Pattern — Form page

Status: v0.1.0 — Draft. Promoted from the Shopify Polaris parity scan (meta/docs/stack #091). Source: https://polaris.shopify.com/patterns (Page + ContextualSaveBar).

R1 — When to use (vs wizard / inline edit / one-thing)

• Form page (this): the user edits many related fields of one record on one page, saving as a unit (settings, profile, product edit).
• Wizard (specs/patterns/wizard-multistep.kmd): a sequential first-time flow with per-step gates.
• Inline edit (specs/patterns/inline-edit.kmd): change one value in place without a save bar.
• One-thing-per-page governs the granularity within a step, not this all-at-once editing surface.

R2 — Section grouping

Fields are grouped into titled sections (each an <h2> + optional description) that chunk a long form into scannable units. Sections are visual grouping, not separate submits — the page saves as a whole (R3).

R3 — Sticky save bar (dirty-driven)

• The form starts clean; a save/discard bar appears only when the form becomes dirty (a value changed), and pins to the top or bottom so it is always reachable while scrolling.
• It holds a primary Save and a secondary Discard; Save is disabled while invalid (R5) and shows a pending state while saving.
• Discard reverts all fields to the last-saved state (with a confirm if changes are substantial).

R4 — Unsaved-changes guard

Navigating away (back, link, close, route change) while dirty prompts a confirm ("You have unsaved changes") — never lose edits silently. Pairs with specs/navigation/back-behavior.kmd. A successful Save clears the dirty state and the guard.

R5 — Validation

• Validate on Save (and optionally on blur per field). On failure, show a validation summary that links to the first offending field (the GOV.UK/koder_web_kit error-summary), plus inline messages per specs/errors/user-facing-messages.kmd.
• Focus moves to the summary / first error on a failed save.

R6 — Accessibility & i18n

• Sections use real headings; each field has an associated label; the save bar is keyboard-reachable and its state (disabled/pending) is announced.
• The dirty→save-bar appearance is announced politely (not a focus steal).
• All chrome (Save/Discard, section titles, the unsaved-changes prompt) is translatable per specs/i18n/contract.kmd.

Não-escopo

• Step-by-step flows (specs/patterns/wizard-multistep.kmd).
• Single-value editing (specs/patterns/inline-edit.kmd).
• Individual field components (text field, money input, selects).
• Autosave-without-a-save-bar surfaces (a different model).