bb_cli/commands/

update.rs

use crate::error::{BbError, Result};
use crate::output::{self, Format};
use serde::Deserialize;
use std::path::Path;
use std::time::Duration;

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum InstallKind {
    Homebrew,
    Cargo,
    Standalone,
}

/// Decides who owns the binary at `exe` from its path alone. Overwriting a
/// package-manager-owned file would leave brew or cargo believing it manages
/// a file it no longer controls, so those cases delegate instead.
pub fn classify_install(exe: &Path) -> InstallKind {
    let path = exe.to_string_lossy();
    if path.contains("/homebrew/") || path.contains("/Cellar/") || path.contains("/linuxbrew/") {
        return InstallKind::Homebrew;
    }
    if path.contains("/.cargo/bin/") {
        return InstallKind::Cargo;
    }
    InstallKind::Standalone
}

/// Parses `1.2.3` or `v1.2.3`. Returns `None` for anything else, including
/// four-component versions and pre-release suffixes.
pub fn parse_version(text: &str) -> Option<(u64, u64, u64)> {
    let trimmed = text.trim().trim_start_matches('v');
    let mut parts = trimmed.split('.');
    let major = parts.next()?.parse().ok()?;
    let minor = parts.next()?.parse().ok()?;
    let patch = parts.next()?.parse().ok()?;
    if parts.next().is_some() {
        return None;
    }
    Some((major, minor, patch))
}

/// True only when both versions parse and `latest` is strictly greater. An
/// unparseable remote tag is never an upgrade, so a malformed API response
/// cannot trigger a download.
pub fn is_newer(latest: &str, current: &str) -> bool {
    match (parse_version(latest), parse_version(current)) {
        (Some(l), Some(c)) => l > c,
        _ => false,
    }
}

/// The target triple of the running binary, or `None` on a platform this
/// project does not publish binaries for.
pub fn current_triple() -> Option<&'static str> {
    match (std::env::consts::OS, std::env::consts::ARCH) {
        ("macos", "aarch64") => Some("aarch64-apple-darwin"),
        ("macos", "x86_64") => Some("x86_64-apple-darwin"),
        ("linux", "x86_64") => Some("x86_64-unknown-linux-gnu"),
        ("linux", "aarch64") => Some("aarch64-unknown-linux-gnu"),
        _ => None,
    }
}

/// Archive and checksum asset names for a tag and triple. Must match the
/// `archive:` pattern in `.github/workflows/release.yml`, which is
/// `bbcloud-$tag-$target`; cargo-binstall's default templates key off the
/// crate name, which is why the prefix is `bbcloud` and not the binary name.
///
/// The checksum asset is named `<base>.sha256`, where `<base>` is the
/// archive name *without* its `.tar.gz` extension — not
/// `<archive>.tar.gz.sha256`. That's how `taiki-e/upload-rust-binary-action`
/// actually publishes it; verified against the real v0.9.0 release assets.
pub fn asset_names(tag: &str, triple: &str) -> (String, String) {
    let base = format!("bbcloud-{tag}-{triple}");
    let archive = format!("{base}.tar.gz");
    let checksum = format!("{base}.sha256");
    (archive, checksum)
}

pub const DEFAULT_RELEASE_API: &str = "https://api.github.com";

/// `brew upgrade bb` alone never fetches the tap, so a freshly published
/// formula stays invisible and reports "already installed" even when a
/// newer release exists. `brew update` (no arguments) is what refreshes it.
///
/// The formula is named in full, `biokraft/tap/bb`, rather than as bare `bb`.
/// Homebrew resolves an unqualified name against casks as well as formulae,
/// and an unrelated cask called `bb` now exists — so `brew upgrade bb` fails
/// with "Cask 'bb' is not installed" and never touches this install.
const HOMEBREW_UPDATE_HINT: &str = "brew update && brew upgrade biokraft/tap/bb";

/// The command that upgrades an install of this kind. A standalone install is
/// the only one `bb` can replace itself, so it is the only one pointed back at
/// `bb update`; the package-manager cases must go through their own manager or
/// brew and cargo would keep believing they manage a file they no longer wrote.
pub fn upgrade_hint(kind: InstallKind) -> &'static str {
    match kind {
        InstallKind::Homebrew => HOMEBREW_UPDATE_HINT,
        InstallKind::Cargo => "cargo install bbcloud --locked --force",
        InstallKind::Standalone => "bb update",
    }
}

/// The tag of the newest published release, e.g. `v0.19.4`.
///
/// Split out of `run` so the passive update check can ask the same question
/// with its own client — it needs a short timeout, since it runs ahead of a
/// command the user actually asked for, while `run` needs a long one because
/// it goes on to download a binary.
pub async fn latest_tag(http: &reqwest::Client, base_url: &str) -> Result<String> {
    Ok(latest_release(http, base_url).await?.tag_name)
}

async fn latest_release(http: &reqwest::Client, base_url: &str) -> Result<Release> {
    let url = format!(
        "{}/repos/biokraft/bbcloud/releases/latest",
        base_url.trim_end_matches('/')
    );
    let response = http.get(&url).send().await?;
    if !response.status().is_success() {
        return Err(release_error(&response));
    }
    let body = bound_body(response, MAX_RELEASE_JSON_BYTES, "release metadata").await?;
    Ok(serde_json::from_slice(&body)?)
}

#[derive(Debug, Deserialize)]
struct ReleaseAsset {
    name: String,
    browser_download_url: String,
}

#[derive(Debug, Deserialize)]
struct Release {
    tag_name: String,
    #[serde(default)]
    assets: Vec<ReleaseAsset>,
}

/// A client with no credentials attached. The Bitbucket `api::Client` always
/// sends the Basic auth header, and that token must never reach another host.
///
/// This client deliberately diverges from two of `api::Client`'s rules, and
/// both divergences are safe only because no credential is ever attached
/// here: redirects are followed (default policy) because GitHub asset
/// download URLs redirect to `objects.githubusercontent.com`, and the total
/// timeout is longer than the API client's because this transfers a compiled
/// binary rather than a JSON page.
fn release_client() -> Result<reqwest::Client> {
    Ok(reqwest::Client::builder()
        .connect_timeout(Duration::from_secs(10))
        .timeout(Duration::from_secs(120))
        .user_agent(concat!("bbcloud/", env!("CARGO_PKG_VERSION")))
        .build()?)
}

/// Archive downloads are capped generously for this binary but not
/// unbounded, so a checksum-valid bomb can't exhaust memory or disk. Enforced
/// while the body streams in (`fetch_bounded`), not after it is fully
/// buffered, since `Content-Length` is attacker-controlled and may be absent.
const MAX_ARCHIVE_BYTES: u64 = 64 * 1024 * 1024;
/// Decompressed output is capped separately: gzip can amplify a small
/// archive into a much larger stream.
const MAX_UNPACKED_BYTES: u64 = 200 * 1024 * 1024;
/// The `.sha256` body is a hex digest and a filename; a few KB is generous
/// and keeps a hostile checksum-file response from being buffered unbounded.
const MAX_CHECKSUM_BYTES: u64 = 4 * 1024;
/// The release metadata JSON (tag name plus asset list) is a few KB in
/// practice; 1 MiB is generous headroom while still keeping a hostile or
/// malformed response from being buffered unbounded via `response.json()`.
const MAX_RELEASE_JSON_BYTES: u64 = 1024 * 1024;

/// Downloads `url`'s body, rejecting it the moment the accumulated length
/// would exceed `limit` rather than after buffering the whole thing. A
/// `Content-Length` over the limit is rejected as a fast path, but is not
/// relied on alone since it is attacker-controlled and may be absent.
async fn fetch_bounded(
    http: &reqwest::Client,
    url: String,
    limit: u64,
    what: &str,
) -> Result<Vec<u8>> {
    let response = http.get(url).send().await?;
    bound_body(response, limit, what).await
}

/// The bounded-read half of `fetch_bounded`, split out so callers that must
/// inspect the response (e.g. its status code) before deciding to buffer the
/// body can still get the same length enforcement.
async fn bound_body(mut response: reqwest::Response, limit: u64, what: &str) -> Result<Vec<u8>> {
    if let Some(len) = response.content_length() {
        if len > limit {
            return Err(BbError::Config(format!(
                "{what} reports {len} bytes, larger than the {limit} byte limit"
            )));
        }
    }
    let mut buf = Vec::new();
    while let Some(chunk) = response.chunk().await? {
        buf.extend_from_slice(&chunk);
        if buf.len() as u64 > limit {
            return Err(BbError::Config(format!(
                "{what} exceeded the {limit} byte limit"
            )));
        }
    }
    Ok(buf)
}

pub fn release_api_base() -> String {
    std::env::var("BB_UPDATE_API_BASE").unwrap_or_else(|_| DEFAULT_RELEASE_API.to_string())
}

/// Header lookup that treats every header as optional: they only exist on
/// GitHub's responses, so any other host (or a malformed/missing header)
/// must fall through cleanly rather than panicking.
fn header_str<'a>(response: &'a reqwest::Response, name: &str) -> Option<&'a str> {
    response.headers().get(name)?.to_str().ok()
}

/// Renders a GitHub `x-ratelimit-reset` epoch as a local wall-clock
/// `HH:MM`. Returns `None` for a missing or unparseable header rather than
/// falling back to the Unix epoch (`1970-01-01`), which would be a lie.
fn retry_time(response: &reqwest::Response) -> Option<String> {
    let epoch: i64 = header_str(response, "x-ratelimit-reset")?.parse().ok()?;
    format_epoch_local(epoch)
}

/// Renders a Unix epoch as a local `HH:MM`, rejecting negative values rather
/// than letting them render as a pre-1970 clock.
fn format_epoch_local(epoch: i64) -> Option<String> {
    if epoch < 0 {
        return None;
    }
    let utc = chrono::DateTime::from_timestamp(epoch, 0)?;
    Some(
        utc.with_timezone(&chrono::Local)
            .format("%H:%M")
            .to_string(),
    )
}

/// Maps a non-success release-api response to an honest error: a GitHub
/// unauthenticated rate limit is named as such (with a retry time when the
/// header allows one), and anything else is reported as a plain release-api
/// error rather than a false "cannot reach" / "bitbucket" claim.
fn release_error(response: &reqwest::Response) -> BbError {
    let status = response.status();
    let remaining = header_str(response, "x-ratelimit-remaining");
    let is_rate_limited = matches!(status.as_u16(), 403 | 429) && remaining == Some("0");

    let message = if is_rate_limited {
        match retry_time(response) {
            Some(time) => format!(
                "github api rate limit reached — 60 requests per hour for unauthenticated access, retry after {time}"
            ),
            None => "github api rate limit reached — 60 requests per hour for unauthenticated access".to_string(),
        }
    } else {
        status
            .canonical_reason()
            .unwrap_or("unknown error")
            .to_string()
    };

    BbError::Release {
        status: status.as_u16(),
        message,
    }
}

pub async fn run(format: Format, base_url: &str) -> Result<()> {
    let current = env!("CARGO_PKG_VERSION");
    let http = release_client()?;
    let release = latest_release(&http, base_url).await?;
    let latest = release.tag_name.clone();

    let (action, up_to_date) = if !is_newer(&latest, current) {
        ("none", true)
    } else {
        let exe = std::env::current_exe().map_err(BbError::Io)?;
        let kind = classify_install(&exe);
        let action = match kind {
            InstallKind::Homebrew | InstallKind::Cargo => upgrade_hint(kind),
            InstallKind::Standalone => {
                // The https-only requirement below is scoped to real usage: it
                // only applies when the release api itself is https (the
                // production default). The `BB_UPDATE_API_BASE` test override
                // that points at a local http wiremock server also relaxes the
                // asset-url check, so integration tests can exercise the
                // download-and-unpack path without standing up TLS.
                let require_https = base_url.starts_with("https://");
                self_update(&http, &release, &exe, require_https).await?;
                "self-updated"
            }
        };
        (action, false)
    };

    // `brew upgrade bb` and `cargo install` never run our code, so this is the
    // only moment we can bring skill files up to date with the running binary.
    // Refreshing runs on every path `run()` can take, including up-to-date,
    // since that is the only path most Homebrew/Cargo users ever hit.
    let skill_outcomes = match crate::skill::refresh_tracked(crate::skill::MissingPolicy::Restore) {
        Ok(outcomes) => outcomes,
        // The binary upgrade already succeeded and is what the user actually
        // wanted; a filesystem problem here is a warning, not an exit code.
        Err(err) => {
            output::warn(&format!("could not refresh agent skills: {err}"));
            Vec::new()
        }
    };

    report(
        format,
        current,
        &latest,
        up_to_date,
        action,
        &skill_outcomes,
    )
}

fn report(
    format: Format,
    current: &str,
    latest: &str,
    up_to_date: bool,
    action: &str,
    skill_outcomes: &[crate::skill::Outcome],
) -> Result<()> {
    let refreshed: Vec<&crate::skill::Outcome> = skill_outcomes
        .iter()
        .filter(|o| o.action == crate::skill::Action::Refreshed)
        .collect();
    let skipped: Vec<&crate::skill::Outcome> = skill_outcomes
        .iter()
        .filter(|o| o.action == crate::skill::Action::SkippedModified)
        .collect();
    let pruned: Vec<&crate::skill::Outcome> = skill_outcomes
        .iter()
        .filter(|o| o.action == crate::skill::Action::Pruned)
        .collect();
    let failed: Vec<&crate::skill::Outcome> = skill_outcomes
        .iter()
        .filter(|o| o.action == crate::skill::Action::Failed)
        .collect();

    match format {
        Format::Json => {
            let mut payload = serde_json::json!({
                "current": current,
                "latest": latest,
                "up_to_date": up_to_date,
                "action": action,
            });
            if !skill_outcomes.is_empty() {
                payload["skills"] = serde_json::json!({
                    "refreshed": refreshed.len(),
                    "skipped_modified": skipped.iter().map(|o| &o.path).collect::<Vec<_>>(),
                    "pruned": pruned.iter().map(|o| &o.path).collect::<Vec<_>>(),
                    "failed": failed.iter().map(|o| &o.path).collect::<Vec<_>>(),
                });
            }
            output::print_json(&payload)
        }
        Format::Human => {
            if up_to_date {
                output::success(&format!("bb {current} is up to date"));
            } else {
                output::info(&format!("{current} -> {latest}"));
                if action == "self-updated" {
                    output::success("updated in place");
                } else {
                    output::info(&format!("this install is managed elsewhere; run: {action}"));
                }
            }
            if !refreshed.is_empty() {
                output::success(&format!(
                    "refreshed {} tracked agent skill{}",
                    refreshed.len(),
                    if refreshed.len() == 1 { "" } else { "s" }
                ));
            }
            for outcome in &skipped {
                output::info(&format!(
                    "skipped modified skill (customized locally): {}",
                    outcome.path.display()
                ));
            }
            // A skipped skill keeps the user's edits, which is the right
            // default — but it also means a release that added commands leaves
            // that agent describing a `bb` that no longer exists. Saying so
            // once, with the escape hatch, is the difference between a
            // protected file and a silently stale one.
            if !skipped.is_empty() {
                output::info(
                    "your edits are kept; run `bb skill install --force` to take the new version",
                );
            }
            for outcome in &pruned {
                output::info(&format!(
                    "forgot {} (directory no longer exists)",
                    outcome.path.display()
                ));
            }
            for outcome in &failed {
                output::warn(&format!(
                    "could not refresh {}: write failed",
                    outcome.path.display()
                ));
            }
            Ok(())
        }
    }
}

/// Removes the staged file on drop unless disarmed. This guarantees cleanup
/// on every early-return failure path after the file is created, not just
/// the one case that used to check for it.
struct StagedGuard {
    path: std::path::PathBuf,
    armed: bool,
}

impl StagedGuard {
    fn new(path: std::path::PathBuf) -> Self {
        Self { path, armed: true }
    }

    /// Call once the file has been successfully renamed into place, so drop
    /// does not try to remove a path that is now the live binary (or that no
    /// longer exists).
    fn disarm(mut self) {
        self.armed = false;
    }
}

impl Drop for StagedGuard {
    fn drop(&mut self) {
        if self.armed {
            let _ = std::fs::remove_file(&self.path);
        }
    }
}

/// The url comes from the release payload; a hijacked payload must not be
/// able to downgrade the transport used to fetch the binary. `require_https`
/// is false only for the `BB_UPDATE_API_BASE` test override, so production
/// use (the default `https://api.github.com`) always enforces this.
fn checked_asset_url(name: &str, url: String, require_https: bool) -> Result<String> {
    if require_https && !url.starts_with("https://") {
        return Err(BbError::Config(format!(
            "release asset {name} has a non-https download url"
        )));
    }
    Ok(url)
}

/// Downloads, verifies, unpacks and atomically replaces the running binary.
/// Nothing is written next to the binary until the digest matches.
async fn self_update(
    http: &reqwest::Client,
    release: &Release,
    exe: &Path,
    require_https: bool,
) -> Result<()> {
    let triple = current_triple()
        .ok_or_else(|| BbError::Config("no published binary for this platform".into()))?;
    let (archive_name, checksum_name) = asset_names(&release.tag_name, triple);

    let find = |name: &str| -> Result<String> {
        let url = release
            .assets
            .iter()
            .find(|a| a.name == name)
            .map(|a| a.browser_download_url.clone())
            .ok_or_else(|| BbError::Config(format!("release asset {name} is missing")))?;
        checked_asset_url(name, url, require_https)
    };

    let archive_bytes = fetch_bounded(
        http,
        find(&archive_name)?,
        MAX_ARCHIVE_BYTES,
        "release archive",
    )
    .await?;
    let checksum_bytes = fetch_bounded(
        http,
        find(&checksum_name)?,
        MAX_CHECKSUM_BYTES,
        "checksum file",
    )
    .await?;
    let expected = String::from_utf8_lossy(&checksum_bytes);
    let expected = expected
        .split_whitespace()
        .next()
        .unwrap_or_default()
        .to_lowercase();

    use sha2::{Digest, Sha256};
    let actual = format!("{:x}", Sha256::digest(&archive_bytes));
    if actual != expected {
        return Err(BbError::Config(
            "checksum mismatch — refusing to install this download".into(),
        ));
    }

    let parent = exe
        .parent()
        .ok_or_else(|| BbError::Config("cannot determine the install directory".into()))?;

    // Entropy in the name defeats a pre-planted symlink at a fixed path and
    // avoids two concurrent `bb update` runs colliding on the same file.
    let now = std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_nanos())
        .unwrap_or_default();
    let staged = parent.join(format!(".bb-update-staged-{}-{now}", std::process::id()));

    let mut found = false;
    let decoder = flate2::read::GzDecoder::new(std::io::Cursor::new(&archive_bytes[..]));
    let mut archive = tar::Archive::new(decoder);
    for entry in archive.entries()? {
        let mut entry = entry?;
        let is_bb = entry
            .path()?
            .file_name()
            .map(|n| n == std::ffi::OsStr::new("bb"))
            .unwrap_or(false);
        if !is_bb {
            continue;
        }
        // Do not let tar decide the node type. A symlink or hard-link entry
        // named `bb` must never be followed: `Entry::unpack` skips link
        // validation when given an explicit destination with no
        // `target_base`, which lets a malicious archive chmod or overwrite
        // an arbitrary file outside the install directory. Only a plain
        // regular file is accepted; anything else is treated as "not found".
        if !entry.header().entry_type().is_file() {
            continue;
        }

        // create_new(true) fails if the path already exists, which also
        // closes the pre-planted-file/symlink hole at the staged path.
        let mut out = std::fs::OpenOptions::new()
            .write(true)
            .create_new(true)
            .open(&staged)
            .map_err(BbError::Io)?;
        let guard = StagedGuard::new(staged.clone());

        let mut limited = std::io::Read::take(&mut entry, MAX_UNPACKED_BYTES);
        let copied = std::io::copy(&mut limited, &mut out).map_err(BbError::Io)?;
        drop(out);
        if copied >= MAX_UNPACKED_BYTES {
            return Err(BbError::Config(format!(
                "unpacked bb binary exceeds the {MAX_UNPACKED_BYTES} byte limit"
            )));
        }

        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;
            std::fs::set_permissions(&staged, std::fs::Permissions::from_mode(0o755))
                .map_err(BbError::Io)?;
        }

        // Same-directory rename is atomic, so an interrupted update can
        // never leave a truncated `bb` behind.
        std::fs::rename(&staged, exe).map_err(BbError::Io)?;
        guard.disarm();
        found = true;
        break;
    }
    if !found {
        return Err(BbError::Config(
            "archive contains no regular-file bb binary".into(),
        ));
    }
    Ok(())
}

#[cfg(test)]
#[allow(clippy::unwrap_used)]
mod tests {
    use super::*;
    use std::path::Path;

    #[test]
    fn homebrew_paths_are_detected() {
        for p in [
            "/opt/homebrew/bin/bb",
            "/usr/local/Cellar/bb/1.0.0/bin/bb",
            "/home/linuxbrew/.linuxbrew/bin/bb",
        ] {
            assert_eq!(classify_install(Path::new(p)), InstallKind::Homebrew, "{p}");
        }
    }

    /// `brew upgrade bb` alone does not refresh the tap, so a freshly
    /// published formula stays invisible; the hint must run `brew update`
    /// first. This exercises the same literal `run()` delegates to for a
    /// Homebrew install.
    #[test]
    fn homebrew_hint_refreshes_the_tap_before_upgrading() {
        assert_eq!(
            HOMEBREW_UPDATE_HINT,
            "brew update && brew upgrade biokraft/tap/bb"
        );
    }

    /// An unqualified `bb` is ambiguous to Homebrew, which resolves it
    /// against casks too and fails with "Cask 'bb' is not installed" — so the
    /// hint must name the tap. This is the bug the hint shipped with: the
    /// command it printed could not work.
    #[test]
    fn homebrew_hint_names_the_tap_so_the_formula_is_unambiguous() {
        assert!(
            HOMEBREW_UPDATE_HINT.contains("biokraft/tap/bb"),
            "hint must fully qualify the formula: {HOMEBREW_UPDATE_HINT}"
        );
        assert!(
            !HOMEBREW_UPDATE_HINT.contains("upgrade bb"),
            "hint must not upgrade an unqualified `bb`: {HOMEBREW_UPDATE_HINT}"
        );
    }

    #[test]
    fn cargo_bin_is_detected() {
        assert_eq!(
            classify_install(Path::new("/Users/dev/.cargo/bin/bb")),
            InstallKind::Cargo
        );
    }

    #[test]
    fn anything_else_is_standalone() {
        for p in ["/usr/local/bin/bb", "/home/dev/.local/bin/bb", "./bb"] {
            assert_eq!(
                classify_install(Path::new(p)),
                InstallKind::Standalone,
                "{p}"
            );
        }
    }

    #[test]
    fn versions_parse_with_and_without_a_v_prefix() {
        assert_eq!(parse_version("1.2.3"), Some((1, 2, 3)));
        assert_eq!(parse_version("v1.2.3"), Some((1, 2, 3)));
        assert_eq!(parse_version("v10.0.1"), Some((10, 0, 1)));
    }

    #[test]
    fn malformed_versions_are_rejected_rather_than_panicking() {
        for bad in ["", "v", "1.2", "1.2.x", "latest", "v1.2.3.4"] {
            assert_eq!(parse_version(bad), None, "{bad}");
        }
    }

    #[test]
    fn is_newer_compares_each_component() {
        assert!(is_newer("v1.0.1", "1.0.0"));
        assert!(is_newer("v1.1.0", "1.0.9"));
        assert!(is_newer("v2.0.0", "1.9.9"));
        assert!(!is_newer("v1.0.0", "1.0.0"));
        assert!(!is_newer("v0.9.0", "1.0.0"));
    }

    /// An unparseable remote tag must never be treated as an upgrade — that
    /// would download and install an arbitrary asset on a malformed response.
    #[test]
    fn unparseable_remote_tag_is_not_newer() {
        assert!(!is_newer("garbage", "1.0.0"));
        assert!(!is_newer("", "1.0.0"));
    }

    #[test]
    fn https_asset_urls_are_required_when_enforced() {
        assert!(
            checked_asset_url("bb.tar.gz", "http://evil.example/bb.tar.gz".into(), true).is_err()
        );
        assert!(
            checked_asset_url("bb.tar.gz", "https://example.com/bb.tar.gz".into(), true).is_ok()
        );
    }

    #[test]
    fn https_enforcement_is_skipped_for_the_test_override() {
        assert!(
            checked_asset_url("bb.tar.gz", "http://127.0.0.1:1234/bb.tar.gz".into(), false).is_ok()
        );
    }

    /// A negative epoch must never render a pre-1970 clock.
    #[test]
    fn negative_epoch_is_rejected() {
        assert_eq!(format_epoch_local(-1), None);
        assert_eq!(format_epoch_local(-1_000_000), None);
    }

    #[test]
    fn a_valid_epoch_still_formats() {
        assert!(format_epoch_local(1_786_452_151).is_some());
    }

    #[test]
    fn asset_names_follow_the_release_workflow_convention() {
        let (archive, checksum) = asset_names("v1.0.0", "x86_64-apple-darwin");
        assert_eq!(archive, "bbcloud-v1.0.0-x86_64-apple-darwin.tar.gz");
        assert_eq!(checksum, "bbcloud-v1.0.0-x86_64-apple-darwin.sha256");
    }
}