ant-core 0.5.0

//! In-memory data operations using self-encryption.
//!
//! Upload and download raw byte data. Content is encrypted via
//! convergent encryption and stored as content-addressed chunks.
//! Use this when you already have data in memory (e.g., `Bytes`).
//! For file-based streaming uploads that avoid loading the entire
//! file into memory, see the `file` module.

use crate::data::client::adaptive::{observe_op, rebucketed_ordered};
use crate::data::client::batch::{PaymentIntent, PreparedChunk};
use crate::data::client::classify_error;
use crate::data::client::file::{ExternalPaymentInfo, PreparedUpload, Visibility};
use crate::data::client::merkle::{chunk_contents_for_upload_addresses, PaymentMode};
use crate::data::client::Client;
use crate::data::error::{Error, Result};
use ant_protocol::{compute_address, DATA_TYPE_CHUNK};
use bytes::Bytes;
use futures::stream::StreamExt;
use self_encryption::{decrypt, encrypt, get_root_data_map, DataMap, EncryptedChunk};
use std::num::NonZeroUsize;
use tokio::runtime::{Handle, RuntimeFlavor};
use tracing::{debug, info};
use xor_name::XorName;

/// Result of an in-memory data upload: the `DataMap` needed to retrieve the data.
#[derive(Debug, Clone)]
pub struct DataUploadResult {
    /// The data map containing chunk metadata for reconstruction.
    pub data_map: DataMap,
    /// Number of chunks stored on the network.
    pub chunks_stored: usize,
    /// Which payment mode was actually used (not just requested).
    pub payment_mode_used: PaymentMode,
}

impl Client {
    /// Upload in-memory data to the network using self-encryption.
    ///
    /// The content is encrypted and split into chunks, each stored
    /// as a content-addressed chunk on the network. Returns a `DataMap`
    /// that can be used to retrieve and decrypt the data.
    ///
    /// # Errors
    ///
    /// Returns an error if encryption fails or any chunk cannot be stored.
    pub async fn data_upload(&self, content: Bytes) -> Result<DataUploadResult> {
        let content_len = content.len();
        debug!("Encrypting data ({content_len} bytes)");

        let (data_map, encrypted_chunks) = encrypt(content)
            .map_err(|e| Error::Encryption(format!("Failed to encrypt data: {e}")))?;

        info!("Data encrypted into {} chunks", encrypted_chunks.len());

        let chunk_contents: Vec<Bytes> = encrypted_chunks
            .into_iter()
            .map(|chunk| chunk.content)
            .collect();

        let (addresses, _storage_cost, _gas_cost) =
            self.batch_upload_chunks(chunk_contents).await?;
        let chunks_stored = addresses.len();

        info!("Data uploaded: {chunks_stored} chunks stored ({content_len} bytes original)");

        Ok(DataUploadResult {
            data_map,
            chunks_stored,
            payment_mode_used: PaymentMode::Single,
        })
    }

    /// Upload in-memory data with a specific payment mode.
    ///
    /// When `mode` is `Auto` and the chunk count >= threshold, or when `mode`
    /// is `Merkle`, this buffers all chunks and pays via a single merkle
    /// batch transaction. Otherwise falls back to per-chunk payment.
    ///
    /// # Errors
    ///
    /// Returns an error if encryption fails or any chunk cannot be stored.
    pub async fn data_upload_with_mode(
        &self,
        content: Bytes,
        mode: PaymentMode,
    ) -> Result<DataUploadResult> {
        let content_len = content.len();
        debug!("Encrypting data ({content_len} bytes) with mode {mode:?}");

        let (data_map, encrypted_chunks) = encrypt(content)
            .map_err(|e| Error::Encryption(format!("Failed to encrypt data: {e}")))?;

        let chunk_count = encrypted_chunks.len();
        info!("Data encrypted into {chunk_count} chunks");

        let chunk_contents: Vec<Bytes> = encrypted_chunks
            .into_iter()
            .map(|chunk| chunk.content)
            .collect();

        if self.should_use_merkle(chunk_count, mode) {
            // Merkle batch payment path
            info!("Using merkle batch payment for {chunk_count} chunks");

            let chunk_entries: Vec<([u8; 32], u64)> = chunk_contents
                .iter()
                .map(|chunk| {
                    let size = u64::try_from(chunk.len())
                        .map_err(|e| Error::InvalidData(format!("chunk size too large: {e}")))?;
                    Ok((compute_address(chunk), size))
                })
                .collect::<Result<Vec<_>>>()?;
            let merkle_plan = match self
                .plan_merkle_upload(chunk_entries, DATA_TYPE_CHUNK, None)
                .await
            {
                Ok(plan) => plan,
                Err(Error::InsufficientPeers(ref msg)) if mode == PaymentMode::Auto => {
                    info!("Merkle preflight needs more peers ({msg}), falling back to wave-batch");
                    let (addresses, _sc, _gc) = self.batch_upload_chunks(chunk_contents).await?;
                    return Ok(DataUploadResult {
                        data_map,
                        chunks_stored: addresses.len(),
                        payment_mode_used: PaymentMode::Single,
                    });
                }
                Err(e) => return Err(e),
            };

            if merkle_plan.to_upload.is_empty() {
                info!("All {chunk_count} chunks already stored; skipping merkle payment");
                return Ok(DataUploadResult {
                    data_map,
                    chunks_stored: chunk_count,
                    payment_mode_used: PaymentMode::Merkle,
                });
            }

            let chunk_contents =
                chunk_contents_for_upload_addresses(chunk_contents, &merkle_plan.to_upload)?;

            let remaining_chunks = merkle_plan.to_upload.len();
            if !self.should_use_merkle(remaining_chunks, mode) {
                info!(
                    "{remaining_chunks} chunks need upload after merkle preflight; \
                     using single-node payment"
                );
                let (addresses, _sc, _gc) = self.batch_upload_chunks(chunk_contents).await?;
                return Ok(DataUploadResult {
                    data_map,
                    chunks_stored: merkle_plan.already_stored.len() + addresses.len(),
                    payment_mode_used: PaymentMode::Single,
                });
            }

            // Try merkle batch; in Auto mode, fall back to per-chunk on network issues
            let batch_result = match self
                .pay_for_merkle_batch(
                    &merkle_plan.to_upload,
                    DATA_TYPE_CHUNK,
                    merkle_plan.to_upload_avg_size(),
                )
                .await
            {
                Ok(result) => result,
                Err(Error::InsufficientPeers(ref msg)) if mode == PaymentMode::Auto => {
                    info!("Merkle needs more peers ({msg}), falling back to wave-batch");
                    let (addresses, _sc, _gc) = self.batch_upload_chunks(chunk_contents).await?;
                    return Ok(DataUploadResult {
                        data_map,
                        chunks_stored: merkle_plan.already_stored.len() + addresses.len(),
                        payment_mode_used: PaymentMode::Single,
                    });
                }
                Err(e) => return Err(e),
            };

            let outcome = self
                .merkle_upload_chunks(
                    chunk_contents,
                    merkle_plan.to_upload,
                    &batch_result,
                    None,
                    merkle_plan.already_stored.len(),
                    chunk_count,
                )
                .await?;
            // Unlike `FileUploadResult`, `DataUploadResult` cannot express a
            // partial store, and the returned `data_map` is unusable unless
            // every chunk landed (download fails on any missing chunk). So a
            // residual shortfall after retries is a hard failure here, not a
            // success with a quietly broken data map.
            if outcome.failed > 0 {
                return Err(Error::InsufficientPeers(format!(
                    "Data merkle upload incomplete: {} of {} chunk(s) short of quorum after retries",
                    outcome.failed, chunk_count
                )));
            }

            info!(
                "Data uploaded via merkle: {} chunks stored ({content_len} bytes)",
                outcome.stored
            );
            Ok(DataUploadResult {
                data_map,
                chunks_stored: outcome.stored,
                payment_mode_used: PaymentMode::Merkle,
            })
        } else {
            // Wave-based batch payment path (single EVM tx per wave).
            let (addresses, _sc, _gc) = self.batch_upload_chunks(chunk_contents).await?;

            info!(
                "Data uploaded: {} chunks stored ({content_len} bytes original)",
                addresses.len()
            );
            Ok(DataUploadResult {
                data_map,
                chunks_stored: addresses.len(),
                payment_mode_used: PaymentMode::Single,
            })
        }
    }

    /// Phase 1 of external-signer data upload: encrypt and collect quotes.
    ///
    /// Equivalent to [`Client::data_prepare_upload_with_visibility`] with
    /// [`Visibility::Private`] — see that method for details.
    pub async fn data_prepare_upload(&self, content: Bytes) -> Result<PreparedUpload> {
        self.data_prepare_upload_with_visibility(content, Visibility::Private)
            .await
    }

    /// Phase 1 of external-signer data upload with explicit [`Visibility`] control.
    ///
    /// Encrypts in-memory data via self-encryption, then collects storage
    /// quotes for each chunk without making any on-chain payment. Returns
    /// a [`PreparedUpload`] containing the data map and a [`PaymentIntent`]
    /// with the payment details for external signing.
    ///
    /// When `visibility` is [`Visibility::Public`], the serialized `DataMap`
    /// is bundled into the payment batch as an additional chunk and its
    /// address is recorded on the returned [`PreparedUpload`]. After
    /// [`Client::finalize_upload`] succeeds, that address is surfaced via
    /// [`crate::data::client::file::FileUploadResult::data_map_address`] so
    /// the uploader can share a single address from which anyone can retrieve
    /// the data.
    ///
    /// Wave-batch payment only — the in-memory data path does not currently
    /// support merkle batching. Use [`Client::file_prepare_upload_with_visibility`]
    /// for merkle-eligible public uploads.
    ///
    /// After the caller signs and submits the payment transaction, call
    /// [`Client::finalize_upload`] with the tx hashes to complete storage.
    ///
    /// # Errors
    ///
    /// Returns an error if encryption fails, DataMap serialization fails
    /// (public only), or quote collection fails.
    pub async fn data_prepare_upload_with_visibility(
        &self,
        content: Bytes,
        visibility: Visibility,
    ) -> Result<PreparedUpload> {
        let content_len = content.len();
        debug!("Preparing data upload for external signing (visibility={visibility:?}, {content_len} bytes)");

        let (data_map, encrypted_chunks) = encrypt(content)
            .map_err(|e| Error::Encryption(format!("Failed to encrypt data: {e}")))?;

        let mut chunk_contents: Vec<Bytes> = encrypted_chunks
            .into_iter()
            .map(|chunk| chunk.content)
            .collect();

        info!("Data encrypted into {} chunks", chunk_contents.len());

        // For public uploads, bundle the serialized DataMap as an extra chunk
        // in the same payment batch. This lets the external signer pay for
        // the data chunks and the DataMap chunk in one flow, and lets the
        // finalize step return the DataMap's chunk address as the shareable
        // retrieval address.
        let data_map_address = match visibility {
            Visibility::Private => None,
            Visibility::Public => {
                let serialized = rmp_serde::to_vec(&data_map).map_err(|e| {
                    Error::Serialization(format!("Failed to serialize DataMap: {e}"))
                })?;
                let bytes = Bytes::from(serialized);
                let address = compute_address(&bytes);
                info!(
                    "Public upload: bundling DataMap chunk ({} bytes) at address {}",
                    bytes.len(),
                    hex::encode(address)
                );
                chunk_contents.push(bytes);
                Some(address)
            }
        };

        let chunk_count = chunk_contents.len();
        let chunks_with_addr: Vec<(Bytes, [u8; 32])> = chunk_contents
            .into_iter()
            .map(|content| {
                let address = compute_address(&content);
                (content, address)
            })
            .collect();

        let quote_limiter = self.controller().quote.clone();
        let quote_concurrency = quote_limiter.current().min(chunk_count.max(1));
        let results: Vec<([u8; 32], Result<Option<PreparedChunk>>)> =
            futures::stream::iter(chunks_with_addr)
                .map(|(content, address)| {
                    let limiter = quote_limiter.clone();
                    async move {
                        let result = observe_op(
                            &limiter,
                            || async move { self.prepare_chunk_payment(content).await },
                            classify_error,
                        )
                        .await;
                        (address, result)
                    }
                })
                .buffer_unordered(quote_concurrency)
                .collect()
                .await;

        let mut prepared_chunks = Vec::with_capacity(results.len());
        let mut already_stored_addresses = Vec::new();
        for (address, result) in results {
            match result? {
                Some(prepared) => prepared_chunks.push(prepared),
                None => already_stored_addresses.push(address),
            }
        }

        if let Some(addr) = data_map_address {
            if already_stored_addresses.contains(&addr) {
                info!(
                    "Public upload: DataMap chunk {} was already stored \
                     on the network — address is retrievable without a \
                     new payment",
                    hex::encode(addr)
                );
            }
        }

        let payment_intent = PaymentIntent::from_prepared_chunks(&prepared_chunks);

        info!(
            "Data prepared for external signing: {} chunks, {} already stored, total {} atto ({content_len} bytes)",
            prepared_chunks.len(),
            already_stored_addresses.len(),
            payment_intent.total_amount,
        );

        Ok(PreparedUpload {
            data_map,
            payment_info: ExternalPaymentInfo::WaveBatch {
                prepared_chunks,
                payment_intent,
            },
            data_map_address,
            already_stored_addresses,
            total_chunks: chunk_count,
        })
    }

    /// Store a `DataMap` on the network as a public chunk.
    ///
    /// The serialized `DataMap` is stored as a regular content-addressed chunk.
    /// Anyone who knows the returned address can retrieve and use the `DataMap`
    /// to download the original data.
    ///
    /// # Errors
    ///
    /// Returns an error if serialization or the chunk store fails.
    pub async fn data_map_store(&self, data_map: &DataMap) -> Result<[u8; 32]> {
        let serialized = rmp_serde::to_vec(data_map)
            .map_err(|e| Error::Serialization(format!("Failed to serialize DataMap: {e}")))?;

        info!(
            "Storing DataMap as public chunk ({} bytes serialized)",
            serialized.len()
        );

        self.chunk_put(Bytes::from(serialized)).await
    }

    /// Fetch a `DataMap` from the network by its chunk address.
    ///
    /// Retrieves the chunk at `address` and deserializes it as a `DataMap`.
    ///
    /// # Errors
    ///
    /// Returns [`Error::NotFound`] if no chunk exists at `address`; other
    /// errors if retrieval or deserialization fails.
    pub async fn data_map_fetch(&self, address: &[u8; 32]) -> Result<DataMap> {
        let chunk = self.chunk_get(address).await?.ok_or_else(|| {
            Error::NotFound(format!(
                "DataMap chunk not found at {}",
                hex::encode(address)
            ))
        })?;

        decode_data_map_chunk(&chunk.content)
    }

    /// Fetch a `DataMap` from the network by trying the requested number
    /// of closest peers for the DataMap chunk.
    ///
    /// # Errors
    ///
    /// Returns [`Error::NotFound`] if no chunk exists at `address`; other
    /// errors if retrieval or deserialization fails.
    pub async fn data_map_fetch_from_closest_peers(
        &self,
        address: &[u8; 32],
        peer_count: NonZeroUsize,
    ) -> Result<DataMap> {
        let chunk = self
            .chunk_get_from_closest_peers(address, peer_count.get())
            .await?
            .ok_or_else(|| {
                Error::NotFound(format!(
                    "DataMap chunk not found at {}",
                    hex::encode(address)
                ))
            })?;

        decode_data_map_chunk(&chunk.content)
    }

    /// Download and decrypt data from the network using its `DataMap`.
    ///
    /// Retrieves all chunks referenced by the data map, then decrypts
    /// and reassembles the original content. Fetches chunks concurrently;
    /// the fan-out is sized by the adaptive controller's `fetch` channel
    /// and ramps up under healthy conditions.
    ///
    /// Large uploads produce a *shrunk* (child) `DataMap` whose `infos()`
    /// reference wrapper chunks rather than the root content chunks. Such a
    /// map is resolved back to its root form before download, keeping this
    /// primitive symmetric with `data_upload`.
    ///
    /// Resolving a shrunk map bridges self-encryption's synchronous fetcher
    /// onto the async network via `block_in_place`, so it requires a
    /// multi-threaded Tokio runtime; on a current-thread runtime it returns
    /// [`Error::Config`] instead of panicking. Flat maps (the common case)
    /// take neither path, so this requirement never applies to them.
    ///
    /// # Errors
    ///
    /// Returns an error if any chunk cannot be retrieved (a chunk absent from
    /// every queried peer surfaces as [`Error::NotFound`]), if decryption
    /// fails, or if a shrunk map must be resolved on a current-thread runtime.
    pub async fn data_download(&self, data_map: &DataMap) -> Result<Bytes> {
        let root_data_map = self.resolve_root_data_map(data_map).await?;

        let chunk_infos = root_data_map.infos();
        debug!("Downloading data ({} chunks)", chunk_infos.len());

        // Extract owned addresses to avoid HRTB lifetime issue with
        // stream::iter over references combined with async closures.
        let addresses: Vec<[u8; 32]> = chunk_infos.iter().map(|info| info.dst_hash.0).collect();

        // Rolling rebucketing: re-reads the controller's fetch cap as
        // each slot frees, so a long download (e.g. 10 GB = ~2500
        // chunks) sees adaptive growth/decay mid-flight without batch
        // fences. Output is index-sorted so self_encryption decrypt
        // sees DataMap-ordered chunks.
        let fetch_limiter = self.controller().fetch.clone();
        let encrypted_chunks: Vec<EncryptedChunk> = rebucketed_ordered(
            &fetch_limiter,
            addresses.into_iter().enumerate(),
            |(idx, address)| {
                async move {
                    // chunk_get_observed feeds the adaptive fetch
                    // limiter once per call via chunk_get_outcome
                    // (Ok(None) -> Timeout is the load-shedding
                    // signal for sustained close-group exhaustion).
                    let chunk = self.chunk_get_observed(&address).await?.ok_or_else(|| {
                        Error::NotFound(format!(
                            "Missing chunk {} required for data reconstruction",
                            hex::encode(address)
                        ))
                    })?;
                    Ok::<_, Error>((
                        idx,
                        EncryptedChunk {
                            content: chunk.content,
                        },
                    ))
                }
            },
        )
        .await?;

        debug!(
            "All {} chunks retrieved, decrypting",
            encrypted_chunks.len()
        );

        let content = decrypt(&root_data_map, &encrypted_chunks)
            .map_err(|e| Error::Encryption(format!("Failed to decrypt data: {e}")))?;

        info!("Data downloaded and decrypted ({} bytes)", content.len());

        Ok(content)
    }

    /// Resolve a possibly-shrunk `DataMap` to its root (flat) form.
    ///
    /// `data_upload` shrinks large maps via self-encryption's
    /// `shrink_data_map`: the serialized map is recursively encrypted into
    /// wrapper chunks (which are uploaded alongside the content chunks) and
    /// the returned map has `is_child() == true`. Its `infos()` reference the
    /// outermost wrapper chunks, *not* the root content chunks, so handing it
    /// straight to `decrypt` fails with a missing-chunk error for a root-level
    /// chunk that was never fetched.
    ///
    /// This fetches the wrapper chunks and unshrinks recursively (via
    /// `self_encryption::get_root_data_map`) until it obtains the root map,
    /// whose `infos()` reference the actual content chunks. A map that is not
    /// a child is returned unchanged without any network access.
    ///
    /// Resolution bridges self-encryption's synchronous fetcher onto the async
    /// network via `block_in_place`, which requires a multi-threaded Tokio
    /// runtime. On a current-thread runtime this returns [`Error::Config`]
    /// rather than letting `block_in_place` panic.
    ///
    /// # Errors
    ///
    /// Returns an error if called on a current-thread runtime, if a wrapper
    /// chunk cannot be retrieved, or if the map cannot be unshrunk.
    async fn resolve_root_data_map(&self, data_map: &DataMap) -> Result<DataMap> {
        if !data_map.is_child() {
            return Ok(data_map.clone());
        }

        debug!("DataMap is shrunk (child); resolving root data map");

        // `get_root_data_map` drives a synchronous `FnMut` fetcher, so bridge
        // to the async `chunk_get_observed` via `block_in_place` + `block_on`
        // (the same pattern `file_download` uses). The observed variant feeds
        // the adaptive fetch limiter, keeping the wrapper-chunk fetches
        // consistent with the content-chunk fetches in `data_download`.
        // `block_in_place` panics on a current-thread runtime, so reject that
        // precondition with a clear error instead of letting it panic inside
        // the fetcher.
        let handle = Handle::current();
        ensure_shrunk_resolution_runtime(handle.runtime_flavor())?;

        // The self-encryption fetcher may only yield `self_encryption::Error`.
        // Capture the underlying `ant-core` error out-of-band so a missing
        // wrapper chunk surfaces as `Error::NotFound` (matching the
        // content-chunk path) and a network failure keeps its `Timeout` /
        // `Network` classification, instead of every resolution failure
        // flattening to `Error::Encryption`.
        let mut fetch_error: Option<Error> = None;
        let resolve_result = tokio::task::block_in_place(|| {
            let mut get_chunk =
                |name: XorName| -> std::result::Result<Bytes, self_encryption::Error> {
                    let address = name.0;
                    handle.block_on(async {
                        match self.chunk_get_observed(&address).await {
                            Ok(Some(chunk)) => Ok(chunk.content),
                            Ok(None) => Err(record_wrapper_fetch_error(
                                &mut fetch_error,
                                Error::NotFound(format!(
                                    "Missing wrapper chunk {} required to resolve root DataMap",
                                    hex::encode(address)
                                )),
                            )),
                            Err(e) => Err(record_wrapper_fetch_error(&mut fetch_error, e)),
                        }
                    })
                };
            get_root_data_map(data_map.clone(), &mut get_chunk)
        });

        resolve_result.map_err(|e| {
            fetch_error.take().unwrap_or_else(|| {
                Error::Encryption(format!("Failed to resolve root data map: {e}"))
            })
        })
    }
}

/// Stash the real `ant-core` error behind a self-encryption fetch failure and
/// return the `self_encryption::Error` the fetcher is required to yield.
///
/// `get_root_data_map`'s fetcher may only return `self_encryption::Error`, which
/// would otherwise flatten a missing chunk or a classified network error into a
/// generic `Error::Encryption`. Recording the descriptive error in `slot` lets
/// [`Client::resolve_root_data_map`] recover it and preserve the error taxonomy.
fn record_wrapper_fetch_error(slot: &mut Option<Error>, error: Error) -> self_encryption::Error {
    let message = error.to_string();
    *slot = Some(error);
    self_encryption::Error::Generic(message)
}

/// Reject resolving a shrunk `DataMap` on a current-thread Tokio runtime.
///
/// Resolution uses `block_in_place` to bridge self-encryption's synchronous
/// chunk fetcher onto the async network, and `block_in_place` panics on a
/// current-thread runtime. Mapping that precondition to [`Error::Config`]
/// turns a hard panic into a recoverable error for library consumers that
/// drive `data_download` from a current-thread runtime.
fn ensure_shrunk_resolution_runtime(flavor: RuntimeFlavor) -> Result<()> {
    if flavor == RuntimeFlavor::CurrentThread {
        return Err(Error::Config(
            "resolving a shrunk DataMap requires a multi-threaded Tokio runtime, \
             but data_download was called on a current-thread runtime"
                .to_string(),
        ));
    }
    Ok(())
}

fn decode_data_map_chunk(content: &[u8]) -> Result<DataMap> {
    rmp_serde::from_slice(content)
        .map_err(|e| Error::Serialization(format!("Failed to deserialize DataMap: {e}")))
}

/// Compile-time assertions that Client method futures are Send.
///
/// These methods are called from axum handlers and tokio::spawn contexts
/// that require Send + 'static. The async closures inside stream
/// combinators must not capture references with concrete lifetimes
/// (HRTB issue). If any of these checks fail, the stream closures
/// need restructuring to use owned values instead of references.
#[cfg(test)]
mod send_assertions {
    use super::*;

    fn _assert_send<T: Send>(_: &T) {}

    #[allow(
        dead_code,
        unreachable_code,
        unused_variables,
        clippy::diverging_sub_expression
    )]
    async fn _data_download_is_send(client: &Client) {
        let dm: DataMap = todo!();
        let fut = client.data_download(&dm);
        _assert_send(&fut);
    }

    #[allow(dead_code, unreachable_code, clippy::diverging_sub_expression)]
    async fn _data_upload_is_send(client: &Client) {
        let fut = client.data_upload(Bytes::new());
        _assert_send(&fut);
    }

    #[allow(dead_code, unreachable_code, clippy::diverging_sub_expression)]
    async fn _data_upload_with_mode_is_send(client: &Client) {
        let fut = client.data_upload_with_mode(Bytes::new(), PaymentMode::Auto);
        _assert_send(&fut);
    }

    #[allow(dead_code, unreachable_code, clippy::diverging_sub_expression)]
    async fn _data_prepare_upload_is_send(client: &Client) {
        let fut = client.data_prepare_upload(Bytes::new());
        _assert_send(&fut);
    }

    #[allow(dead_code, unreachable_code, clippy::diverging_sub_expression)]
    async fn _data_prepare_upload_with_visibility_is_send(client: &Client) {
        let fut = client.data_prepare_upload_with_visibility(Bytes::new(), Visibility::Public);
        _assert_send(&fut);
    }
}

#[cfg(test)]
mod runtime_guard_tests {
    use super::*;

    #[test]
    fn shrunk_resolution_rejects_current_thread_runtime() {
        // A current-thread runtime cannot drive `block_in_place`, so the guard
        // must surface a descriptive `Error::Config` rather than panicking.
        assert!(matches!(
            ensure_shrunk_resolution_runtime(RuntimeFlavor::CurrentThread),
            Err(Error::Config(_))
        ));
    }

    #[test]
    fn shrunk_resolution_accepts_multi_thread_runtime() {
        assert!(ensure_shrunk_resolution_runtime(RuntimeFlavor::MultiThread).is_ok());
    }
}