Method create

crates/opencode-session/src/compaction.rs:671–711

Create a compaction user message and compaction part. Mirrors TS `SessionCompaction.create`. Creates a user message with the given agent/model, then attaches a compaction part with the `auto` flag.

(
        input: CreateCompactionInput,
        session_ops: &S,
    )

    /// Mirrors TS `SessionCompaction.create`. Creates a user message with the
    /// given agent/model, then attaches a compaction part with the `auto` flag.
    pub async fn create<S: SessionOps>(
        input: CreateCompactionInput,
        session_ops: &S,
    ) -> anyhow::Result<(MessageInfo, Part)> {
        let msg_id = opencode_core::id::create(opencode_core::id::Prefix::Message, false, None);
        let now_ms = Utc::now().timestamp_millis();

        // TS: const msg = await Session.updateMessage({ role: "user", ... })
        let user_msg = MessageInfo::User {
            id: msg_id.clone(),
            session_id: input.session_id.clone(),
            time: UserTime { created: now_ms },
            agent: input.agent.clone(),
            model: input.model.clone(),
            format: None,
            summary: None,
            system: None,
            tools: None,
            variant: None,
        };
        let persisted_msg = session_ops.update_message(user_msg.clone()).await?;

        let persisted_id = match &persisted_msg {
            MessageInfo::User { id, .. } => id.clone(),
            MessageInfo::Assistant { id, .. } => id.clone(),
        };

        // TS: await Session.updatePart({ type: "compaction", auto: input.auto, ... })
        let part_id = opencode_core::id::create(opencode_core::id::Prefix::Part, false, None);
        let compaction_part = Part::Compaction(crate::message_v2::CompactionPart {
            id: part_id,
            session_id: input.session_id.clone(),
            message_id: persisted_id.clone(),
            auto: input.auto,
        });
        session_ops
            .update_part(&input.session_id, &persisted_id, compaction_part.clone())
            .await?;

        Ok((persisted_msg, compaction_part))
    }

    /// Prune tool results for a session using `SessionOps` for persistence.
    ///