array: improve test coverage

Author: davidhewitt

src/conversions/array.rs

@@ -3,70 +3,6 @@ use crate::{
     ToPyObject,
 };
 
-#[cfg(not(min_const_generics))]
-macro_rules! array_impls {
-    ($($N:expr),+) => {
-        $(
-            impl<T> IntoPy<PyObject> for [T; $N]
-            where
-                T: ToPyObject
-            {
-                fn into_py(self, py: Python) -> PyObject {
-                    self.as_ref().to_object(py)
-                }
-            }
-
-            impl<'a, T> FromPyObject<'a> for [T; $N]
-            where
-                T: Copy + Default + FromPyObject<'a>,
-            {
-                #[cfg(not(feature = "nightly"))]
-                fn extract(obj: &'a PyAny) -> PyResult<Self> {
-                    let mut array = [T::default(); $N];
-                    _extract_sequence_into_slice(obj, &mut array)?;
-                    Ok(array)
-                }
-
-                #[cfg(feature = "nightly")]
-                default fn extract(obj: &'a PyAny) -> PyResult<Self> {
-                    let mut array = [T::default(); $N];
-                    _extract_sequence_into_slice(obj, &mut array)?;
-                    Ok(array)
-                }
-            }
-
-            #[cfg(feature = "nightly")]
-            impl<'source, T> FromPyObject<'source> for [T; $N]
-            where
-                for<'a> T: Default + FromPyObject<'a> + crate::buffer::Element,
-            {
-                fn extract(obj: &'source PyAny) -> PyResult<Self> {
-                    let mut array = [T::default(); $N];
-                    // first try buffer protocol
-                    if unsafe { crate::ffi::PyObject_CheckBuffer(obj.as_ptr()) } == 1 {
-                        if let Ok(buf) = crate::buffer::PyBuffer::get(obj) {
-                            if buf.dimensions() == 1 && buf.copy_to_slice(obj.py(), &mut array).is_ok() {
-                                buf.release(obj.py());
-                                return Ok(array);
-                            }
-                            buf.release(obj.py());
-                        }
-                    }
-                    // fall back to sequence protocol
-                    _extract_sequence_into_slice(obj, &mut array)?;
-                    Ok(array)
-                }
-            }
-        )+
-    }
-}
-
-#[cfg(not(min_const_generics))]
-array_impls!(
-    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
-    26, 27, 28, 29, 30, 31, 32
-);
-
 #[cfg(min_const_generics)]
 impl<T, const N: usize> IntoPy<PyObject> for [T; N]
 where
@@ -100,20 +36,18 @@ where
 {
     fn extract(obj: &'source PyAny) -> PyResult<Self> {
         use crate::{AsPyPointer, PyNativeType};
-        let mut array = [T::default(); N];
         // first try buffer protocol
         if unsafe { crate::ffi::PyObject_CheckBuffer(obj.as_ptr()) } == 1 {
             if let Ok(buf) = crate::buffer::PyBuffer::get(obj) {
+                let mut array = [T::default(); N];
                 if buf.dimensions() == 1 && buf.copy_to_slice(obj.py(), &mut array).is_ok() {
                     buf.release(obj.py());
                     return Ok(array);
                 }
                 buf.release(obj.py());
             }
         }
-        // fall back to sequence protocol
-        _extract_sequence_into_slice(obj, &mut array)?;
-        Ok(array)
+        create_array_from_obj(obj)
     }
 }
 
@@ -123,12 +57,11 @@ where
     T: FromPyObject<'s>,
 {
     let seq = <crate::types::PySequence as PyTryFrom>::try_from(obj)?;
-    let expected_len = seq.len()? as usize;
-    array_try_from_fn(|idx| {
-        seq.get_item(idx as isize)
-            .map_err(|_| invalid_sequence_length(expected_len, idx + 1))?
-            .extract::<T>()
-    })
+    let seq_len = seq.len()? as usize;
+    if seq_len != N {
+        return Err(invalid_sequence_length(N, seq_len));
+    }
+    array_try_from_fn(|idx| seq.get_item(idx as isize).and_then(PyAny::extract))
 }
 
 // TODO use std::array::try_from_fn, if that stabilises:
@@ -174,7 +107,72 @@ where
     }
 }
 
-fn _extract_sequence_into_slice<'s, T>(obj: &'s PyAny, slice: &mut [T]) -> PyResult<()>
+#[cfg(not(min_const_generics))]
+macro_rules! array_impls {
+    ($($N:expr),+) => {
+        $(
+            impl<T> IntoPy<PyObject> for [T; $N]
+            where
+                T: ToPyObject
+            {
+                fn into_py(self, py: Python) -> PyObject {
+                    self.as_ref().to_object(py)
+                }
+            }
+
+            impl<'a, T> FromPyObject<'a> for [T; $N]
+            where
+                T: Copy + Default + FromPyObject<'a>,
+            {
+                #[cfg(not(feature = "nightly"))]
+                fn extract(obj: &'a PyAny) -> PyResult<Self> {
+                    let mut array = [T::default(); $N];
+                    extract_sequence_into_slice(obj, &mut array)?;
+                    Ok(array)
+                }
+
+                #[cfg(feature = "nightly")]
+                default fn extract(obj: &'a PyAny) -> PyResult<Self> {
+                    let mut array = [T::default(); $N];
+                    extract_sequence_into_slice(obj, &mut array)?;
+                    Ok(array)
+                }
+            }
+
+            #[cfg(feature = "nightly")]
+            impl<'source, T> FromPyObject<'source> for [T; $N]
+            where
+                for<'a> T: Default + FromPyObject<'a> + crate::buffer::Element,
+            {
+                fn extract(obj: &'source PyAny) -> PyResult<Self> {
+                    let mut array = [T::default(); $N];
+                    // first try buffer protocol
+                    if unsafe { crate::ffi::PyObject_CheckBuffer(obj.as_ptr()) } == 1 {
+                        if let Ok(buf) = crate::buffer::PyBuffer::get(obj) {
+                            if buf.dimensions() == 1 && buf.copy_to_slice(obj.py(), &mut array).is_ok() {
+                                buf.release(obj.py());
+                                return Ok(array);
+                            }
+                            buf.release(obj.py());
+                        }
+                    }
+                    // fall back to sequence protocol
+                    extract_sequence_into_slice(obj, &mut array)?;
+                    Ok(array)
+                }
+            }
+        )+
+    }
+}
+
+#[cfg(not(min_const_generics))]
+array_impls!(
+    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
+    26, 27, 28, 29, 30, 31, 32
+);
+
+#[cfg(not(min_const_generics))]
+fn extract_sequence_into_slice<'s, T>(obj: &'s PyAny, slice: &mut [T]) -> PyResult<()>
 where
     T: FromPyObject<'s>,
 {
@@ -189,7 +187,7 @@ where
     Ok(())
 }
 
-pub fn invalid_sequence_length(expected: usize, actual: usize) -> PyErr {
+fn invalid_sequence_length(expected: usize, actual: usize) -> PyErr {
     exceptions::PyValueError::new_err(format!(
         "expected a sequence of length {} (got {})",
         expected, actual
@@ -198,7 +196,7 @@ pub fn invalid_sequence_length(expected: usize, actual: usize) -> PyErr {
 
 #[cfg(test)]
 mod test {
-    use crate::Python;
+    use crate::{PyResult, Python};
     #[cfg(min_const_generics)]
     use std::{
         panic,
@@ -238,6 +236,20 @@ mod test {
         assert!(&v == b"abc");
     }
 
+    #[test]
+    fn test_extract_invalid_sequence_length() {
+        let gil = Python::acquire_gil();
+        let py = gil.python();
+        let v: PyResult<[u8; 3]> = py
+            .eval("bytearray(b'abcdefg')", None, None)
+            .unwrap()
+            .extract();
+        assert_eq!(
+            v.unwrap_err().to_string(),
+            "ValueError: expected a sequence of length 3 (got 7)"
+        );
+    }
+
     #[cfg(min_const_generics)]
     #[test]
     fn test_extract_bytearray_to_array() {

src/conversions/mod.rs

@@ -1,5 +1,4 @@
-//! This module contains conversions between non-String Rust object and their string representation
-//! in Python
+//! This module contains conversions between various Rust object and their representation in Python.
 
 mod array;
 mod osstr;