backend/app/controllers/posts_controller.rb

@@ -128,7 +128,6 @@ class PostsController < ApplicationController
             provenance: { },
             tag_sources: { } }],
         fetch_metadata: true).first
-    return render_validation_error fields: preview[:validation_errors] if preview[:validation_errors].present?
 
     render json: {
         url: preview[:url],
@@ -141,6 +140,7 @@ class PostsController < ApplicationController
         video_ms: preview[:attributes]['video_ms'],
         field_warnings: preview[:field_warnings],
         base_warnings: preview[:base_warnings],
+        validation_errors: preview[:validation_errors],
         existing_post: compact_post(preview[:existing_post_id]) }
   rescue ArgumentError => e
     render_bad_request e.message

frontend/src/pages/posts/PostImportReviewPage.tsx

@@ -74,6 +74,7 @@ type PreviewResponse = {
   tags?:                 string
   fieldWarnings?:        Record<string, string[]>
   baseWarnings?:         string[]
+  validationErrors?:     Record<string, string[]>
   existingPost?:         {
     id:           number
     title:        string
@@ -249,7 +250,13 @@ const mergePreviewRow = (
 ): PostImportRow => {
   const fieldWarnings = preview.fieldWarnings ?? { }
   const baseWarnings = preview.baseWarnings ?? []
+  const validationErrors = preview.validationErrors ?? { }
   const metadataChanged = currentRow.metadataUrl !== preview.url
+  const hasWarnings =
+      Object.values (fieldWarnings).some (messages => messages.length > 0)
+      || baseWarnings.length > 0
+  const hasErrors =
+      Object.values (validationErrors).some (messages => messages.length > 0)
   const nextRow: PostImportRow = {
       ...currentRow,
       attributes: { ...currentRow.attributes },
@@ -260,6 +267,7 @@ const mergePreviewRow = (
       url: preview.url,
       fieldWarnings,
       baseWarnings,
+      validationErrors,
       existingPostId: preview.existingPost?.id,
       existingPost: preview.existingPost ?? undefined,
       skipReason:
@@ -274,10 +282,11 @@ const mergePreviewRow = (
           ? buildPreviewResetSnapshot (preview)
           : currentRow.resetSnapshot,
       status:
-          Object.keys (fieldWarnings).length > 0
-          || baseWarnings.length > 0
-          ? 'warning'
-          : 'ready' }
+          hasErrors
+          ? 'error'
+          : hasWarnings
+            ? 'warning'
+            : 'ready' }
 
   if (currentRow.provenance.title !== 'manual')
     nextRow.attributes.title = preview.title ?? ''

frontend/src/pages/posts/PostImportSourcePage.tsx

@@ -48,6 +48,7 @@ type PreviewResponse = {
   tags?:                 string
   fieldWarnings?:        Record<string, string[]>
   baseWarnings?:         string[]
+  validationErrors?:     Record<string, string[]>
   existingPost?:         {
     id:           number
     title:        string
@@ -75,6 +76,12 @@ const previewRowFromResult = (
 ): PostImportRow => {
   const fieldWarnings = result.fieldWarnings ?? { }
   const baseWarnings = result.baseWarnings ?? []
+  const validationErrors = result.validationErrors ?? { }
+  const hasWarnings =
+      Object.values (fieldWarnings).some (messages => messages.length > 0)
+      || baseWarnings.length > 0
+  const hasErrors =
+      Object.values (validationErrors).some (messages => messages.length > 0)
   const row: PostImportRow = {
       sourceRow,
       url: result.url,
@@ -89,7 +96,7 @@ const previewRowFromResult = (
 	  parentPostIds: '' },
       fieldWarnings,
       baseWarnings,
-      validationErrors: { },
+      validationErrors,
       provenance: {
 	  url: 'manual',
 	  title: 'automatic',
@@ -104,9 +111,11 @@ const previewRowFromResult = (
 	  automatic: result.tags ?? '',
 	  manual: '' },
       status:
-	  Object.keys (fieldWarnings).length > 0 || baseWarnings.length > 0
-	  ? 'warning'
-	  : 'ready',
+	  hasErrors
+	  ? 'error'
+	  : hasWarnings
+	    ? 'warning'
+	    : 'ready',
       skipReason: result.existingPost?.id != null ? 'existing' : undefined,
       existingPostId: result.existingPost?.id,
       existingPost: result.existingPost ?? undefined,
@@ -155,6 +164,36 @@ const fetchPreviewRows = async (
 			message:   string
 			url:       string }> = []
   let nextIndex = 0
+
+  const previewIssues = (
+      sourceRow: number,
+      url:       string,
+      requestError: unknown,
+  ): Array<{ sourceRow: number
+	     message:   string
+	     url:       string }> => {
+    if (!(isApiError<{
+	    message?:    string
+	    errors?:     Record<string, string[]>
+	    baseErrors?: string[]
+	}> (requestError)))
+      {
+	return [{
+	    sourceRow,
+	    message: '入力を確認してください．',
+	    url }]
+      }
+
+    const fieldMessages = Object.values (requestError.response?.data?.errors ?? { }).flat ()
+    const baseMessages = requestError.response?.data?.baseErrors ?? []
+    const messages = [...new Set ([...fieldMessages, ...baseMessages])]
+    return (messages.length > 0 ? messages : [requestError.response?.data?.message ?? '入力を確認してください．'])
+        .map (message => ({
+	    sourceRow,
+	    message,
+	    url }))
+  }
+
   const worker = async () => {
     while (nextIndex < rows.length)
     {
@@ -172,21 +211,7 @@ const fetchPreviewRows = async (
       {
         if (signal.aborted)
           return
-
-        const apiMessage =
-            isApiError<{
-                message?:    string
-                errors?:     Record<string, string[]>
-                baseErrors?: string[]
-            }> (requestError)
-            ? (requestError.response?.data?.errors?.url?.[0]
-               ?? requestError.response?.data?.message
-               ?? requestError.response?.data?.baseErrors?.[0])
-            : undefined
-        issues.push ({
-	    sourceRow: row.sourceRow,
-	    message: apiMessage ?? '入力を確認してください．',
-	    url: row.url })
+        issues.push (...previewIssues (row.sourceRow, row.url, requestError))
       }
     }
   }