Festival/edition slug editing: dashes unusable while typing, no uniqueness check, generic conflict error

[chiptus]

Problem

Found while testing FestivalDialog's edit flow (pre-existing, not introduced by #495). All three affect both FestivalDialog.tsx and FestivalEditionManagement.tsx, since they share the same slug helpers and mutation-error pattern.

1. Can't type a dash into the slug field

handleSlugChange runs sanitizeSlug/generateSlug (src/lib/slug.ts) on every keystroke via the controlled input's onChange:

function handleSlugChange(slug: string) {
  const cleanSlug = sanitizeSlug(slug);
  setFormData((prev) => ({ ...prev, slug: cleanSlug }));
  ...
}

generateSlug strips leading/trailing hyphens:

.replace(/^-+|-+$/g, "")

Typing "boom-festival" character by character passes through the state "boom-" after the 5th keystroke — at that instant the hyphen is trailing, so it gets stripped immediately, snapping the field back to "boom". The next keystroke ("f") then appends directly to "boom", not "boom-", so a hyphen typed in the middle of a slug can never survive a normal sequence of keystrokes. (The only way to get a hyphenated slug into the field today is to paste the whole value at once, which sidesteps the per-keystroke sanitization.)

2. No client-side uniqueness check

handleSubmit in both dialogs validates only presence and format (isValidSlug) before submitting:

if (!isValidSlug(formData.slug)) {
  toast({ title: "Error", description: "Please enter a valid slug", ... });
  return;
}

There's no query against existing festivals/editions to warn about a taken slug before hitting submit — the only enforcement is the DB's unique constraint (festivals_slug_unique, festival_editions_slug_festival_unique), discovered only after a failed save.

3. Generic error message on a real unique-constraint conflict

useUpdateFestivalMutation's (and the edition equivalent's) onError doesn't discriminate the failure cause:

onError: (error) => {
  console.error("Error updating festival:", error);
  toast({ title: "Error", description: "Failed to update festival", variant: "destructive" });
},

A slug conflict (Postgres 23505 unique_violation) surfaces the same generic "Failed to update festival" as any other failure, giving the user no indication of what to actually fix.

Related

#467 already designs the right treatment for this exact class of problem — explicit slug field, format validation, a client-side uniqueness pre-check, and mapping a constraint-violation error to a friendly message — but scoped to the sets/artists edit forms only. This issue is the same treatment needed for the festival/festival-edition edit forms, which #467 doesn't cover.

The dash-typing bug (#1) is a new finding not mentioned in #467's design — worth accounting for there too, since #467 also plans to reuse isValidSlug/sanitizeSlug from src/lib/slug.ts for its new slug field, which would inherit the same per-keystroke corruption unless the field sets its value on blur/paste rather than sanitizing every keystroke.

Suggested fix

• Sanitize on blur (or debounce/only strip trailing hyphens on submit), not on every keystroke — so a hyphen typed mid-string survives.
• Add a lightweight uniqueness query (scoped appropriately — global for festivals, per-festival for editions) run before submit, surfaced as a form/toast warning.
• In both useUpdateFestivalMutation's and the edition mutation's onError, inspect the Postgrest error code (23505) and show a specific "This slug is already taken" message instead of the generic fallback.

Context

Reported during review of PR #495 (fix-157/finish-mutate-migration), which touches the same files for an unrelated mutateAsync→mutate migration but didn't introduce these bugs.