Struct AdditionalParams 

pub struct AdditionalParams(/* private fields */);

Provider extras on a content block: a non-empty JSON object, by construction.

The serialized form is the bare object (#[serde(transparent)]), so the wire shape of an additional_params field is a named key carrying an object — never flattened into the block’s own key namespace. The type carries the whole params contract, so no call-site convention is needed:

• Some(AdditionalParams) always carries data. The constructors collapse an empty map to None and the inner map is private, so emptiness checks on a params field are a plain is_none()/is_some() — no tolerant shim, in-tree or out.
• A non-object params value is unrepresentable in memory, so serialization can never emit a value deserialization rejects: what a live run writes, a restored run loads.
• On decode, null and {} canonicalize to an absent field (see optional_additional_params) and any other non-object value is a loud error.

The block structs themselves follow the complementary tolerance doctrine: a known field with the wrong shape is a loud decode error, an unknown key on a block is ignored (never captured, never replayed), and an unknown content-block tag is a loud error. The params are provider-specific: a serializer replays only params it recognizes as its own wire’s.

Implementations

impl AdditionalParams

pub fn new(map: Map<String, Value>) -> Option<AdditionalParams>

The canonical constructor: None when the map is empty.

pub fn from_entries<K, I>(entries: I) -> Option<AdditionalParams>

where K: Into<String>, I: IntoIterator<Item = (K, Value)>,

Build from (key, value) entries; None when the iterator yields none. Option<(K, Value)> is such an iterator, so a conditional single-key params reads as AdditionalParams::from_entries(guard.then(|| (key, value))).

pub fn get(&self, key: &str) -> Option<&Value>

The value stored under key, when present.

pub fn as_map(&self) -> &Map<String, Value>

The underlying (non-empty) object.

pub fn into_value(self) -> Value

The params as a bare JSON object value.

pub fn merge(&mut self, incoming: AdditionalParams)

Deep-merge incoming into self: arrays concatenate (streamed citation deltas), objects merge recursively, scalars take the incoming value.

pub fn wire_extras(&self, wire_key: &str) -> Option<&Map<String, Value>>

The extras stored under a wire’s own key, when present — the replay-side gate: a serializer asks for its key and never sees another wire’s extras (capture is unconditional at ingest; replay is gated here). A non-object value under the key yields None (it is not that wire’s extras); a caller that must distinguish malformed from absent — a warn path — pairs this with Self::get. Never a hard error: extras were written by a previous turn, and failing serialization over them would turn a persistence blemish into a broken conversation.

pub fn into_wire_extras(self, wire_key: &str) -> Option<Map<String, Value>>

Owned counterpart of Self::wire_extras for serialization paths that already own the params (the common replay case): extracts the wire’s object without cloning. Same gate semantics.

pub fn try_from_value(value: Value) -> Result<Option<AdditionalParams>, Value>

Build from a JSON value: Ok(None) for null and the empty object (canonical absence), Ok(Some) for a non-empty object, and Err handing the value back otherwise — a non-object is never silently swallowed; the caller decides loud versus lossy.

Trait Implementations

impl Clone for AdditionalParams

fn clone(&self) -> AdditionalParams

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AdditionalParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for AdditionalParams

fn deserialize<D>( deserializer: D, ) -> Result<AdditionalParams, <D as Deserializer<'de>>::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<AdditionalParams> for Value

fn from(params: AdditionalParams) -> Value

Converts to this type from the input type.

impl Index<&str> for AdditionalParams

fn index(&self, key: &str) -> &Value

Panics when the key is absent — the mirror of serde_json::Map’s Index, for test assertions and quick extraction.

type Output = Value

The returned type after indexing.

impl PartialEq for AdditionalParams

fn eq(&self, other: &AdditionalParams) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for AdditionalParams

fn serialize<__S>( &self, __serializer: __S, ) -> Result<<__S as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for AdditionalParams