Expose PyDict_GetItemWithError on PyDict object

src/types/dict.rs

@@ -156,6 +156,26 @@ impl PyDict {
         }
     }
 
+    /// Gets an item from the dictionary,
+    ///
+    /// returns `Ok(None)` if item is not present, or `Err(PyErr)` if an error occurs.
+    ///
+    /// To get a `KeyError` for non-existing keys, use `PyAny::get_item_with_error`.
+    pub fn get_item_with_error<K>(&self, key: K) -> PyResult<Option<&PyAny>>
+    where
+        K: ToPyObject,
+    {
+        unsafe {
+            let ptr =
+                ffi::PyDict_GetItemWithError(self.as_ptr(), key.to_object(self.py()).as_ptr());
+            if !ffi::PyErr_Occurred().is_null() {
+                return Err(PyErr::fetch(self.py()));
+            }
+
+            Ok(NonNull::new(ptr).map(|p| self.py().from_owned_ptr(ffi::_Py_NewRef(p.as_ptr()))))
+        }
+    }
+
     /// Sets an item value.
     ///
     /// This is equivalent to the Python statement `self[key] = value`.
@@ -471,6 +491,7 @@ where
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::exceptions;
     #[cfg(not(PyPy))]
     use crate::{types::PyList, PyTypeInfo};
     use crate::{types::PyTuple, IntoPy, PyObject, PyTryFrom, Python, ToPyObject};
@@ -562,6 +583,32 @@ mod tests {
         });
     }
 
+    #[test]
+    fn test_get_item_with_error() {
+        Python::with_gil(|py| {
+            let mut v = HashMap::new();
+            v.insert(7, 32);
+            let ob = v.to_object(py);
+            let dict = <PyDict as PyTryFrom>::try_from(ob.as_ref(py)).unwrap();
+            assert_eq!(
+                32,
+                dict.get_item_with_error(7i32)
+                    .unwrap()
+                    .unwrap()
+                    .extract::<i32>()
+                    .unwrap()
+            );
+            assert!(dict.get_item_with_error(8i32).unwrap().is_none());
+
+            let dict_clone = dict.clone();
+            if let Err(err) = dict.get_item_with_error(dict_clone) {
+                assert!(err.is_instance_of::<exceptions::PyTypeError>(py));
+            } else {
+                panic!()
+            };
+        });
+    }
+
     #[test]
     fn test_set_item() {
         Python::with_gil(|py| {