環境

MacOS Catalina 10.15.7
nodejs v16.8.0
Gatsby CLI version: 4.18.0

"gatsby": "^4.18.0",
"react": "^18.1.0",
"react-dom": "^18.1.0"
"gatsby-plugin-image": "^2.18.0",
"gatsby-plugin-sass": "^5.18.0",
"gatsby-plugin-sharp": "^4.18.0",
"gatsby-source-wordpress": "^6.18.0",
"gatsby-transformer-sharp": "^4.18.0",
"prettier": "^2.7.1",
"sass": "^1.53.0"

Local 6.4.1
WordPress 5.9.3

WP Gatsby 2.3.3
WP GraphQL 1.8.6
WP Multibyte Patch 2.9

症状

Local で WordPress を起動
.env の WPGRAPHQL_URL に Local の graphql を設定

gatsby-config.js

require('dotenv').config();

module.exports = {
  plugins: [
    {
      resolve: `gatsby-source-wordpress`,
      options: {
        url: process.env.WPGRAPHQL_URL,
      },
    },
    `gatsby-plugin-image`,
    `gatsby-plugin-sharp`,
    `gatsby-transformer-sharp`,
    `gatsby-plugin-sass`,
  ],
}

gatsby develop で下記エラー

Missing onError handler for invocation 'building-schema', error was 'Names must match /^[_a-zA-Z][_a-zA-Z0-9]*$/ but "WpTemplate_空白" does not.'. Stacktrace was 'GraphQLError: Names must match /^[_a-zA-Z][_a-zA-Z0-9]*$/ but "WpTemplate_空白" does not.

対応

WordPress管理画面で 設定 一般 サイトの言語 を 日本語 から English(United States) に変更