herogpui_components/

validation.rs

//! The shared `validate` / `validationErrors` model.
//!
//! v3's `validate` is a function the *component* runs: it receives the current
//! value and returns either nothing or a message to display. Treating it as
//! "the caller validates and passes `isInvalid`" loses that — the component
//! never runs anything and the prop does not exist. This module is the shape
//! every field uses instead, so the eight components that document `validate`
//! behave identically.

use std::collections::BTreeMap;
use std::sync::atomic::{AtomicU64, Ordering};
use std::sync::Arc;

use gpui::SharedString;

/// Mints record identity: every *constructed or rebuilt* [`ValidationErrors`]
/// is a new server response, while a `clone` keeps the revision it was copied
/// from. Structural equality cannot carry this — a re-sent response can be
/// content-equal to the old one and must still re-arm.
static NEXT_RECORD_REVISION: AtomicU64 = AtomicU64::new(1);

fn next_record_revision() -> u64 {
    NEXT_RECORD_REVISION.fetch_add(1, Ordering::Relaxed)
}

/// HeroUI v3's `ValidationErrors` — `Record<string, string | string[]>`, the
/// server-side errors [`Form`](crate::form::Form) maps by field name.
///
/// The record is a *name-keyed mapping*, not a message list: the form routes
/// each entry into the named field's own error slot, never into a form-level
/// stack. Names the fields do not register display nowhere and block nothing.
///
/// Identity is part of the contract. Delivery is keyed to [`Self::revision`],
/// not to equality:
///
/// - a `clone` keeps its revision, so re-rendering with the same record never
///   resurrects a message the user edited away;
/// - any freshly built record — [`new`](Self::new), [`default`](Default::default)
///   or [`set`](Self::set) — mints a new revision and re-arms every named
///   field, even when the content equals the old record (a server that
///   re-sends the same error is a new response, not silence).
///
/// The caller half of that contract: *retain one record for as long as a
/// response is current* — in app state, a `thread_local`, wherever the frame
/// rebuilds from — and hand the form a [`Clone`] of it every frame.
/// Constructing a fresh record per frame (`ValidationErrors::new()`, or
/// re-running the builder chain in `render`) is a brand-new server response
/// every frame and re-arms every named field every frame, however equal the
/// content looks. This is exactly React Stately's reference identity: what
/// re-arms is a *new record*, never a re-sent one.
///
/// [`PartialEq`] compares content only, so records can be compared while the
/// identity stays a separate, explicit question.
#[derive(Clone, Debug)]
pub struct ValidationErrors {
    revision: u64,
    entries: BTreeMap<SharedString, Vec<SharedString>>,
}

impl ValidationErrors {
    /// A new, empty record: a fresh server response.
    pub fn new() -> Self {
        Self {
            revision: next_record_revision(),
            entries: BTreeMap::new(),
        }
    }

    /// The record's identity. Two records with equal content but different
    /// revisions are two different responses; a clone shares the revision.
    pub fn revision(&self) -> u64 {
        self.revision
    }

    /// Whether no name carries a message.
    pub fn is_empty(&self) -> bool {
        self.entries.is_empty()
    }

    /// The messages recorded for `name` — `record[name]`, `None` when absent.
    pub fn get(&self, name: &str) -> Option<&[SharedString]> {
        self.entries.get(name).map(Vec::as_slice)
    }

    /// Iterates `(name, messages)` in deterministic name order.
    pub fn iter(&self) -> impl Iterator<Item = (&SharedString, &[SharedString])> {
        self.entries
            .iter()
            .map(|(name, messages)| (name, &**messages))
    }

    /// The names carrying at least one message, in deterministic name order.
    pub fn names(&self) -> impl Iterator<Item = &SharedString> {
        self.entries.keys()
    }

    /// `record[name] = message` — the single-message spelling.
    ///
    /// Rebuilding a record is a new response: the revision is minted, so a
    /// form handed the result re-arms its fields.
    pub fn set(mut self, name: impl Into<SharedString>, message: impl Into<SharedString>) -> Self {
        self.entries.insert(name.into(), vec![message.into()]);
        self.revision = next_record_revision();
        self
    }

    /// `record[name] = [m0, m1, ...]` — the multiple-messages spelling, shown
    /// in the order given.
    pub fn set_many(
        mut self,
        name: impl Into<SharedString>,
        messages: impl IntoIterator<Item = impl Into<SharedString>>,
    ) -> Self {
        let messages: Vec<SharedString> = messages.into_iter().map(Into::into).collect();
        self.entries.insert(name.into(), messages);
        self.revision = next_record_revision();
        self
    }
}

impl Default for ValidationErrors {
    fn default() -> Self {
        Self::new()
    }
}

impl PartialEq for ValidationErrors {
    /// Content equality. Identity is [`Self::revision`] and deliberately
    /// excluded: two content-equal records can be two different responses.
    fn eq(&self, other: &Self) -> bool {
        self.entries == other.entries
    }
}

impl Eq for ValidationErrors {}

/// `validate` — returns `None` when the value is acceptable, or the message to
/// show when it is not.
///
/// v3 types this `(value) => ValidationError | true | null | undefined`, where
/// a returned error marks the field invalid; `None` here is that `null`.
pub type Validator<T> = Arc<dyn Fn(&T) -> Option<SharedString> + 'static>;
// `T` may be unsized (`str`); a type alias does not enforce bounds, so none
// is written here.

/// The messages a field should display, and whether it is invalid.
///
/// Order matches v3: an explicit `isInvalid` always wins, then server-supplied
/// `validationErrors`, then whatever `validate` returns.
#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub struct Validity {
    /// Whether the value is invalid.
    pub is_invalid: bool,
    /// The validation messages, if any.
    pub messages: Vec<SharedString>,
}

impl Validity {
    /// The first message, if any.
    ///
    /// The single-line text family — `Input`, `NumberField`, `InputOTP` —
    /// no longer renders this: their error slots show every message through
    /// [`Self::joined`], the way React Aria's `FieldError` default renders
    /// them. The compound controls (Switch, Checkbox, the date and time
    /// fields, the colour pickers) still show the one message this returns.
    pub fn first(&self) -> Option<SharedString> {
        self.messages.first().cloned()
    }

    /// Every message joined the way React Aria's `FieldError` default renders
    /// them: one string, messages space-joined in upstream order.
    pub fn joined(&self) -> String {
        self.messages
            .iter()
            .map(|message| &message[..])
            .collect::<Vec<&str>>()
            .join(" ")
    }
}

/// Resolves a field's validity from the three sources v3 defines.
///
/// * `is_invalid` — the controlled flag; forces invalid even with no message.
/// * `errors` — `validationErrors`, e.g. from a server round-trip.
/// * `validate_result` — whatever the `validate` function returned.
/// * `own_message` — the component's own `errorMessage` prop.
pub fn resolve(
    is_invalid: bool,
    errors: &[SharedString],
    validate_result: Option<SharedString>,
    own_message: Option<SharedString>,
) -> Validity {
    let mut messages: Vec<SharedString> = Vec::new();
    messages.extend(errors.iter().cloned());
    if let Some(m) = validate_result {
        messages.push(m);
    }
    // The component's own message is the fallback, not an addition: showing it
    // alongside a specific validation failure would duplicate the reason.
    if messages.is_empty() {
        if let Some(m) = own_message {
            messages.push(m);
        }
    }
    Validity {
        is_invalid: is_invalid || !messages.is_empty(),
        messages,
    }
}

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

    fn s(v: &str) -> SharedString {
        SharedString::from(v.to_owned())
    }

    #[test]
    fn clean_value_is_valid() {
        let v = resolve(false, &[], None, None);
        assert!(!v.is_invalid);
        assert!(v.messages.is_empty());
        assert_eq!(v.first(), None);
    }

    #[test]
    fn is_invalid_alone_marks_the_field() {
        // No message, but the caller says it is wrong.
        let v = resolve(true, &[], None, None);
        assert!(v.is_invalid);
        assert!(v.messages.is_empty());
    }

    #[test]
    fn a_validate_failure_marks_and_reports() {
        let v = resolve(false, &[], Some(s("Too short")), None);
        assert!(v.is_invalid);
        assert_eq!(v.first(), Some(s("Too short")));
    }

    #[test]
    fn server_errors_come_first() {
        let v = resolve(false, &[s("Already taken")], Some(s("Too short")), None);
        assert_eq!(v.messages, vec![s("Already taken"), s("Too short")]);
        assert_eq!(v.first(), Some(s("Already taken")));
    }

    #[test]
    fn own_message_is_a_fallback_not_an_addition() {
        // With a specific failure, the generic message would duplicate it.
        let v = resolve(
            false,
            &[],
            Some(s("Too short")),
            Some(s("Check this field")),
        );
        assert_eq!(v.messages, vec![s("Too short")]);
        // With nothing specific, it is what the field shows.
        let v = resolve(false, &[], None, Some(s("Check this field")));
        assert_eq!(v.messages, vec![s("Check this field")]);
        assert!(v.is_invalid);
    }

    #[test]
    fn joined_renders_every_message_in_upstream_order() {
        // React Aria's FieldError default is `validationErrors.join(' ')`:
        // all messages, one string, upstream order.
        let v = resolve(
            false,
            &[s("Already registered"), s("Check the server")],
            Some(s("Too short")),
            None,
        );
        assert_eq!(v.joined(), "Already registered Check the server Too short");
        assert_eq!(v.first(), Some(s("Already registered")));
        assert_eq!(resolve(false, &[], None, None).joined(), "");
    }

    #[test]
    fn a_record_maps_names_to_one_or_many_messages() {
        let record = ValidationErrors::new()
            .set("email", "Already registered")
            .set_many("roles", ["Role A", "Role B"]);
        assert_eq!(record.get("email"), Some(&[s("Already registered")][..]));
        assert_eq!(record.get("roles"), Some(&[s("Role A"), s("Role B")][..]));
        assert_eq!(record.get("absent"), None);
        assert!(!record.is_empty());
        // Deterministic name order, whatever the insertion order was.
        assert_eq!(
            record.names().cloned().collect::<Vec<_>>(),
            vec![s("email"), s("roles")]
        );
        assert_eq!(record.iter().count(), 2);
        assert!(ValidationErrors::new().is_empty());
    }

    #[test]
    fn a_clone_keeps_record_identity_while_a_new_record_mints() {
        let record = ValidationErrors::new().set("email", "Taken");
        let clone = record.clone();
        assert_eq!(clone.revision(), record.revision(), "clones share identity");
        assert_eq!(clone, record, "equality is content only");

        // The same content, rebuilt: a new response, not the old one.
        let rebuilt = ValidationErrors::new().set("email", "Taken");
        assert_eq!(rebuilt, record, "content equality holds");
        assert_ne!(
            rebuilt.revision(),
            record.revision(),
            "a genuinely new record must carry a new revision"
        );
        assert_ne!(
            ValidationErrors::default().revision(),
            ValidationErrors::default().revision(),
            "even two defaults are distinct responses"
        );

        // Rebuilding through a builder mints too: `default().set(..)` is a
        // fresh record, never a revision-0 orphan that would dedup against
        // another default-built record.
        let built = ValidationErrors::default().set("email", "Taken");
        assert_ne!(built.revision(), 0);
        assert_ne!(built.revision(), ValidationErrors::default().revision());
    }
}