tix/epics/

registry.rs

#[allow(clippy::wildcard_imports)]
use super::*;

/// The frontmatter key carrying an issue's epic references.
///
/// WP03's field is `epics` (contracts/epic-registry.md §3); named once here so a
/// second spelling has no home.
pub const EPICS_KEY: &str = "epics";

/// A derived reference to another epic, with its display label.
///
/// The label is computed on read and **never stored**: a stored name goes stale
/// the moment the epic is renamed (data-model §2).
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct EpicRef {
    /// The referenced epic's stable id.
    pub id: EpicId,
    /// The epic's display label at read time.
    pub name: String,
    /// `Name (e-id)`, from [`epic_display`].
    pub display: String,
}

impl EpicRef {
    /// Build a reference, deriving the label from the name.
    #[must_use]
    pub fn new(id: &EpicId, name: &str) -> Self {
        Self {
            id: id.clone(),
            name: name.to_string(),
            display: epic_display(id, name),
        }
    }
}

/// The service-side view of an epic (data-model §2).
///
/// Combines the registry record with the derived members and children.
/// Registry-only operations ([`create_epic`], [`edit_epic`]) return it with an
/// **empty** member list — there is no issue set to derive from — while
/// index-backed operations ([`EpicIndex::resolve`], [`list_epics`]) fill it.
/// Nothing here is stored.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Epic {
    /// The stable registry key; the identity that survives a rename (C-003).
    pub id: EpicId,
    /// The mutable display label; never the identity.
    pub name: String,
    /// Optional long-form context.
    pub description: Option<String>,
    /// Optional epic status (free-form; not a board column, not a category).
    pub status: Option<String>,
    /// Optional owner identity string.
    pub owner: Option<String>,
    /// Optional start date (`YYYY-MM-DD`).
    pub start_date: Option<String>,
    /// Optional due date (`YYYY-MM-DD`).
    pub due_date: Option<String>,
    /// Optional positive relative size, used by the epic rollup.
    pub weight: Option<i64>,
    /// The recorded parent epic **id**, exactly as stored. Retained even when it
    /// no longer resolves, so the reference can be repaired (contract §3.4).
    pub parent: Option<String>,
    /// Project **ids** this epic concerns, verbatim (FR-002).
    pub projects: Vec<String>,
    /// The recorded milestone **name**, verbatim (FR-002).
    pub milestone: Option<String>,
    /// The recorded cycle **name**, verbatim (FR-002).
    pub cycle: Option<String>,
    /// Derived members, ordered by issue number. Never stored.
    pub members: Vec<MemberRef>,
    /// `members.len()`, carried because listings ask for it constantly.
    pub member_count: usize,
    /// Derived child epics, in registry declaration order. Never stored.
    pub children: Vec<EpicRef>,
    /// `children.len()`.
    pub child_count: usize,
}

impl Epic {
    /// Project a registry record into the service view.
    pub(super) fn from_configuration(
        id: EpicId,
        record: &EpicConfiguration,
        members: Vec<MemberRef>,
        children: Vec<EpicRef>,
    ) -> Self {
        Self {
            id,
            name: record.name.clone(),
            description: record.description.clone(),
            status: record.status.clone(),
            owner: record.owner.clone(),
            start_date: record.start_date.clone(),
            due_date: record.due_date.clone(),
            weight: record.weight,
            parent: record.parent.clone(),
            projects: record.projects.clone(),
            milestone: record.milestone.clone(),
            cycle: record.cycle.clone(),
            member_count: members.len(),
            members,
            child_count: children.len(),
            children,
        }
    }
}

/// The shared display form for an epic: `Harden the sync path (e-7c4a91)`.
///
/// One function, because every listing must show the id beside the name and a
/// second formatting site is how two surfaces end up disagreeing about what an
/// epic is called.
#[must_use]
pub fn epic_display(id: &EpicId, name: &str) -> String {
    format!("{name} ({id})")
}

/// The diagnostic kinds the epic service names, spelled exactly.
///
/// The variants map one-to-one onto [`EpicError`], so a surface prints the named
/// kind without a second classification step (contract `cli-surface.md` §4).
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub enum EpicDiagnosticKind {
    /// A name is blank, padded, or already in use.
    DuplicateName,
    /// An epic reference names no stored epic.
    UnknownEpic,
    /// An issue selector names no issue in the snapshot.
    UnknownIssue,
    /// The start/due dates are malformed or inverted.
    InvalidDates,
    /// The weight is not a positive relative size.
    InvalidWeight,
    /// A reference field's value is not a well-formed id.
    InvalidReference,
    /// The proposed parent is the epic itself.
    SelfParent,
    /// The proposed parent chain would close a cycle.
    Cycle,
}

impl EpicDiagnosticKind {
    /// The canonical snake_case spelling a surface prints.
    #[must_use]
    pub fn as_str(self) -> &'static str {
        match self {
            EpicDiagnosticKind::DuplicateName => "duplicate_name",
            EpicDiagnosticKind::UnknownEpic => "unknown_epic",
            EpicDiagnosticKind::UnknownIssue => "unknown_issue",
            EpicDiagnosticKind::InvalidDates => "invalid_dates",
            EpicDiagnosticKind::InvalidWeight => "invalid_weight",
            EpicDiagnosticKind::InvalidReference => "invalid_reference",
            EpicDiagnosticKind::SelfParent => "self_parent",
            EpicDiagnosticKind::Cycle => "cycle",
        }
    }
}

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

/// The single wording for an epic reference that names no stored epic.
#[must_use]
pub fn unknown_epic_reason(reference: &str) -> String {
    format!("no epic matches `{reference}`; an epic is selected by its stable id or by name")
}

/// The single wording for an issue selector that names no issue.
#[must_use]
pub fn unknown_issue_reason(selector: impl fmt::Display) -> String {
    format!("issue `{selector}` is not in this store")
}

/// The single wording for an epic date refusal.
///
/// Wraps the shared [`crate::model::validate_issue_dates`] message so the date
/// *rule* keeps its one owner and only the wording lives here.
#[must_use]
pub fn invalid_dates_reason(detail: &str) -> String {
    format!("epic dates are invalid: {detail}")
}

/// The single wording for an epic weight refusal.
#[must_use]
pub fn invalid_weight_reason(value: i64) -> String {
    format!("epic weight must be a positive integer; got {value}")
}

/// The single wording for a reference field whose value is not a well-formed id.
///
/// The write-path half of WP01's load-time shape check: an epic references a
/// project **by id**, so a value that is not one has to be refused rather than
/// stored, or the registry would no longer load. A *dangling* but well-formed id
/// is a different thing and is stored, then diagnosed (C-005).
#[must_use]
pub fn invalid_reference_reason(field: &str, value: &str) -> String {
    format!(
        "`epics.<id>.{field}` entry `{value}` is not a well-formed id; \
         an epic references the target by its stable id"
    )
}

/// The single wording for an epic name refusal.
#[must_use]
pub fn duplicate_name_reason(name: &str) -> String {
    if name.trim().is_empty() {
        "an epic name must not be blank".to_string()
    } else if name.trim() != name {
        format!("epic name `{name}` has leading or trailing whitespace")
    } else {
        format!("epic name `{name}` is already in use; epic names must be unique")
    }
}

/// The single wording for a self-parent refusal.
#[must_use]
pub fn self_parent_reason(epic: &EpicId) -> String {
    format!("epic `{epic}` cannot be its own parent")
}

/// The single wording for a cycle refusal, naming the offending path.
#[must_use]
pub fn cycle_reason(epic: &EpicId, path: &[EpicId]) -> String {
    let rendered: Vec<&str> = path.iter().map(EpicId::as_str).collect();
    format!(
        "parent would close an epic cycle: `{epic}` -> {}",
        rendered.join(" -> ")
    )
}

/// The single wording for an unresolved parent epic (contract §3.4).
#[must_use]
pub fn unresolved_parent_reason(epic: &EpicId, recorded_parent: &str) -> String {
    format!(
        "epic `{epic}` records parent `{recorded_parent}`, which no longer exists \
         (the reference is kept so it can be repaired)"
    )
}

/// The single wording for a reference change's `## History` detail line.
///
/// One renderer, in the service, for every writer, so the CLI, the TUI and MCP
/// cannot word the same change differently.
#[must_use]
pub fn reference_detail(epic_id: &str, referenced: bool) -> String {
    if referenced {
        format!("epic `{epic_id}` referenced")
    } else {
        format!("epic `{epic_id}` dereferenced")
    }
}

/// Why an epic operation was refused.
///
/// The variants map one-to-one onto [`EpicDiagnosticKind`] and carry the
/// contract's names (`contracts/epic-service.md` §1).
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum EpicError {
    /// An epic reference did not resolve.
    UnknownEpic {
        /// The reference exactly as the caller wrote it.
        reference: String,
    },
    /// An issue selector named no issue in the snapshot.
    UnknownIssue {
        /// The selector exactly as the caller wrote it.
        selector: u32,
    },
    /// The name is blank, padded, or already in use.
    DuplicateName {
        /// The name as supplied.
        name: String,
    },
    /// The start/due dates are malformed or inverted.
    InvalidDates {
        /// The shared date rule's message.
        detail: String,
    },
    /// The weight is not a positive relative size.
    InvalidWeight {
        /// The value as supplied.
        value: i64,
    },
    /// A reference field's value is not a well-formed id.
    InvalidReference {
        /// The record field the value belongs to, e.g. `projects`.
        field: &'static str,
        /// The value as supplied.
        value: String,
    },
    /// The proposed parent is the epic itself.
    SelfParent {
        /// The epic that would parent itself.
        epic: EpicId,
    },
    /// The proposed parent chain would close a cycle.
    Cycle {
        /// The epic whose proposed parent closes the loop.
        epic: EpicId,
        /// The offending path, from the epic back to itself.
        path: Vec<EpicId>,
    },
}

impl EpicError {
    /// The named diagnostic kind this refusal reports.
    #[must_use]
    pub fn kind(&self) -> EpicDiagnosticKind {
        match self {
            EpicError::UnknownEpic { .. } => EpicDiagnosticKind::UnknownEpic,
            EpicError::UnknownIssue { .. } => EpicDiagnosticKind::UnknownIssue,
            EpicError::DuplicateName { .. } => EpicDiagnosticKind::DuplicateName,
            EpicError::InvalidDates { .. } => EpicDiagnosticKind::InvalidDates,
            EpicError::InvalidWeight { .. } => EpicDiagnosticKind::InvalidWeight,
            EpicError::InvalidReference { .. } => EpicDiagnosticKind::InvalidReference,
            EpicError::SelfParent { .. } => EpicDiagnosticKind::SelfParent,
            EpicError::Cycle { .. } => EpicDiagnosticKind::Cycle,
        }
    }

    /// The single wording for this refusal, via the kind's helper.
    #[must_use]
    pub fn message(&self) -> String {
        match self {
            EpicError::UnknownEpic { reference } => unknown_epic_reason(reference),
            EpicError::UnknownIssue { selector } => unknown_issue_reason(selector),
            EpicError::DuplicateName { name } => duplicate_name_reason(name),
            EpicError::InvalidDates { detail } => invalid_dates_reason(detail),
            EpicError::InvalidWeight { value } => invalid_weight_reason(*value),
            EpicError::InvalidReference { field, value } => invalid_reference_reason(field, value),
            EpicError::SelfParent { epic } => self_parent_reason(epic),
            EpicError::Cycle { epic, path } => cycle_reason(epic, path),
        }
    }
}

impl fmt::Display for EpicError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}: {}", self.kind(), self.message())
    }
}

impl std::error::Error for EpicError {}

/// An epic refusal becomes user input error, so `?` works at the call site.
///
/// The payload is a single-line diagnostic (`<kind>: <message>`), so it takes the
/// crate's existing `invalid input:` prefix without doubling it — the same
/// boundary every other selector/validation refusal crosses (cli-surface §6).
impl From<EpicError> for TixError {
    fn from(err: EpicError) -> TixError {
        TixError::InvalidInput(err.to_string())
    }
}

/// The spec for a new epic (contract §1: name plus optional metadata).
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct NewEpic {
    /// Required display label.
    pub name: String,
    /// Optional long-form context.
    pub description: Option<String>,
    /// Optional epic status.
    pub status: Option<String>,
    /// Optional owner identity string.
    pub owner: Option<String>,
    /// Optional start date.
    pub start_date: Option<String>,
    /// Optional due date.
    pub due_date: Option<String>,
    /// Optional positive relative size.
    pub weight: Option<i64>,
    /// Project **ids** this epic concerns (FR-002). Shape is checked; existence is
    /// diagnosed rather than refused, so a dangling reference is repairable.
    pub projects: Vec<String>,
    /// Optional milestone name (the existing name-keyed reference).
    pub milestone: Option<String>,
    /// Optional cycle name (the existing name-keyed reference).
    pub cycle: Option<String>,
}

/// The fields of an epic edit.
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct EpicEdit {
    /// The display label. A rename is a label change only (C-003, NFR-002).
    pub name: Patch<String>,
    /// Long-form context.
    pub description: Patch<String>,
    /// Epic status.
    pub status: Patch<String>,
    /// Owner identity string.
    pub owner: Patch<String>,
    /// Start date.
    pub start_date: Patch<String>,
    /// Due date.
    pub due_date: Patch<String>,
    /// Weight.
    pub weight: Patch<i64>,
    /// The parent epic reference: `Set` resolves to the parent's id and is
    /// validated against the epic chain, `Clear` detaches the epic.
    pub parent: Patch<String>,
    /// Project **ids** this epic concerns. Each entry is shape-validated and never
    /// resolved, so a dangling-but-well-formed id is stored for repair (C-005).
    pub projects: Patch<Vec<String>>,
    /// Milestone name; `Clear` removes the reference.
    pub milestone: Patch<String>,
    /// Cycle name; `Clear` removes the reference.
    pub cycle: Patch<String>,
}

/// The impact report of an epic deletion (contract §1).
///
/// It **reports**; it does not delete. The affected issues keep their references
/// (which then read as missing references, C-005) and the child epics keep their
/// recorded parent (which then reads as unresolved, contract §3.4), so this type
/// carries them for the caller's notice rather than a cascade (C-006).
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct EpicDeletion {
    /// The id that was removed from the registry. Never handed out again.
    pub id: EpicId,
    /// The name the record carried, for the notice.
    pub name: String,
    /// The issues that still reference the deleted epic, ordered by number.
    pub affected: Vec<MemberRef>,
    /// The epics that recorded it as their parent, in declaration order.
    pub child_epics: Vec<EpicRef>,
}

/// Normalize an optional text field: a written-but-empty value is absent.
///
/// WP01 refuses a present-but-blank key, so collapsing it here is what keeps a
/// record this service writes loadable. Non-blank values are kept verbatim.
pub(super) fn normalize_optional(value: Option<String>) -> Option<String> {
    value.filter(|v| !v.trim().is_empty())
}

/// Validate a requested display name against the registry.
///
/// Mirrors [`crate::config`]'s rule (`validate_epics`): non-blank, no padding,
/// and unique case-folded, since a user does not tell `Platform` from `platform`.
/// WP01 owns the loader's copy; this is the write-path half, pinned to the same
/// rule by `t006_create_epic_refuses_a_duplicate_name`.
pub(super) fn validate_name(
    registry: &IndexMap<String, EpicConfiguration>,
    name: &str,
    exclude: Option<&EpicId>,
) -> Result<(), EpicError> {
    if name.trim().is_empty() || name.trim() != name {
        return Err(EpicError::DuplicateName {
            name: name.to_string(),
        });
    }
    let normalized = name.to_lowercase();
    let clash = registry.iter().any(|(raw, record)| {
        let is_self = exclude.is_some_and(|id| raw.as_str() == id.as_str());
        !is_self && record.name.to_lowercase() == normalized
    });
    if clash {
        return Err(EpicError::DuplicateName {
            name: name.to_string(),
        });
    }
    Ok(())
}

/// Validate the pair through the shared date rule (WP01 uses the same helper).
pub(super) fn validate_dates(start: Option<&str>, due: Option<&str>) -> Result<(), EpicError> {
    crate::model::validate_issue_dates(start, due).map_err(|err| EpicError::InvalidDates {
        detail: err.to_string(),
    })
}

/// Validate a project-id list: shape only, never resolution.
///
/// Each entry must be a well-formed [`ProjectId`], because that is what a
/// registry must hold to load. A well-formed id the project registry does not
/// hold is **kept** — it is the diagnosable dangling reference C-005 promises —
/// and an exact duplicate collapses to one reference, as a repeated issue-side id
/// does. The caller's order is preserved.
pub(super) fn validate_project_ids(list: &[String]) -> Result<Vec<String>, EpicError> {
    let mut out: Vec<String> = Vec::new();
    for entry in list {
        let id = ProjectId::new(entry).map_err(|_| EpicError::InvalidReference {
            field: "projects",
            value: entry.clone(),
        })?;
        if !out.iter().any(|stored| stored == id.as_str()) {
            out.push(id.to_string());
        }
    }
    Ok(out)
}

/// Validate a weight: a positive relative size, or nothing.
pub(super) fn validate_weight(weight: i64) -> Result<(), EpicError> {
    if weight > 0 {
        return Ok(());
    }
    Err(EpicError::InvalidWeight { value: weight })
}

/// Resolve an epic id from a reference: **id first**, then a name convenience.
///
/// Resolution is by the stable id (C-003). A name is accepted because a human
/// selects epics by name; it resolves to the same epic, and WP01's uniqueness
/// rule guarantees it is unambiguous. An id that also happens to look like
/// another epic's name wins, which is what "id first" means.
pub fn resolve_epic_id(
    registry: &IndexMap<String, EpicConfiguration>,
    reference: &str,
) -> Result<EpicId, EpicError> {
    if let Ok(id) = EpicId::new(reference) {
        if registry.contains_key(id.as_str()) {
            return Ok(id);
        }
    }
    let normalized = reference.trim().to_lowercase();
    if let Some((raw, _)) = registry
        .iter()
        .find(|(_, record)| record.name.to_lowercase() == normalized)
    {
        return EpicId::new(raw).map_err(|_| EpicError::UnknownEpic {
            reference: reference.to_string(),
        });
    }
    Err(EpicError::UnknownEpic {
        reference: reference.to_string(),
    })
}

/// The epics that record `id` as their parent, in declaration order.
pub(super) fn recorded_children(
    registry: &IndexMap<String, EpicConfiguration>,
    id: &EpicId,
) -> Vec<EpicRef> {
    registry
        .iter()
        .filter(|(_, record)| record.parent.as_deref() == Some(id.as_str()))
        .filter_map(|(raw, record)| {
            EpicId::new(raw)
                .ok()
                .map(|child| EpicRef::new(&child, &record.name))
        })
        .collect()
}

/// Create an epic, allocating a fresh stable id (FR-001).
///
/// Validates the name, the dates, and the weight first, so a refusal yields no
/// registry change (contract §4). The record is inserted into the in-memory
/// [`Config`]; the caller persists it with `Config::save`, so the atomic write
/// path has exactly one owner. The returned view carries no members or children —
/// a create has no issue set to derive from.
pub fn create_epic(config: &mut Config, new: &NewEpic) -> Result<Epic, EpicError> {
    validate_name(&config.epics, &new.name, None)?;
    validate_dates(new.start_date.as_deref(), new.due_date.as_deref())?;
    if let Some(weight) = new.weight {
        validate_weight(weight)?;
    }
    let projects = validate_project_ids(&new.projects)?;
    let id = config.allocate_epic_id();
    let record = EpicConfiguration {
        name: new.name.clone(),
        description: normalize_optional(new.description.clone()),
        status: normalize_optional(new.status.clone()),
        owner: normalize_optional(new.owner.clone()),
        start_date: new.start_date.clone(),
        due_date: new.due_date.clone(),
        weight: new.weight,
        projects,
        milestone: normalize_optional(new.milestone.clone()),
        cycle: normalize_optional(new.cycle.clone()),
        ..EpicConfiguration::default()
    };
    config.epics.insert(id.to_string(), record.clone());
    Ok(Epic::from_configuration(
        id,
        &record,
        Vec::new(),
        Vec::new(),
    ))
}

/// Edit an epic's fields by reference.
///
/// A name change is a **label change only**: the registry key is untouched, so
/// every member reference and derived figure stays intact (C-003, NFR-002). A
/// proposed parent is validated — self-parent and cycle — **before** any write,
/// so a rejection leaves the registry byte-unchanged (contract §3, §4). The
/// returned view carries no members — an edit has no issue set to derive from.
pub fn edit_epic(config: &mut Config, reference: &str, edit: &EpicEdit) -> Result<Epic, EpicError> {
    let id = resolve_epic_id(&config.epics, reference)?;
    let mut updated =
        config
            .epics
            .get(id.as_str())
            .cloned()
            .ok_or_else(|| EpicError::UnknownEpic {
                reference: reference.to_string(),
            })?;

    // --- validation first: nothing below this block runs on a refusal --------
    match &edit.name {
        Patch::Unchanged => {}
        Patch::Clear => {
            return Err(EpicError::DuplicateName {
                name: String::new(),
            });
        }
        Patch::Set(name) => {
            validate_name(&config.epics, name, Some(&id))?;
        }
    }
    if let Patch::Set(weight) = &edit.weight {
        validate_weight(*weight)?;
    }
    let proposed_parent = match &edit.parent {
        Patch::Unchanged => None,
        Patch::Clear => Some(None),
        Patch::Set(parent) => Some(Some(validate_epic_parent(&config.epics, &id, parent)?)),
    };
    let proposed_projects = match &edit.projects {
        Patch::Unchanged => None,
        Patch::Clear => Some(Vec::new()),
        Patch::Set(list) => Some(validate_project_ids(list)?),
    };

    // --- apply --------------------------------------------------------------
    if let Patch::Set(name) = &edit.name {
        updated.name.clone_from(name);
    }
    apply_optional(&edit.description, &mut updated.description);
    apply_optional(&edit.status, &mut updated.status);
    apply_optional(&edit.owner, &mut updated.owner);
    apply_date(&edit.start_date, &mut updated.start_date);
    apply_date(&edit.due_date, &mut updated.due_date);
    if let Patch::Set(weight) = &edit.weight {
        updated.weight = Some(*weight);
    }
    if let Patch::Clear = &edit.weight {
        updated.weight = None;
    }
    if let Some(parent) = proposed_parent {
        updated.parent = parent.map(|id| id.to_string());
    }
    if let Some(projects) = proposed_projects {
        updated.projects = projects;
    }
    apply_optional(&edit.milestone, &mut updated.milestone);
    apply_optional(&edit.cycle, &mut updated.cycle);

    validate_dates(updated.start_date.as_deref(), updated.due_date.as_deref())?;

    if let Some(record) = config.epics.get_mut(id.as_str()) {
        *record = updated.clone();
    }
    Ok(Epic::from_configuration(
        id,
        &updated,
        Vec::new(),
        Vec::new(),
    ))
}

/// Apply an optional-text patch.
pub(super) fn apply_optional(patch: &Patch<String>, slot: &mut Option<String>) {
    match patch {
        Patch::Unchanged => {}
        Patch::Clear => *slot = None,
        Patch::Set(value) => *slot = normalize_optional(Some(value.clone())),
    }
}

/// Apply a date patch.
pub(super) fn apply_date(patch: &Patch<String>, slot: &mut Option<String>) {
    match patch {
        Patch::Unchanged => {}
        Patch::Clear => *slot = None,
        Patch::Set(value) => *slot = Some(value.clone()),
    }
}

/// Remove an epic from the registry, reporting what referenced it.
///
/// Removes the registry entry **only**. Every member issue keeps its `epics`
/// entry (which then reads as a missing reference) and every child epic keeps its
/// recorded parent (which then reads as unresolved), so both can be repaired
/// rather than being silently rebound (C-005, C-006). The id is never reused
/// (WP01's allocation carries that guarantee).
pub fn delete_epic<N: EpicNode>(
    config: &mut Config,
    reference: &str,
    issues: &[N],
) -> Result<EpicDeletion, EpicError> {
    let id = resolve_epic_id(&config.epics, reference)?;
    let record = config
        .epics
        .get(id.as_str())
        .cloned()
        .ok_or_else(|| EpicError::UnknownEpic {
            reference: reference.to_string(),
        })?;
    let affected = EpicIndex::build(config, issues)
        .epic(&id)
        .map(|epic| epic.members.clone())
        .unwrap_or_default();
    let child_epics = recorded_children(&config.epics, &id);
    config.epics.shift_remove(id.as_str());
    Ok(EpicDeletion {
        id,
        name: record.name,
        affected,
        child_epics,
    })
}