feat(19.6.1-05): persist picked relation labels across FormView tab remount

- FORM_REMEMBER_LABEL inject so hosts keep picked option names
- RelationField choose() writes the label before emit
- Vitest backstops remount and tab-switch labeling

Co-authored-by: Cursor <cursoragent@cursor.com>

admin/src/components/form/fields/RelationField.vue

@@ -1,10 +1,11 @@
 <script setup lang="ts">
-import { computed, onBeforeUnmount, ref, watch } from 'vue'
+import { computed, inject, onBeforeUnmount, ref, watch } from 'vue'
 import { ChevronDown, Lock, X } from '@lucide/vue'
 import { api } from '../../../api/client'
 import type { RelationOption } from '../../../api/types'
 import { t } from '../../../app/i18n'
 import type { FieldControlProps } from '../control'
+import { FORM_REMEMBER_LABEL } from '../formContext'
 
 // Relation field (D-17, D-18, D-26), three modes from the schema:
 //   readOnly  the label from meta.labels only, no control
@@ -22,6 +23,7 @@ import type { FieldControlProps } from '../control'
 // refuses the change in any case.
 const props = defineProps<FieldControlProps>()
 const emit = defineEmits<{ 'update:modelValue': [value: number | number[] | null] }>()
+const rememberLabel = inject(FORM_REMEMBER_LABEL, undefined)
 
 const PER_PAGE = 20
 const SEARCH_DEBOUNCE = 300
@@ -226,6 +228,13 @@ function choose(entry: Entry): void {
   if (entry.locked) {
     return
   }
+  if (entry.value !== null) {
+    rememberLabel?.(props.field.name, {
+      value: entry.value,
+      label: entry.label,
+      locked: entry.locked || undefined,
+    })
+  }
   if (mode.value === 'multiple') {
     if (entry.value !== null && !selectedIds.value.includes(entry.value)) {
       emit('update:modelValue', [...selectedIds.value, entry.value])

admin/src/components/form/formContext.ts

@@ -5,7 +5,7 @@
 // provider (settings pages) gets the defaults of the injecting control.
 import { ref, type InjectionKey, type Ref } from 'vue'
 import type { FileRoutes } from '../../api/files'
-import type { AdminDependentOptionsResult, AdminRecord, FormField, PermissionRecordLock } from '../../api/types'
+import type { AdminDependentOptionsResult, AdminRecord, FormField, PermissionRecordLock, RelationOption } from '../../api/types'
 
 /** Read-only view of the form's current values. */
 export const FORM_VALUES: InjectionKey<Readonly<Ref<AdminRecord>>> = Symbol('summer.form.values')
@@ -171,5 +171,13 @@ export interface FieldScope {
 
 export const FIELD_SCOPE: InjectionKey<FieldScope> = Symbol('summer.form.fieldScope')
 
+/**
+ * Form hosts persist a picked relation option so a remounted RelationField
+ * can seed its id→label cache from props.labels; a host without a provider
+ * is a no-op.
+ */
+export const FORM_REMEMBER_LABEL: InjectionKey<(field: string, option: RelationOption) => void> =
+  Symbol('summer.form.rememberLabel')
+
 /** Dependent options per field path and sibling value, for the life of a form view. */
 export const DEPENDENT_CACHE: InjectionKey<Map<string, AdminDependentOptionsResult>> = Symbol('summer.form.dependentCache')

admin/src/components/relation/RelationChildModal.vue

@@ -11,7 +11,7 @@ import {
 import { Trash2, X } from '@lucide/vue'
 import { api } from '../../api/client'
 import { childFileRoutes } from '../../api/files'
-import type { AdminRecord, ControllerParams, FormField, RecordMeta, RelationSchema } from '../../api/types'
+import type { AdminRecord, ControllerParams, FormField, RecordMeta, RelationOption, RelationSchema } from '../../api/types'
 import { message, t } from '../../app/i18n'
 import { CHILD_SESSION_HEADER, SESSION_HEADER, newSessionKey } from '../../app/sessionKey'
 import FormErrorBanner from '../form/FormErrorBanner.vue'
@@ -20,6 +20,7 @@ import FormTabs from '../form/FormTabs.vue'
 import {
   FORM_ENABLED_LOCALES,
   FORM_PATCH,
+  FORM_REMEMBER_LABEL,
   FORM_SESSION,
   FORM_TRIGGER_NOTES,
   FORM_VALUES,
@@ -214,6 +215,19 @@ provide(FORM_ENABLED_LOCALES, enabledLocales)
 // a child field of the same name.
 provide(FORM_TRIGGER_NOTES, readonly(ref<Record<string, string>>({})))
 
+function rememberRelationLabel(field: string, option: RelationOption): void {
+  const current = labels.value[field] ?? []
+  const index = current.findIndex((item) => item.value === option.value)
+  const next = [...current]
+  if (index >= 0) {
+    next[index] = option
+  } else {
+    next.push(option)
+  }
+  labels.value = { ...labels.value, [field]: next }
+}
+provide(FORM_REMEMBER_LABEL, rememberRelationLabel)
+
 function update(name: string, value: unknown): void {
   values.value = { ...values.value, [name]: value }
   if (errors.value[name]) {

admin/src/views/FormView.vue

@@ -4,7 +4,7 @@ import { onBeforeRouteLeave, onBeforeRouteUpdate, useRoute, useRouter } from 'vu
 import { ArrowLeft, Trash2 } from '@lucide/vue'
 import { api } from '../api/client'
 import { parentFileRoutes } from '../api/files'
-import type { AdminRecord, ErrorEnvelope, FormView, RecordEnvelope, RecordMeta } from '../api/types'
+import type { AdminRecord, ErrorEnvelope, FormView, RecordEnvelope, RecordMeta, RelationOption } from '../api/types'
 import { controllerIdFromParams, controllerPath } from '../app/controllerRoutes'
 import { currentLocale, message, t } from '../app/i18n'
 import { loadControllerAssets } from '../app/pluginAssets'
@@ -21,6 +21,7 @@ import {
   FORM_LOCALE,
   FORM_PATCH,
   FORM_PERMISSION_LOCKS,
+  FORM_REMEMBER_LABEL,
   FORM_SESSION,
   FORM_TRIGGER_NOTES,
   FORM_VALUES,
@@ -247,6 +248,18 @@ function adopt(record: RecordEnvelope | undefined): void {
   saved.value = snapshot(editablePayload(fields.value, values.value, mode, permissionLocks.value))
 }
 
+function rememberRelationLabel(field: string, option: RelationOption): void {
+  const current = labels.value[field] ?? []
+  const index = current.findIndex((item) => item.value === option.value)
+  const next = [...current]
+  if (index >= 0) {
+    next[index] = option
+  } else {
+    next.push(option)
+  }
+  labels.value = { ...labels.value, [field]: next }
+}
+
 async function load(): Promise<void> {
   loading.value = true
   failed.value = false
@@ -336,6 +349,7 @@ function update(name: string, value: unknown): void {
 // that field's errors like an edit (D-07, D-08).
 provide(FORM_VALUES, computed(() => values.value))
 provide(FORM_PATCH, update)
+provide(FORM_REMEMBER_LABEL, rememberRelationLabel)
 provide(FORM_LOCALE, computed(() => schema.value?.meta.locale || currentLocale.value))
 provide(FORM_ENABLED_LOCALES, computed(() => schemaEnabledLocales(schema.value?.meta)))
 provide(FORM_ASSETS, () => assetsReady)