Struct ChatMessage 

pub struct ChatMessage {
    pub role: String,
    pub content: Option<MessageContent>,
    pub tool_calls: Option<Value>,
    pub extra: Map<String, Value>,
}

A chat message for transformation.

content uses MessageContent which accepts both a plain JSON string and a JSON array of content-part objects during deserialization, preserving the original form during serialization.

Lossless round-trip

transform_messages_for_capabilities is reached by deserializing a client’s messages array into this type and re-serializing the result, so any field this struct does not model would be deleted on the way through. Three fields are named because the transform reads them; everything else — tool_call_id, name, vendor extensions — is carried verbatim in extra and never interpreted.

This is not hypothetical tidiness. tool_call_id is required by the Jinja templates of exactly the models that set REQUIRES_STRICT_TURNS — the Mistral family — so dropping it would break tool calling on the models the transform exists to serve.

Fields

role: String

content: Option<MessageContent>

tool_calls: Option<Value>

extra: Map<String, Value>

Every other key the message carried, passed through untouched.

Flattened, so these sit at the message’s top level on the wire exactly where they came from. An empty map serializes to nothing.

Implementations

impl ChatMessage

fn merge_into(&mut self, other: Self)

Merge other into self in-place.

Used during strict-turn coalescing to combine consecutive same-role messages. Content is merged via MessageContent::merge_with; tool calls are concatenated as JSON arrays.

For extra the surviving message’s keys win and only absent ones are adopted from other. Only user / assistant messages are ever merged and those rarely carry extras, so this is a tie-break rule rather than a load-bearing one — but silently preferring the later message’s name over the one already in the merged text would be the surprising choice.

Trait Implementations

impl Clone for ChatMessage

fn clone(&self) -> ChatMessage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ChatMessage

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

Formats the value using the given formatter.

impl Default for ChatMessage

fn default() -> ChatMessage

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ChatMessage

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ChatMessage

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for ChatMessage

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for ChatMessage

impl StructuralPartialEq for ChatMessage