Dont dump none entity

.gitignore

@@ -17,3 +17,4 @@ __pycache__/
 .coverage
 .auto-format
 /toml-test/
+/.env/

rtoml/__init__.py

@@ -34,7 +34,7 @@ def loads(toml: str) -> Dict[str, Any]:
     return _rtoml.deserialize(toml)
 
 
-def dumps(obj: Any, *, pretty: bool = False) -> str:
+def dumps(obj: Any, *, pretty: bool = False, omit_none: bool = False) -> str:
     """
     Serialize a python object to TOML.
 
@@ -45,7 +45,7 @@ def dumps(obj: Any, *, pretty: bool = False) -> str:
     else:
         serialize = _rtoml.serialize
 
-    return serialize(obj)
+    return serialize(obj, omit_none);
 
 
 def dump(obj: Any, file: Union[Path, TextIO], *, pretty: bool = False) -> int:

rtoml/_rtoml.pyi

@@ -4,8 +4,8 @@ from typing import Any, Callable, Union
 VERSION: str
 
 def deserialize(toml: str) -> Any: ...
-def serialize(obj: Any) -> str: ...
-def serialize_pretty(obj: Any) -> str: ...
+def serialize(obj: Any, omitNone: bool) -> str: ...
+def serialize_pretty(obj: Any, omitNone: bool) -> str: ...
 
 class TomlParsingError(ValueError): ...
 class TomlSerializationError(ValueError): ...

src/lib.rs

@@ -2,7 +2,7 @@ extern crate pyo3;
 
 use pyo3::exceptions::PyValueError;
 use pyo3::prelude::*;
-use pyo3::types::{PyAny, PyDateTime, PyDict, PyFloat, PyList, PyTuple};
+use pyo3::types::{PyAny, PyDateTime, PyDict, PyFloat, PyList, PyTuple, PyBool};
 use pyo3::{create_exception, wrap_pyfunction, PyErrArguments};
 use serde::ser::{self, Serialize, SerializeMap, SerializeSeq, Serializer};
 use std::str::FromStr;
@@ -49,12 +49,26 @@ fn deserialize(py: Python, toml: String) -> PyResult<PyObject> {
 }
 
 // taken from https://github.com/mre/hyperjson/blob/10d31608584ef4499d6b6b10b6dc9455b358fe3d/src/lib.rs#L287-L402
-struct SerializePyObject<'p, 'a> {
+struct SerializePyObject<'p> {
     py: Python<'p>,
-    obj: &'a PyAny,
+    obj: &'p PyAny,
+    omit_none: bool,
 }
 
-impl<'p, 'a> Serialize for SerializePyObject<'p, 'a> {
+impl<'p> SerializePyObject<'p> {
+    fn new(py: Python<'p>, obj: &'p PyObject, omit_none: &PyObject) -> PyResult<Self> {
+        let omit_none = omit_none.extract::<&PyBool>(py)?.is_true();
+        let obj = obj.extract(py)?;
+
+        Ok(Self {
+            py,
+            omit_none,
+            obj,
+        })
+    }
+}
+
+impl<'p> Serialize for SerializePyObject<'p> {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
         S: Serializer,
@@ -83,23 +97,29 @@ impl<'p, 'a> Serialize for SerializePyObject<'p, 'a> {
 
         macro_rules! add_to_map {
             ($map:ident, $key:ident, $value:ident) => {
-                if $key.is_none() {
-                    $map.serialize_key("null")?;
-                } else if let Ok(key) = $key.extract::<bool>() {
-                    $map.serialize_key(if key { "true" } else { "false" })?;
-                } else if let Ok(key) = $key.str() {
-                    let key = key.to_string();
-                    $map.serialize_key(&key)?;
+                if self.omit_none && $value.is_none() {
+                    // in case of none we don't need to serialize anything
+                    // we just ingore this field.
                 } else {
-                    return Err(ser::Error::custom(format_args!(
-                        "Dictionary key is not a string: {:?}",
-                        $key
-                    )));
+                    if $key.is_none() {
+                        $map.serialize_key("null")?;
+                    } else if let Ok(key) = $key.extract::<bool>() {
+                        $map.serialize_key(if key { "true" } else { "false" })?;
+                    } else if let Ok(key) = $key.str() {
+                        let key = key.to_string();
+                        $map.serialize_key(&key)?;
+                    } else {
+                        return Err(ser::Error::custom(format_args!(
+                            "Dictionary key is not a string: {:?}",
+                            $key
+                        )));
+                    }
+                    $map.serialize_value(&SerializePyObject {
+                        py: self.py,
+                        obj: $value,
+                        omit_none: self.omit_none,
+                    })?;
                 }
-                $map.serialize_value(&SerializePyObject {
-                    py: self.py,
-                    obj: $value,
-                })?;
             };
         }
 
@@ -135,9 +155,15 @@ impl<'p, 'a> Serialize for SerializePyObject<'p, 'a> {
                 cast!(|x: $type| {
                     let mut seq = serializer.serialize_seq(Some(x.len()))?;
                     for element in x {
+                        if self.omit_none && element.is_none() {
+                            // None values must be omitted
+                            continue
+                        }
+
                         seq.serialize_element(&SerializePyObject {
                             py: self.py,
                             obj: element,
+                            omit_none: self.omit_none,
                         })?
                     }
                     return seq.end();
@@ -183,24 +209,18 @@ impl<'p, 'a> Serialize for SerializePyObject<'p, 'a> {
 }
 
 #[pyfunction]
-fn serialize(py: Python, obj: PyObject) -> PyResult<String> {
-    let s = SerializePyObject {
-        py,
-        obj: obj.extract(py)?,
-    };
-    match to_toml_string(&s) {
+fn serialize(py: Python, obj: PyObject, omit_none: PyObject) -> PyResult<String> {
+    let serializer = SerializePyObject::new(py, &obj, &omit_none)?;
+    match to_toml_string(&serializer) {
         Ok(s) => Ok(s),
         Err(e) => Err(TomlSerializationError::new_err(e.to_string())),
     }
 }
 
 #[pyfunction]
-fn serialize_pretty(py: Python, obj: PyObject) -> PyResult<String> {
-    let s = SerializePyObject {
-        py,
-        obj: obj.extract(py)?,
-    };
-    match to_toml_string_pretty(&s) {
+fn serialize_pretty(py: Python, obj: PyObject, omit_none: PyObject) -> PyResult<String> {
+    let serializer = SerializePyObject::new(py, &obj, &omit_none)?;
+    match to_toml_string_pretty(&serializer) {
         Ok(s) => Ok(s),
         Err(e) => Err(TomlSerializationError::new_err(e.to_string())),
     }

tests/test_dump.py

@@ -61,3 +61,48 @@ def test_dump_file(tmp_path):
 
 def test_varied_list():
     assert rtoml.dumps({'test': [1, '2']}) == 'test = [1, "2"]\n'
+
+
+@pytest.mark.parametrize(
+    'input_obj,output_toml',
+    [
+        ({'key': None}, ''),
+        ({'foo': 'bar', 'key1': None}, 'foo = "bar"\n'),
+        ({'key1': None, 'foo': 'bar'}, 'foo = "bar"\n'),
+        ({'key1': None, 'foo': 'bar', 'key2': None}, 'foo = "bar"\n'),
+    ],
+)
+def test_none_map_value(input_obj, output_toml):
+    assert rtoml.dumps(input_obj, omit_none=True) == output_toml
+
+@pytest.mark.parametrize(
+    'input_obj,output_toml',
+    [
+        ([None], '[]'),
+        (["a", None], '["a"]'),
+        ([None, "b"], '["b"]'),
+        (["a", None, "b"], '["a", "b"]'),
+        ({'foo': 'bar', 'list': [None]}, 'foo = "bar"\nlist = []\n'),
+        ({'foo': 'bar', 'list': [None, "b"]}, 'foo = "bar"\nlist = ["b"]\n'),
+        ({'foo': 'bar', 'list': ["a", None]}, 'foo = "bar"\nlist = ["a"]\n'),
+        ({'foo': 'bar', 'list': ["a", None, "b"]}, 'foo = "bar"\nlist = ["a", "b"]\n'),
+    ],
+)
+def test_none_values_inside_list(input_obj, output_toml):
+    assert rtoml.dumps(input_obj, omit_none=True) == output_toml
+
+@pytest.mark.parametrize(
+    'input_obj,output_toml',
+    [
+        ((None), '"null"'),
+        (("a", None), '["a"]'),
+        ((None, "b"), '["b"]'),
+        (("a", None, "b"), '["a", "b"]'),
+        ({'foo': 'bar', 'list': (None)}, 'foo = "bar"\n'),
+        ({'foo': 'bar', 'list': (None, "b")}, 'foo = "bar"\nlist = ["b"]\n'),
+        ({'foo': 'bar', 'list': ("a", None)}, 'foo = "bar"\nlist = ["a"]\n'),
+        ({'foo': 'bar', 'list': ("a", None, "b")}, 'foo = "bar"\nlist = ["a", "b"]\n'),
+    ],
+)
+def test_none_values_inside_tuple(input_obj, output_toml):
+    assert rtoml.dumps(input_obj, omit_none=True) == output_toml

tests/test_load.py

@@ -222,3 +222,7 @@ def test_subtable():
 smooth = true
 """
     assert rtoml.loads(s) == ...
+
+
+def test_empty_toml():
+    assert rtoml.loads('') == {}