fix text defaultValue not accepting null

Author: dcousens

packages/core/src/fields/types/text/index.ts

@@ -27,7 +27,7 @@ export type TextFieldConfig<ListTypeInfo extends BaseListTypeInfo> =
       match?: { regex: RegExp, explanation?: string }
       length?: { min?: number, max?: number }
     }
-    defaultValue?: string
+    defaultValue?: string | null
     db?: {
       isNullable?: boolean
       map?: string
@@ -94,18 +94,20 @@ export function text <ListTypeInfo extends BaseListTypeInfo>(
 
     // defaulted to false as a zero length string is preferred to null
     const isNullable = config.db?.isNullable ?? false
-    const fieldLabel = config.label ?? humanize(meta.fieldKey)
+    if (defaultValue_ === null && !isNullable) throw new Error(`The text field at ${meta.listKey}.${meta.fieldKey} cannot default to null`)
 
     assertReadIsNonNullAllowed(meta, config, isNullable)
+
+    const defaultValue = isNullable ? (defaultValue_ ?? null) : (defaultValue_ ?? '')
+    const fieldLabel = config.label ?? humanize(meta.fieldKey)
     const mode = isNullable ? 'optional' : 'required'
-    const defaultValue = isNullable === false || defaultValue_ !== undefined ? defaultValue_ || '' : undefined
-    const hasValidation = resolveHasValidation(config)
+    const hasValidation = resolveHasValidation(config) || !isNullable // we make an exception for Text
 
     return fieldType({
       kind: 'scalar',
       mode,
       scalar: 'String',
-      default: defaultValue === undefined ? undefined : { kind: 'literal', value: defaultValue },
+      default: defaultValue === null ? undefined : { kind: 'literal', value: defaultValue },
       index: isIndexed === true ? 'index' : isIndexed || undefined,
       map: config.db?.map,
       nativeType: config.db?.nativeType,