+# let err = PyTypeError::new_err_empty();
 err.is_instance_of::<PyTypeError>(py);
 # });
 ```
@@ -113,7 +113,7 @@ mod io {
 
 fn tell(file: &Bound<'_, PyAny>) -> PyResult<u64> {
     match file.call_method0("tell") {
-        Err(_) => Err(io::UnsupportedOperation::new_err("not supported: tell")),
+        Err(_) => Err(io::UnsupportedOperation::new_err_arg("not supported: tell")),
         Ok(x) => x.extract::<u64>(),
     }
 }

guide/src/function/error-handling.md

@@ -36,7 +36,7 @@ use pyo3::prelude::*;
 #[pyfunction]
 fn check_positive(x: i32) -> PyResult<()> {
     if x < 0 {
-        Err(PyValueError::new_err("x is negative"))
+        Err(PyValueError::new_err_arg("x is negative"))
     } else {
         Ok(())
     }
@@ -109,7 +109,7 @@ impl fmt::Display for CustomIOError {
 
 impl std::convert::From<CustomIOError> for PyErr {
     fn from(err: CustomIOError) -> PyErr {
-        PyOSError::new_err(err.to_string())
+        PyOSError::new_err_arg(err.to_string())
     }
 }
 
@@ -205,7 +205,7 @@ struct MyOtherError(OtherError);
 
 impl From<MyOtherError> for PyErr {
     fn from(error: MyOtherError) -> Self {
-        PyValueError::new_err(error.0.message())
+        PyValueError::new_err_arg(error.0.message())
     }
 }
 

guide/src/migration.md

@@ -439,7 +439,7 @@ impl PyClassIter {
             self.count += 1;
             Ok(self.count)
         } else {
-            Err(PyStopIteration::new_err("done"))
+            Err(PyStopIteration::new_err_arg("done"))
         }
     }
 }
@@ -852,7 +852,7 @@ When converting from `anyhow::Error` or `eyre::Report` to `PyErr`, if the inner
 # use pyo3::exceptions::PyValueError;
 #[pyfunction]
 fn raise_err() -> anyhow::Result<()> {
-    Err(PyValueError::new_err("original error message").into())
+    Err(PyValueError::new_err_arg("original error message").into())
 }
 
 fn main() {
@@ -1517,7 +1517,7 @@ let result: PyResult<()> = PyErr::new::<TypeError, _>("error message").into();
 After (also using the new reworked exception types; see the following section):
 ```rust
 # use pyo3::{PyResult, exceptions::PyTypeError};
-let result: PyResult<()> = Err(PyTypeError::new_err("error message"));
+let result: PyResult<()> = Err(PyTypeError::new_err_arg("error message"));
 ```
 </details>
 
@@ -1541,7 +1541,7 @@ After:
 # use pyo3::{PyErr, PyResult, Python, type_object::PyTypeObject};
 # use pyo3::exceptions::{PyBaseException, PyTypeError};
 # Python::with_gil(|py| -> PyResult<()> {
-let err: PyErr = PyTypeError::new_err("error message");
+let err: PyErr = PyTypeError::new_err_arg("error message");
 
 // Uses Display for PyErr, new for PyO3 0.12
 assert_eq!(err.to_string(), "TypeError: error message");

guide/src/performance.md

@@ -26,7 +26,7 @@ fn frobnicate<'py>(value: &Bound<'py, PyAny>) -> PyResult<Bound<'py, PyAny>> {
     } else if let Ok(vec) = value.extract::<Vec<Bound<'_, PyAny>>>() {
         frobnicate_vec(vec)
     } else {
-        Err(PyTypeError::new_err("Cannot frobnicate that type."))
+        Err(PyTypeError::new_err_arg("Cannot frobnicate that type."))
     }
 }
 ```
@@ -48,7 +48,7 @@ fn frobnicate<'py>(value: &Bound<'py, PyAny>) -> PyResult<Bound<'py, PyAny>> {
     } else if let Ok(vec) = value.extract::<Vec<Bound<'_, PyAny>>>() {
         frobnicate_vec(vec)
     } else {
-        Err(PyTypeError::new_err("Cannot frobnicate that type."))
+        Err(PyTypeError::new_err_arg("Cannot frobnicate that type."))
     }
 }
 ```

pyo3-benches/benches/bench_err.rs

@@ -5,14 +5,14 @@ use pyo3::{exceptions::PyValueError, prelude::*};
 fn err_new_restore_and_fetch(b: &mut Bencher<'_>) {
     Python::with_gil(|py| {
         b.iter(|| {
-            PyValueError::new_err("some exception message").restore(py);
+            PyValueError::new_err_arg("some exception message").restore(py);
             PyErr::fetch(py)
         })
     })
 }
 
 fn err_new_without_gil(b: &mut Bencher<'_>) {
-    b.iter(|| PyValueError::new_err("some exception message"))
+    b.iter(|| PyValueError::new_err_arg("some exception message"))
 }
 
 fn criterion_benchmark(c: &mut Criterion) {

pyo3-macros-backend/src/pyclass.rs

@@ -1351,7 +1351,7 @@ fn impl_complex_enum_tuple_variant_getitem(
             let py = slf.py();
             match idx {
                 #( #match_arms, )*
-                _ => ::std::result::Result::Err(#pyo3_path::exceptions::PyIndexError::new_err("tuple index out of range")),
+                _ => ::std::result::Result::Err(#pyo3_path::exceptions::PyIndexError::new_err_arg("tuple index out of range")),
             }
         }
     };

pyo3-macros-backend/src/pymethod.rs

@@ -679,7 +679,7 @@ pub fn impl_py_setter_def(
             use ::std::convert::Into;
             let _value = #pyo3_path::impl_::pymethods::BoundRef::ref_from_ptr_or_opt(py, &_value)
                 .ok_or_else(|| {
-                    #pyo3_path::exceptions::PyAttributeError::new_err("can't delete attribute")
+                    #pyo3_path::exceptions::PyAttributeError::new_err_arg("can't delete attribute")
                 })?;
             #init_holders
             #extract
@@ -1100,15 +1100,15 @@ impl Ty {
             Ty::CompareOp => extract_error_mode.handle_error(
                 quote! {
                     #pyo3_path::class::basic::CompareOp::from_raw(#ident)
-                        .ok_or_else(|| #pyo3_path::exceptions::PyValueError::new_err("invalid comparison operator"))
+                        .ok_or_else(|| #pyo3_path::exceptions::PyValueError::new_err_arg("invalid comparison operator"))
                 },
                 ctx
             ),
             Ty::PySsizeT => {
                 let ty = arg.ty();
                 extract_error_mode.handle_error(
                     quote! {
-                            ::std::convert::TryInto::<#ty>::try_into(#ident).map_err(|e| #pyo3_path::exceptions::PyValueError::new_err(e.to_string()))
+                            ::std::convert::TryInto::<#ty>::try_into(#ident).map_err(|e| #pyo3_path::exceptions::PyValueError::new_err_arg(e.to_string()))
                     },
                     ctx
                 )

pytests/src/awaitable.rs

@@ -34,7 +34,7 @@ impl IterAwaitable {
     fn __next__(&mut self, py: Python<'_>) -> PyResult<PyObject> {
         match self.result.take() {
             Some(res) => match res {
-                Ok(v) => Err(PyStopIteration::new_err(v)),
+                Ok(v) => Err(PyStopIteration::new_err_arg(v)),
                 Err(err) => Err(err),
             },
             _ => Ok(py.None()),
@@ -70,7 +70,7 @@ impl FutureAwaitable {
     fn __next__(mut pyself: PyRefMut<'_, Self>) -> PyResult<PyRefMut<'_, Self>> {
         match pyself.result {
             Some(_) => match pyself.result.take().unwrap() {
-                Ok(v) => Err(PyStopIteration::new_err(v)),
+                Ok(v) => Err(PyStopIteration::new_err_arg(v)),
                 Err(err) => Err(err),
             },
             _ => Ok(pyself),

pytests/src/dict_iter.rs

@@ -33,7 +33,7 @@ impl DictSize {
         if seen == self.expected {
             Ok(seen)
         } else {
-            Err(PyErr::new::<PyRuntimeError, _>(format!(
+            Err(PyErr::new_arg::<PyRuntimeError, _>(format!(
                 "Expected {} iterations - performed {}",
                 self.expected, seen
             )))

pytests/src/pyclasses.rs

@@ -38,7 +38,7 @@ impl PyClassIter {
             self.count += 1;
             Ok(self.count)
         } else {
-            Err(PyStopIteration::new_err("Ended"))
+            Err(PyStopIteration::new_err_arg("Ended"))
         }
     }
 }
@@ -54,7 +54,7 @@ impl AssertingBaseClass {
     #[classmethod]
     fn new(cls: &Bound<'_, PyType>, expected_type: Bound<'_, PyType>) -> PyResult<Self> {
         if !cls.is(&expected_type) {
-            return Err(PyValueError::new_err(format!(
+            return Err(PyValueError::new_err_arg(format!(
                 "{:?} != {:?}",
                 cls, expected_type
             )));

src/buffer.rs

@@ -206,16 +206,16 @@ impl<T: Element> PyBuffer<T> {
         let buf = PyBuffer(Pin::from(buf), PhantomData);
 
         if buf.0.shape.is_null() {
-            Err(PyBufferError::new_err("shape is null"))
+            Err(PyBufferError::new_err_arg("shape is null"))
         } else if buf.0.strides.is_null() {
-            Err(PyBufferError::new_err("strides is null"))
+            Err(PyBufferError::new_err_arg("strides is null"))
         } else if mem::size_of::<T>() != buf.item_size() || !T::is_compatible_format(buf.format()) {
-            Err(PyBufferError::new_err(format!(
+            Err(PyBufferError::new_err_arg(format!(
                 "buffer contents are not compatible with {}",
                 std::any::type_name::<T>()
             )))
         } else if buf.0.buf.align_offset(mem::align_of::<T>()) != 0 {
-            Err(PyBufferError::new_err(format!(
+            Err(PyBufferError::new_err_arg(format!(
                 "buffer contents are insufficiently aligned for {}",
                 std::any::type_name::<T>()
             )))
@@ -476,7 +476,7 @@ impl<T: Element> PyBuffer<T> {
 
     fn _copy_to_slice(&self, py: Python<'_>, target: &mut [T], fort: u8) -> PyResult<()> {
         if mem::size_of_val(target) != self.len_bytes() {
-            return Err(PyBufferError::new_err(format!(
+            return Err(PyBufferError::new_err_arg(format!(
                 "slice to copy to (of length {}) does not match buffer length of {}",
                 target.len(),
                 self.item_count()
@@ -568,9 +568,11 @@ impl<T: Element> PyBuffer<T> {
 
     fn _copy_from_slice(&self, py: Python<'_>, source: &[T], fort: u8) -> PyResult<()> {
         if self.readonly() {
-            return Err(PyBufferError::new_err("cannot write to read-only buffer"));
+            return Err(PyBufferError::new_err_arg(
+                "cannot write to read-only buffer",
+            ));
         } else if mem::size_of_val(source) != self.len_bytes() {
-            return Err(PyBufferError::new_err(format!(
+            return Err(PyBufferError::new_err_arg(format!(
                 "slice to copy from (of length {}) does not match buffer length of {}",
                 source.len(),
                 self.item_count()

src/callback.rs

@@ -84,7 +84,8 @@ impl IntoPyCallbackOutput<()> for () {
 impl IntoPyCallbackOutput<ffi::Py_ssize_t> for usize {
     #[inline]
     fn convert(self, _py: Python<'_>) -> PyResult<ffi::Py_ssize_t> {
-        self.try_into().map_err(|_err| PyOverflowError::new_err(()))
+        self.try_into()
+            .map_err(|_err| PyOverflowError::new_err_empty())
     }
 }
 

src/conversions/anyhow.rs

@@ -114,7 +114,7 @@ impl From<anyhow::Error> for PyErr {
                 Err(error) => error,
             };
         }
-        PyRuntimeError::new_err(format!("{:?}", error))
+        PyRuntimeError::new_err_arg(format!("{:?}", error))
     }
 }
 
@@ -175,7 +175,7 @@ mod test_anyhow {
 
     #[test]
     fn test_pyo3_unwrap_simple_err() {
-        let origin_exc = PyValueError::new_err("Value Error");
+        let origin_exc = PyValueError::new_err_empty();
         let err: anyhow::Error = origin_exc.into();
         let converted: PyErr = err.into();
         assert!(Python::with_gil(
@@ -184,7 +184,7 @@ mod test_anyhow {
     }
     #[test]
     fn test_pyo3_unwrap_complex_err() {
-        let origin_exc = PyValueError::new_err("Value Error");
+        let origin_exc = PyValueError::new_err_empty();
         let mut err: anyhow::Error = origin_exc.into();
         err = err.context("Context");
         let converted: PyErr = err.into();