gatsbyjs/gatsby · error

[deprecated]: ${deprecationReason}

Error message

[deprecated]: ${deprecationReason}

What it means

Generic deprecation guard in webpack-plugins: the webpack built-in/optimize plugin factory was created with a deprecationReason, so any use of that plugin prints the console.warn. The input at fault is the deprecated webpack plugin name used in the webpack config or internal plugin list.

Source

Thrown at packages/gatsby/src/utils/webpack-plugins.ts:12

import webpack, { WebpackPluginInstance } from "webpack"

const plugin =
  (
    name: string,
    optimize?: boolean,
    deprecationReason?: string
  ): ((...args: any) => WebpackPluginInstance) =>
  (...args: any): WebpackPluginInstance => {
    if (deprecationReason) {
      // TODO add proper deprecation function to reporter
      console.warn(`[deprecated]: ${deprecationReason}`)
    }

    const WebpackPlugin = (optimize ? webpack.optimize : webpack)[name]
    return new WebpackPlugin(...args)
  }

export const builtinPlugins = {
  normalModuleReplacement: plugin(`NormalModuleReplacementPlugin`),
  contextReplacement: plugin(`ContextReplacementPlugin`),
  ignore: plugin(`IgnorePlugin`),
  watchIgnore: plugin(`WatchIgnorePlugin`),
  banner: plugin(`BannerPlugin`),
  prefetch: plugin(`PrefetchPlugin`),
  automaticPrefetch: plugin(`AutomaticPrefetchPlugin`),
  define: plugin(`DefinePlugin`),
  provide: plugin(`ProvidePlugin`),
  hotModuleReplacement: plugin(`HotModuleReplacementPlugin`),
  sourceMapDevTool: plugin(`SourceMapDevToolPlugin`),

View on GitHub (pinned to e85d62f177)

Solutions

1. Replace the deprecated webpack plugin with its modern webpack 5 equivalent
2. Remove usage of the plugin if it is no longer needed
3. Update Gatsby/plugin code that still wires up deprecated optimize plugins

When it happens

Trigger: Thrown at packages/gatsby/src/utils/webpack-plugins.ts:12 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of gatsbyjs/gatsby@e85d62f177 (2026-08-26). Data as JSON: /api/errors/bc5c2cad1e929be8. Report an issue: GitHub.