envseal 0.3.12

//! Security-signal taxonomy — the organizational backbone for every
//! threat detection in envseal.
//!
//! # The problem this solves
//!
//! Without a uniform signal model, every new heuristic forces three
//! changes in three places:
//!
//! 1. A field on [`super::GuiSecurityReport`] (or some sibling struct).
//! 2. A flag on [`crate::security_config::SecurityConfig`].
//! 3. A new branch in [`crate::gui::request_approval`].
//!
//! That doesn't scale past a few dozen detectors. With 100+
//! heuristics across screen recording, GUI threats, environment
//! injection, binary integrity, sandbox state, network posture, and
//! disk permissions, the approval logic becomes a tangle of
//! one-off `if` statements.
//!
//! # The model
//!
//! - Every detector emits zero or more [`Signal`]s.
//! - Every [`Signal`] is identified by a stable [`SignalId`]
//!   (`category.specific.modifier`, e.g. `gui.input_injector.xdotool`),
//!   carries a [`Category`] and a [`Severity`], and ships with
//!   human-readable label / description / mitigation strings.
//! - The [`Policy`] is a stable mapping from `(severity, security
//!   tier) → ` [`Action`]. The same Hostile signal blocks under
//!   Lockdown but only warns under Standard — that's a policy
//!   choice, not a detector choice.
//! - [`Action`] is what the approval pipeline consumes:
//!   ignore / log / warn (with optional friction) / block.
//!
//! # Adding a new detector
//!
//! 1. Append a new [`Category`] variant if needed (rare).
//! 2. Pick a stable `SignalId` like `disk.master_key.world_readable`.
//! 3. Implement detection in `core/src/guard/detectors/<category>.rs`
//!    (or an existing file), pushing [`Signal`]s into the assessor's
//!    accumulator.
//! 4. Declare the signal's default [`Severity`].
//!
//! That's it. No `request_approval` change, no `SecurityConfig`
//! field, no new branch in the `match` ladders. The policy decides
//! what to do — and the policy is a table, not code.

use crate::security_config::SecurityTier;

/// Stable, machine-readable identifier for a security signal.
///
/// Format: `<source>.<class>.<specific>` — for example
/// `gui.input_injector.xdotool`, `env.preload.ld_audit`,
/// `disk.master_key.world_readable`. Stability is part of the
/// contract: `SignalId`s appear in audit logs and external policy
/// configs, so renaming one is a breaking change.
///
/// Holds a `Cow` so most ids stay zero-allocation static literals
/// while detectors that interpolate a discovered tool/process name
/// (`gui.input_injector.{name}`) can build per-detection ids
/// without forcing every signal to allocate.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct SignalId(std::borrow::Cow<'static, str>);

impl SignalId {
    /// Construct a signal id from a `'static` literal — zero-cost.
    #[must_use]
    pub const fn new(id: &'static str) -> Self {
        Self(std::borrow::Cow::Borrowed(id))
    }

    /// Construct a signal id from a fully-qualified runtime string —
    /// used when loading user-authored policy overrides from
    /// `security.toml` where the id is read as a `String` rather
    /// than a literal. The string is taken verbatim; no
    /// sanitization is applied because the user is the trust
    /// boundary for their own config.
    #[must_use]
    pub fn from_runtime_string(id: &str) -> Self {
        Self(std::borrow::Cow::Owned(id.to_string()))
    }

    /// Construct a signal id by interpolating a runtime value into a
    /// taxonomic prefix, e.g. `SignalId::scoped("gui.input_injector",
    /// process_name)`. The id format remains `<prefix>.<scope>` so
    /// audit-log queries continue to work via prefix match.
    #[must_use]
    pub fn scoped(prefix: &'static str, scope: &str) -> Self {
        // Sanitize: scope must only contain `[a-z0-9_-]` so it
        // remains a valid taxonomic suffix and can't smuggle dots
        // (which would break `category.specific.modifier` parsers).
        let mut sanitized = String::with_capacity(scope.len());
        for ch in scope.chars() {
            if ch.is_ascii_alphanumeric() || ch == '_' || ch == '-' {
                sanitized.push(ch.to_ascii_lowercase());
            } else {
                sanitized.push('_');
            }
        }
        Self(std::borrow::Cow::Owned(format!("{prefix}.{sanitized}")))
    }

    /// The string form used in audit logs and external configs.
    #[must_use]
    pub fn as_str(&self) -> &str {
        &self.0
    }
}

impl std::fmt::Display for SignalId {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.0)
    }
}

/// What flavor of attack vector a signal represents. Categories are
/// stable: changing one breaks downstream consumers (audit log
/// analytics, external policy files). Adding a new variant is fine.
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
#[non_exhaustive]
pub enum Category {
    /// A process can synthesize keyboard / mouse events on the same
    /// session (`xdotool`, `ydotool`, `xte`, `wtype`, `AppleScript`
    /// `system events`, Windows `SendInput` automation tools).
    InputInjection,
    /// A process is recording the screen (OBS, ffmpeg + x11grab,
    /// `screencapture`, `Screen Recording` in Privacy & Security).
    ScreenRecording,
    /// Where the user is — local console, SSH session, X11
    /// forwarding, RDP/VNC. Changes whether GUI-only auth is even
    /// reachable.
    GuiPresence,
    /// Hostile dynamic-loader or interpreter env vars (`LD_PRELOAD`,
    /// `LD_AUDIT`, `LD_LIBRARY_PATH`, `DYLD_INSERT_LIBRARIES`,
    /// `PYTHONPATH`, `NODE_OPTIONS`).
    EnvironmentInjection,
    /// The target binary's hash doesn't match the policy entry — it
    /// has been replaced or modified since approval.
    BinaryIntegrity,
    /// A vault file has lax permissions (world-readable
    /// `master.key`, group-writable `policy.toml`, etc.).
    DiskPermissions,
    /// The vault was sealed by a different hardware backend than the
    /// one this device exposes. Cross-machine vault transfer attempt.
    DeviceMismatch,
    /// The append-only audit log could not be written.
    AuditFailure,
    /// The requested sandbox tier is unsupported / not applicable on
    /// this host (e.g. Lockdown on macOS without `sandbox_init`).
    SandboxUnavailable,
    /// Accessibility automation framework that could click approval
    /// buttons (AT-SPI bridge, macOS Accessibility API consumers).
    AccessibilityBridge,
    /// The target binary's *behavior* is risky regardless of integrity:
    /// it's a script interpreter (executes attacker-controlled scripts),
    /// or it lives in a user-writable / world-writable / Downloads-style
    /// directory where any process or social-engineered file drop could
    /// have planted it. Distinct from [`Self::BinaryIntegrity`] (which is
    /// hash-based) — a binary can pass integrity and still be risky.
    BinaryRisk,
    /// I/O context — how this process was launched. Stdin redirected
    /// from an actual pipe (FIFO), stdout going to a file an attacker
    /// can read, etc. Distinct from environment vars
    /// ([`Self::EnvironmentInjection`]) and binary identity
    /// ([`Self::BinaryIntegrity`] / [`Self::BinaryRisk`]).
    IoContext,
    /// The secret being stored fails an entropy check (looks like a
    /// dictionary word, has trivial structure, looks like a known
    /// test/demo placeholder, etc.).
    SecretQuality,
    /// The supervisor that wraps a child process saw the secret
    /// appear in the child's stdout/stderr. Indicates the secret was
    /// exfiltrated past envseal's control surface and had to be
    /// redacted.
    SupervisorLeak,
    /// Catch-all for signals that don't fit a defined category.
    Other,
}

impl Category {
    /// Stable string identifier used in audit logs and external
    /// policy configs.
    #[must_use]
    pub const fn as_str(&self) -> &'static str {
        match self {
            Self::InputInjection => "input_injection",
            Self::ScreenRecording => "screen_recording",
            Self::GuiPresence => "gui_presence",
            Self::EnvironmentInjection => "environment_injection",
            Self::BinaryIntegrity => "binary_integrity",
            Self::DiskPermissions => "disk_permissions",
            Self::DeviceMismatch => "device_mismatch",
            Self::AuditFailure => "audit_failure",
            Self::SandboxUnavailable => "sandbox_unavailable",
            Self::AccessibilityBridge => "accessibility_bridge",
            Self::BinaryRisk => "binary_risk",
            Self::IoContext => "io_context",
            Self::SecretQuality => "secret_quality",
            Self::SupervisorLeak => "supervisor_leak",
            Self::Other => "other",
        }
    }
}

/// Severity of a signal — the *intrinsic* threat level, before any
/// policy is applied. `Critical` always blocks; everything else is
/// policy-decided.
///
/// Severities have a total order: `Info < Warn < Degraded < Hostile
/// < Critical`. A policy that blocks `Hostile` implicitly blocks
/// `Critical`; a policy that warns on `Warn` does not warn on `Info`.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum Severity {
    /// Reportable but never blocks. Always logged at the audit
    /// layer, never surfaces a popup warning.
    Info,
    /// Surfaces a friction-free warning to the user (e.g., "screen
    /// recorder detected"). Approval can proceed.
    Warn,
    /// Tier policy may block. Standard tier proceeds with friction;
    /// Hardened/Lockdown block.
    Degraded,
    /// Strong block signal at Hardened+. Standard tier may still
    /// allow with explicit confirmation.
    Hostile,
    /// Always blocks regardless of tier — there is no scenario where
    /// proceeding is acceptable. Examples: `master.key` is a symlink
    /// pointing outside the vault root, audit log write failed.
    Critical,
}

impl Severity {
    /// Stable string identifier used in audit logs and external
    /// policy configs.
    #[must_use]
    pub const fn as_str(&self) -> &'static str {
        match self {
            Self::Info => "info",
            Self::Warn => "warn",
            Self::Degraded => "degraded",
            Self::Hostile => "hostile",
            Self::Critical => "critical",
        }
    }
}

/// One detected security signal at a point in time.
///
/// `Signal` is the unit of communication between detectors and the
/// approval pipeline. Detectors push signals; the policy layer
/// decides what to do with them; the approval pipeline acts on the
/// resulting [`Action`]s.
#[derive(Debug, Clone)]
pub struct Signal {
    /// Stable taxonomic id.
    pub id: SignalId,
    /// Category this signal belongs to.
    pub category: Category,
    /// Intrinsic severity (before policy is applied).
    pub severity: Severity,
    /// Short human-readable label for UI surfaces.
    pub label: &'static str,
    /// Per-detection contextual detail (process name, file path,
    /// hash mismatch values). Free-form so each detector can pass
    /// what's relevant.
    pub detail: String,
    /// One-sentence mitigation hint shown alongside the warning.
    pub mitigation: &'static str,
}

impl Signal {
    /// Construct a new signal.
    #[must_use]
    pub fn new(
        id: SignalId,
        category: Category,
        severity: Severity,
        label: &'static str,
        detail: impl Into<String>,
        mitigation: &'static str,
    ) -> Self {
        Self {
            id,
            category,
            severity,
            label,
            detail: detail.into(),
            mitigation,
        }
    }
}

/// What the policy layer decides for one signal under a given tier.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Action {
    /// Take no action. The signal is not even logged.
    Ignore,
    /// Log the signal to the audit trail. No user-facing surface.
    Log,
    /// Surface as a warning in the approval popup. If `friction` is
    /// `true`, require an additional challenge (e.g. typing a
    /// 4-digit code) before approval can complete.
    Warn {
        /// Whether the user must clear an additional challenge gate
        /// (numeric code) before the approval can proceed.
        friction: bool,
    },
    /// Block the operation outright. Approval cannot succeed; the
    /// caller receives an `Error::EnvironmentCompromised` (or
    /// equivalent) with the signal's `label` and `mitigation`.
    Block,
}

impl Action {
    /// Stable string identifier used in audit logs.
    #[must_use]
    pub const fn as_str(&self) -> &'static str {
        match self {
            Self::Ignore => "ignore",
            Self::Log => "log",
            Self::Warn { friction: false } => "warn",
            Self::Warn { friction: true } => "warn_with_challenge",
            Self::Block => "block",
        }
    }

    /// True if this action prevents the approval from completing.
    #[must_use]
    pub const fn blocks(&self) -> bool {
        matches!(self, Self::Block)
    }
}

/// The default policy: how each (severity, tier) pair maps to an
/// action.
///
/// The table is small, declarative, and deliberately conservative.
/// It can be overridden at runtime by [`Policy::override_action`]
/// for site-specific tightening (e.g., a corporate deployment that
/// wants `Warn` severity to block under Hardened).
///
/// # Default table
///
/// | Severity / Tier | Standard | Hardened | Lockdown |
/// |---|---|---|---|
/// | `Info`          | log      | log      | log      |
/// | `Warn`          | warn     | warn     | warn(F)  |
/// | `Degraded`      | warn(F)  | block    | block    |
/// | `Hostile`       | warn(F)  | block    | block    |
/// | `Critical`      | block    | block    | block    |
///
/// `warn(F)` = warn with friction (challenge gate).
#[derive(Debug, Clone, Default)]
pub struct Policy {
    /// Per-(severity, tier) overrides. Anything not in this map
    /// uses the default table baked into [`Policy::decide`].
    overrides: std::collections::HashMap<(Severity, SecurityTier), Action>,
    /// Per-signal-id overrides — strongest level of customization.
    /// A site that wants to mute a specific noisy detector (e.g.,
    /// `accessibility_bridge.at_spi_only`) does it here.
    per_signal: std::collections::HashMap<SignalId, Action>,
}

impl Policy {
    /// Construct an empty policy that uses defaults for every
    /// `(severity, tier)` pair.
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }

    /// Override the default action for one severity at one tier.
    pub fn override_action(&mut self, severity: Severity, tier: SecurityTier, action: Action) {
        self.overrides.insert((severity, tier), action);
    }

    /// Override the action for one specific signal id, regardless
    /// of tier or severity. Highest-priority override.
    pub fn override_signal(&mut self, id: SignalId, action: Action) {
        self.per_signal.insert(id, action);
    }

    /// Decide what to do about `signal` under the active `tier`.
    ///
    /// Order of resolution:
    /// 1. Per-signal-id override (strongest).
    /// 2. (severity, tier) override.
    /// 3. Default table.
    #[must_use]
    pub fn decide(&self, signal: &Signal, tier: SecurityTier) -> Action {
        let action = if let Some(action) = self.per_signal.get(&signal.id).copied() {
            action
        } else if let Some(action) = self.overrides.get(&(signal.severity, tier)).copied() {
            action
        } else {
            Self::default_action(signal.severity, tier)
        };
        // SECURITY: Critical-severity signals can never be silently
        // ignored, even if a user-authored override requests it.
        // This prevents a compromised config from disabling
        // always-block protections (e.g. master-key world-readable).
        if signal.severity == Severity::Critical && action == Action::Ignore {
            Action::Log
        } else {
            action
        }
    }

    /// The hard-coded default table — no overrides applied.
    ///
    /// Each `(severity, tier)` pair is listed explicitly even when
    /// distinct rows happen to produce the same [`Action`] today.
    /// That makes the policy auditable as a 5×3 matrix at a glance
    /// — see the table in this module's documentation. Future tier
    /// or severity additions land as new rows here, not as
    /// catch-all wildcards spread across the body.
    #[must_use]
    #[allow(clippy::match_same_arms)] // matrix readability beats DRY here
    pub const fn default_action(severity: Severity, tier: SecurityTier) -> Action {
        match (severity, tier) {
            (Severity::Info, _) => Action::Log,
            (Severity::Warn, SecurityTier::Standard | SecurityTier::Hardened) => {
                Action::Warn { friction: false }
            }
            (Severity::Warn, SecurityTier::Lockdown) => Action::Warn { friction: true },
            (Severity::Degraded, SecurityTier::Standard) => Action::Warn { friction: true },
            (Severity::Degraded, SecurityTier::Hardened | SecurityTier::Lockdown) => Action::Block,
            (Severity::Hostile, SecurityTier::Standard) => Action::Warn { friction: true },
            (Severity::Hostile, SecurityTier::Hardened | SecurityTier::Lockdown) => Action::Block,
            (Severity::Critical, _) => Action::Block,
        }
    }
}

/// Aggregate decision over a set of signals. Returned by
/// [`evaluate`] so the approval pipeline gets a single summary
/// rather than re-iterating over signals.
#[derive(Debug, Clone, Default)]
pub struct Decision {
    /// Whether any signal blocked.
    pub blocked: bool,
    /// Whether any signal demanded a challenge gate.
    pub needs_friction: bool,
    /// Human-facing warnings to surface in the approval popup. One
    /// entry per signal with `Action::Warn`.
    pub warnings: Vec<String>,
    /// First blocking signal, if any. Used to populate the error
    /// returned to the caller.
    pub blocking_signal: Option<Signal>,
    /// Every signal that was logged. Caller appends to audit.
    pub log_entries: Vec<Signal>,
}

/// Evaluate a slice of signals against the policy at a given tier
/// and produce a single decision.
#[must_use]
pub fn evaluate(signals: &[Signal], policy: &Policy, tier: SecurityTier) -> Decision {
    let mut decision = Decision::default();
    for signal in signals {
        match policy.decide(signal, tier) {
            Action::Ignore => {}
            Action::Log => decision.log_entries.push(signal.clone()),
            Action::Warn { friction } => {
                decision.warnings.push(format!(
                    "{}: {} — {}",
                    signal.label, signal.detail, signal.mitigation
                ));
                if friction {
                    decision.needs_friction = true;
                }
                decision.log_entries.push(signal.clone());
            }
            Action::Block => {
                decision.blocked = true;
                if decision.blocking_signal.is_none() {
                    decision.blocking_signal = Some(signal.clone());
                }
                decision.log_entries.push(signal.clone());
            }
        }
    }
    decision
}

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

    fn sig(severity: Severity) -> Signal {
        Signal::new(
            SignalId::new("test.signal.x"),
            Category::Other,
            severity,
            "test signal",
            "detail goes here",
            "fix it",
        )
    }

    #[test]
    fn default_policy_info_is_logged_at_every_tier() {
        for tier in [
            SecurityTier::Standard,
            SecurityTier::Hardened,
            SecurityTier::Lockdown,
        ] {
            assert_eq!(Policy::default_action(Severity::Info, tier), Action::Log);
        }
    }

    #[test]
    fn default_policy_critical_always_blocks() {
        for tier in [
            SecurityTier::Standard,
            SecurityTier::Hardened,
            SecurityTier::Lockdown,
        ] {
            assert_eq!(
                Policy::default_action(Severity::Critical, tier),
                Action::Block
            );
        }
    }

    #[test]
    fn default_policy_hostile_blocks_at_hardened_and_above() {
        assert_eq!(
            Policy::default_action(Severity::Hostile, SecurityTier::Hardened),
            Action::Block
        );
        assert_eq!(
            Policy::default_action(Severity::Hostile, SecurityTier::Lockdown),
            Action::Block
        );
        // Standard surfaces friction but does not block.
        match Policy::default_action(Severity::Hostile, SecurityTier::Standard) {
            Action::Warn { friction: true } => {}
            other => panic!("expected warn-with-friction, got {other:?}"),
        }
    }

    #[test]
    fn policy_per_signal_override_beats_severity_table() {
        let mut policy = Policy::new();
        let id = SignalId::new("specific.signal");
        policy.override_signal(id.clone(), Action::Ignore);
        // Hostile signals can be overridden to Ignore.
        let s = Signal::new(
            id.clone(),
            Category::Other,
            Severity::Hostile,
            "would-be-blocking signal",
            "",
            "",
        );
        assert_eq!(policy.decide(&s, SecurityTier::Lockdown), Action::Ignore);

        // Critical signals can NEVER be silently ignored, even with
        // a per-signal override — this prevents a compromised config
        // from disabling always-block protections.
        let crit = Signal::new(
            id,
            Category::Other,
            Severity::Critical,
            "would-be-blocking signal",
            "",
            "",
        );
        assert_eq!(policy.decide(&crit, SecurityTier::Lockdown), Action::Log);
    }

    #[test]
    fn policy_severity_tier_override_works() {
        let mut policy = Policy::new();
        // A site that wants to ignore Warn under Standard.
        policy.override_action(Severity::Warn, SecurityTier::Standard, Action::Ignore);
        let s = sig(Severity::Warn);
        assert_eq!(policy.decide(&s, SecurityTier::Standard), Action::Ignore);
        // Under Hardened the override doesn't apply.
        assert_eq!(
            policy.decide(&s, SecurityTier::Hardened),
            Action::Warn { friction: false }
        );
    }

    #[test]
    fn evaluate_aggregates_warnings_and_blocking() {
        let signals = [
            sig(Severity::Warn),
            sig(Severity::Hostile),
            sig(Severity::Info),
        ];
        let policy = Policy::new();
        let d = evaluate(&signals, &policy, SecurityTier::Lockdown);
        assert!(d.blocked, "Hostile under Lockdown must block");
        assert!(!d.warnings.is_empty(), "Warn must produce a user warning");
        assert_eq!(d.log_entries.len(), 3, "all 3 signals should be logged");
        assert!(d.blocking_signal.is_some());
    }

    #[test]
    fn scoped_signal_id_sanitizes_unsafe_chars() {
        // Tool names from /proc/<pid>/comm can contain anything;
        // SignalId must produce a clean taxonomic suffix.
        let id = SignalId::scoped("gui.input_injector", "xdotool");
        assert_eq!(id.as_str(), "gui.input_injector.xdotool");

        // Dots in scope must be replaced so the taxonomy doesn't
        // get extra levels we can't predict.
        let id = SignalId::scoped("env.preload", "LD_PRELOAD.evil.so");
        assert_eq!(id.as_str(), "env.preload.ld_preload_evil_so");

        // Spaces / slashes / unicode become `_`.
        let id = SignalId::scoped("gui.screen_recorder", "OBS Studio");
        assert_eq!(id.as_str(), "gui.screen_recorder.obs_studio");
    }

    #[test]
    fn scoped_signal_id_is_lowercased() {
        // Audit-log analytics rely on case-stable IDs.
        let id = SignalId::scoped("env.preload", "LD_PRELOAD");
        assert_eq!(id.as_str(), "env.preload.ld_preload");
    }

    #[test]
    fn per_signal_override_can_target_a_scoped_id() {
        // The whole point of granular ids: site can mute one
        // specific tool without muting the category.
        let mut policy = Policy::new();
        let xdotool_id = SignalId::scoped("gui.input_injector", "xdotool");
        let ydotool_id = SignalId::scoped("gui.input_injector", "ydotool");

        policy.override_signal(xdotool_id.clone(), Action::Ignore);

        let xdotool_signal = Signal::new(
            xdotool_id,
            Category::InputInjection,
            Severity::Hostile,
            "xdotool",
            "running",
            "stop it",
        );
        let ydotool_signal = Signal::new(
            ydotool_id,
            Category::InputInjection,
            Severity::Hostile,
            "ydotool",
            "running",
            "stop it",
        );

        // xdotool is muted; ydotool still hits the default action.
        assert_eq!(
            policy.decide(&xdotool_signal, SecurityTier::Lockdown),
            Action::Ignore
        );
        assert_eq!(
            policy.decide(&ydotool_signal, SecurityTier::Lockdown),
            Action::Block
        );
    }

    #[test]
    fn category_str_is_stable() {
        // A regression test for the stability contract — these
        // strings appear in audit logs.
        assert_eq!(Category::InputInjection.as_str(), "input_injection");
        assert_eq!(Category::ScreenRecording.as_str(), "screen_recording");
        assert_eq!(Category::DeviceMismatch.as_str(), "device_mismatch");
    }

    #[test]
    fn severity_ordering() {
        assert!(Severity::Info < Severity::Warn);
        assert!(Severity::Warn < Severity::Degraded);
        assert!(Severity::Degraded < Severity::Hostile);
        assert!(Severity::Hostile < Severity::Critical);
    }

    #[test]
    fn action_blocks_helper() {
        assert!(Action::Block.blocks());
        assert!(!Action::Warn { friction: true }.blocks());
        assert!(!Action::Log.blocks());
        assert!(!Action::Ignore.blocks());
    }

    #[test]
    fn empty_signals_yield_empty_decision() {
        let policy = Policy::new();
        let d = evaluate(&[], &policy, SecurityTier::Lockdown);
        assert!(!d.blocked);
        assert!(!d.needs_friction);
        assert!(d.warnings.is_empty());
        assert!(d.blocking_signal.is_none());
        assert!(d.log_entries.is_empty());
    }
}