Support serialization mode specification from model config and SerializationConfig

python/pydantic_core/_pydantic_core.pyi

@@ -355,6 +355,7 @@ def to_json(
     round_trip: bool = False,
     timedelta_mode: Literal['iso8601', 'float'] = 'iso8601',
     bytes_mode: Literal['utf8', 'base64'] = 'utf8',
+    inf_nan_mode: Literal['null', 'constants'] = 'constants',
     serialize_unknown: bool = False,
     fallback: Callable[[Any], Any] | None = None,
 ) -> bytes:
@@ -373,6 +374,7 @@ def to_json(
         round_trip: Whether to enable serialization and validation round-trip support.
         timedelta_mode: How to serialize `timedelta` objects, either `'iso8601'` or `'float'`.
         bytes_mode: How to serialize `bytes` objects, either `'utf8'` or `'base64'`.
+        inf_nan_mode: How to serialize `Infinity`, `-Infinity` and `NaN` values, either `'null'` or `'constants'`.
         serialize_unknown: Attempt to serialize unknown types, `str(value)` will be used, if that fails
             `"<Unserializable {value_type} object>"` will be used.
         fallback: A function to call when an unknown value is encountered,
@@ -414,6 +416,7 @@ def to_jsonable_python(
     round_trip: bool = False,
     timedelta_mode: Literal['iso8601', 'float'] = 'iso8601',
     bytes_mode: Literal['utf8', 'base64'] = 'utf8',
+    inf_nan_mode: Literal['null', 'constants'] = 'constants',
     serialize_unknown: bool = False,
     fallback: Callable[[Any], Any] | None = None,
 ) -> Any:
@@ -432,6 +435,7 @@ def to_jsonable_python(
         round_trip: Whether to enable serialization and validation round-trip support.
         timedelta_mode: How to serialize `timedelta` objects, either `'iso8601'` or `'float'`.
         bytes_mode: How to serialize `bytes` objects, either `'utf8'` or `'base64'`.
+        inf_nan_mode: How to serialize `Infinity`, `-Infinity` and `NaN` values, either `'null'` or `'constants'`.
         serialize_unknown: Attempt to serialize unknown types, `str(value)` will be used, if that fails
             `"<Unserializable {value_type} object>"` will be used.
         fallback: A function to call when an unknown value is encountered,

src/errors/validation_exception.rs

@@ -303,7 +303,7 @@ impl ValidationError {
         include_context: bool,
         include_input: bool,
     ) -> PyResult<&'py PyString> {
-        let state = SerializationState::new("iso8601", "utf8")?;
+        let state = SerializationState::new("iso8601", "utf8", "constants")?;
         let extra = state.extra(py, &SerMode::Json, true, false, false, true, None);
         let serializer = ValidationErrorSerializer {
             py,

src/serializers/config.rs

@@ -15,60 +15,98 @@ use crate::tools::SchemaDict;
 use super::errors::py_err_se_err;
 
 #[derive(Debug, Clone)]
+#[allow(clippy::struct_field_names)]
 pub(crate) struct SerializationConfig {
     pub timedelta_mode: TimedeltaMode,
     pub bytes_mode: BytesMode,
+    pub inf_nan_mode: InfNanMode,
 }
 
 impl SerializationConfig {
     pub fn from_config(config: Option<&PyDict>) -> PyResult<Self> {
         let timedelta_mode = TimedeltaMode::from_config(config)?;
         let bytes_mode = BytesMode::from_config(config)?;
+        let inf_nan_mode = InfNanMode::from_config(config)?;
         Ok(Self {
             timedelta_mode,
             bytes_mode,
+            inf_nan_mode,
         })
     }
 
-    pub fn from_args(timedelta_mode: &str, bytes_mode: &str) -> PyResult<Self> {
+    pub fn from_args(timedelta_mode: &str, bytes_mode: &str, inf_nan_mode: &str) -> PyResult<Self> {
         Ok(Self {
             timedelta_mode: TimedeltaMode::from_str(timedelta_mode)?,
             bytes_mode: BytesMode::from_str(bytes_mode)?,
+            inf_nan_mode: InfNanMode::from_str(inf_nan_mode)?,
         })
     }
 }
 
-#[derive(Default, Debug, Clone)]
-pub(crate) enum TimedeltaMode {
-    #[default]
-    Iso8601,
-    Float,
+pub trait FromConfig {
+    fn from_config(config: Option<&PyDict>) -> PyResult<Self>
+    where
+        Self: Sized;
 }
 
-impl FromStr for TimedeltaMode {
-    type Err = PyErr;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "iso8601" => Ok(Self::Iso8601),
-            "float" => Ok(Self::Float),
-            s => py_schema_err!(
-                "Invalid timedelta serialization mode: `{}`, expected `iso8601` or `float`",
-                s
-            ),
+macro_rules! serialization_mode {
+    ($name:ident, $config_key:expr, $($variant:ident => $value:expr),* $(,)?) => {
+        #[derive(Default, Debug, Clone, PartialEq, Eq)]
+        pub(crate) enum $name {
+            #[default]
+            $($variant,)*
         }
-    }
+
+        impl FromStr for $name {
+            type Err = PyErr;
+
+            fn from_str(s: &str) -> Result<Self, Self::Err> {
+                match s {
+                    $($value => Ok(Self::$variant),)*
+                    s => py_schema_err!(
+                        concat!("Invalid ", stringify!($name), " serialization mode: `{}`, expected ", $($value, " or "),*),
+                        s
+                    ),
+                }
+            }
+        }
+
+        impl FromConfig for $name {
+            fn from_config(config: Option<&PyDict>) -> PyResult<Self> {
+                let Some(config_dict) = config else {
+                    return Ok(Self::default());
+                };
+                let raw_mode = config_dict.get_as::<&str>(intern!(config_dict.py(), $config_key))?;
+                raw_mode.map_or_else(|| Ok(Self::default()), Self::from_str)
+            }
+        }
+
+    };
 }
 
-impl TimedeltaMode {
-    pub fn from_config(config: Option<&PyDict>) -> PyResult<Self> {
-        let Some(config_dict) = config else {
-            return Ok(Self::default());
-        };
-        let raw_mode = config_dict.get_as::<&str>(intern!(config_dict.py(), "ser_json_timedelta"))?;
-        raw_mode.map_or_else(|| Ok(Self::default()), Self::from_str)
-    }
+serialization_mode! {
+    TimedeltaMode,
+    "ser_json_timedelta",
+    Iso8601 => "iso8601",
+    Float => "float",
+}
+
+serialization_mode! {
+    BytesMode,
+    "ser_json_bytes",
+    Utf8 => "utf8",
+    Base64 => "base64",
+    Hex => "hex",
+}
+
+serialization_mode! {
+    InfNanMode,
+    "ser_json_inf_nan",
+    Null => "null",
+    Constants => "constants",
+}
 
+impl TimedeltaMode {
     fn total_seconds(py_timedelta: &PyDelta) -> PyResult<&PyAny> {
         py_timedelta.call_method0(intern!(py_timedelta.py(), "total_seconds"))
     }
@@ -124,39 +162,7 @@ impl TimedeltaMode {
     }
 }
 
-#[derive(Default, Debug, Clone)]
-pub(crate) enum BytesMode {
-    #[default]
-    Utf8,
-    Base64,
-    Hex,
-}
-
-impl FromStr for BytesMode {
-    type Err = PyErr;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "utf8" => Ok(Self::Utf8),
-            "base64" => Ok(Self::Base64),
-            "hex" => Ok(Self::Hex),
-            s => py_schema_err!(
-                "Invalid bytes serialization mode: `{}`, expected `utf8`, `base64` or `hex`",
-                s
-            ),
-        }
-    }
-}
-
 impl BytesMode {
-    pub fn from_config(config: Option<&PyDict>) -> PyResult<Self> {
-        let Some(config_dict) = config else {
-            return Ok(Self::default());
-        };
-        let raw_mode = config_dict.get_as::<&str>(intern!(config_dict.py(), "ser_json_bytes"))?;
-        raw_mode.map_or_else(|| Ok(Self::default()), Self::from_str)
-    }
-
     pub fn bytes_to_string<'py>(&self, py: Python, bytes: &'py [u8]) -> PyResult<Cow<'py, str>> {
         match self {
             Self::Utf8 => from_utf8(bytes)
@@ -190,28 +196,6 @@ pub fn utf8_py_error(py: Python, err: Utf8Error, data: &[u8]) -> PyErr {
     }
 }
 
-#[derive(Default, Debug, Clone, PartialEq, Eq)]
-pub(crate) enum InfNanMode {
-    #[default]
-    Null,
-    Constants,
-}
-
-impl FromStr for InfNanMode {
-    type Err = PyErr;
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        match s {
-            "null" => Ok(Self::Null),
-            "constants" => Ok(Self::Constants),
-            s => py_schema_err!(
-                "Invalid inf_nan serialization mode: `{}`, expected `null` or `constants`",
-                s
-            ),
-        }
-    }
-}
-
 impl FromPyObject<'_> for InfNanMode {
     fn extract(ob: &'_ PyAny) -> PyResult<Self> {
         let s = ob.extract::<&str>()?;

src/serializers/extra.rs

@@ -21,10 +21,10 @@ pub(crate) struct SerializationState {
 }
 
 impl SerializationState {
-    pub fn new(timedelta_mode: &str, bytes_mode: &str) -> PyResult<Self> {
+    pub fn new(timedelta_mode: &str, bytes_mode: &str, inf_nan_mode: &str) -> PyResult<Self> {
         let warnings = CollectWarnings::new(false);
         let rec_guard = SerRecursionGuard::default();
-        let config = SerializationConfig::from_args(timedelta_mode, bytes_mode)?;
+        let config = SerializationConfig::from_args(timedelta_mode, bytes_mode, inf_nan_mode)?;
         Ok(Self {
             warnings,
             rec_guard,

src/serializers/infer.rs

@@ -10,6 +10,7 @@ use pyo3::types::{
 use serde::ser::{Error, Serialize, SerializeMap, SerializeSeq, Serializer};
 
 use crate::input::{EitherTimedelta, Int};
+use crate::serializers::config::InfNanMode;
 use crate::serializers::errors::SERIALIZATION_ERR_MARKER;
 use crate::serializers::filter::SchemaFilter;
 use crate::serializers::shared::{PydanticSerializer, TypeSerializer};
@@ -120,10 +121,16 @@ pub(crate) fn infer_to_python_known(
     let value = match extra.mode {
         SerMode::Json => match ob_type {
             // `bool` and `None` can't be subclasses, `ObType::Int`, `ObType::Float`, `ObType::Str` refer to exact types
-            ObType::None | ObType::Bool | ObType::Int | ObType::Float | ObType::Str => value.into_py(py),
+            ObType::None | ObType::Bool | ObType::Int | ObType::Str => value.into_py(py),
             // have to do this to make sure subclasses of for example str are upcast to `str`
             ObType::IntSubclass => extract_i64(value)?.into_py(py),
-            ObType::FloatSubclass => value.extract::<f64>()?.into_py(py),
+            ObType::Float | ObType::FloatSubclass => {
+                let v = value.extract::<f64>()?;
+                if (v.is_nan() || v.is_infinite()) && extra.config.inf_nan_mode == InfNanMode::Null {
+                    return Ok(py.None());
+                }
+                v.into_py(py)
+            }
             ObType::Decimal => value.to_string().into_py(py),
             ObType::StrSubclass => value.extract::<&str>()?.into_py(py),
             ObType::Bytes => extra

src/serializers/mod.rs

@@ -213,7 +213,7 @@ impl SchemaSerializer {
 #[pyfunction]
 #[pyo3(signature = (value, *, indent = None, include = None, exclude = None, by_alias = true,
     exclude_none = false, round_trip = false, timedelta_mode = "iso8601", bytes_mode = "utf8",
-    serialize_unknown = false, fallback = None))]
+    inf_nan_mode = "constants", serialize_unknown = false, fallback = None))]
 pub fn to_json(
     py: Python,
     value: &PyAny,
@@ -225,10 +225,11 @@ pub fn to_json(
     round_trip: bool,
     timedelta_mode: &str,
     bytes_mode: &str,
+    inf_nan_mode: &str,
     serialize_unknown: bool,
     fallback: Option<&PyAny>,
 ) -> PyResult<PyObject> {
-    let state = SerializationState::new(timedelta_mode, bytes_mode)?;
+    let state = SerializationState::new(timedelta_mode, bytes_mode, inf_nan_mode)?;
     let extra = state.extra(
         py,
         &SerMode::Json,
@@ -248,7 +249,7 @@ pub fn to_json(
 #[allow(clippy::too_many_arguments)]
 #[pyfunction]
 #[pyo3(signature = (value, *, include = None, exclude = None, by_alias = true, exclude_none = false, round_trip = false,
-    timedelta_mode = "iso8601", bytes_mode = "utf8", serialize_unknown = false, fallback = None))]
+    timedelta_mode = "iso8601", bytes_mode = "utf8", inf_nan_mode = "constants", serialize_unknown = false, fallback = None))]
 pub fn to_jsonable_python(
     py: Python,
     value: &PyAny,
@@ -259,10 +260,11 @@ pub fn to_jsonable_python(
     round_trip: bool,
     timedelta_mode: &str,
     bytes_mode: &str,
+    inf_nan_mode: &str,
     serialize_unknown: bool,
     fallback: Option<&PyAny>,
 ) -> PyResult<PyObject> {
-    let state = SerializationState::new(timedelta_mode, bytes_mode)?;
+    let state = SerializationState::new(timedelta_mode, bytes_mode, inf_nan_mode)?;
     let extra = state.extra(
         py,
         &SerMode::Json,

src/serializers/type_serializers/bytes.rs

@@ -4,24 +4,28 @@ use pyo3::prelude::*;
 use pyo3::types::{PyBytes, PyDict};
 
 use crate::definitions::DefinitionsBuilder;
+use crate::serializers::config::{BytesMode, FromConfig};
 
 use super::{
     infer_json_key, infer_serialize, infer_to_python, BuildSerializer, CombinedSerializer, Extra, SerMode,
     TypeSerializer,
 };
 
 #[derive(Debug, Clone)]
-pub struct BytesSerializer;
+pub struct BytesSerializer {
+    bytes_mode: BytesMode,
+}
 
 impl BuildSerializer for BytesSerializer {
     const EXPECTED_TYPE: &'static str = "bytes";
 
     fn build(
         _schema: &PyDict,
-        _config: Option<&PyDict>,
+        config: Option<&PyDict>,
         _definitions: &mut DefinitionsBuilder<CombinedSerializer>,
     ) -> PyResult<CombinedSerializer> {
-        Ok(Self {}.into())
+        let bytes_mode = BytesMode::from_config(config)?;
+        Ok(Self { bytes_mode }.into())
     }
 }
 
@@ -38,8 +42,7 @@ impl TypeSerializer for BytesSerializer {
         let py = value.py();
         match value.downcast::<PyBytes>() {
             Ok(py_bytes) => match extra.mode {
-                SerMode::Json => extra
-                    .config
+                SerMode::Json => self
                     .bytes_mode
                     .bytes_to_string(py, py_bytes.as_bytes())
                     .map(|s| s.into_py(py)),
@@ -54,7 +57,7 @@ impl TypeSerializer for BytesSerializer {
 
     fn json_key<'py>(&self, key: &'py PyAny, extra: &Extra) -> PyResult<Cow<'py, str>> {
         match key.downcast::<PyBytes>() {
-            Ok(py_bytes) => extra.config.bytes_mode.bytes_to_string(key.py(), py_bytes.as_bytes()),
+            Ok(py_bytes) => self.bytes_mode.bytes_to_string(key.py(), py_bytes.as_bytes()),
             Err(_) => {
                 extra.warnings.on_fallback_py(self.get_name(), key, extra)?;
                 infer_json_key(key, extra)
@@ -71,7 +74,7 @@ impl TypeSerializer for BytesSerializer {
         extra: &Extra,
     ) -> Result<S::Ok, S::Error> {
         match value.downcast::<PyBytes>() {
-            Ok(py_bytes) => extra.config.bytes_mode.serialize_bytes(py_bytes.as_bytes(), serializer),
+            Ok(py_bytes) => self.bytes_mode.serialize_bytes(py_bytes.as_bytes(), serializer),
             Err(_) => {
                 extra.warnings.on_fallback_ser::<S>(self.get_name(), value, extra)?;
                 infer_serialize(value, serializer, include, exclude, extra)