gatsbyjs/gatsby · error · Error

Encountered unknown module type: ${module.type}. Please open

Error message

Encountered unknown module type: ${module.type}. Please open an issue.

What it means

Thrown from the webpack splitChunks `lib.name` callback when a module that passes the lib-chunk test (>160kb, from node_modules, not CSS) has no `libIdent` method. `libIdent` produces a stable, context-relative identifier used to hash the chunk name; some webpack 5 module types (e.g. raw/asset/external modules) do not implement it. Gatsby treats this as an internal invariant and asks the user to file an issue.

Source

Thrown at packages/gatsby/src/utils/webpack.config.js:694

            return FRAMEWORK_BUNDLES_REGEX.test(module.nameForCondition())
          },
          priority: 40,
          // Don't let webpack eliminate this chunk (prevents this chunk from becoming a part of the commons chunk)
          enforce: true,
        },
        // if a module is bigger than 160kb from node_modules we make a separate chunk for it
        lib: {
          test(module) {
            return (
              !isCssModule(module) &&
              module.size() > 160000 &&
              /node_modules[/\\]/.test(module.identifier())
            )
          },
          name(module) {
            const hash = crypto.createHash(`sha1`)
            if (!module.libIdent) {
              throw new Error(
                `Encountered unknown module type: ${module.type}. Please open an issue.`
              )
            }

            hash.update(module.libIdent({ context: program.directory }))

            return hash.digest(`hex`).substring(0, 8)
          },
          priority: 30,
          minChunks: 1,
          reuseExistingChunk: true,
        },
        commons: {
          name: `commons`,
          // if a chunk is used on all components we put it in commons (we need at least 2 components)
          minChunks: Math.max(componentsCount, 2),
          priority: 20,
        },

View on GitHub (pinned to 8b06340921)

Solutions

1. Identify the large dependency (>160kb) recently added and check whether it ships asset/WASM modules.
2. Update Gatsby, webpack, and relevant loaders to their latest compatible versions.
3. If reproducible, file the issue requested in the message with the dependency list and module.type.
4. As a temporary workaround, configure `splitChunks` overrides via `gatsby-node.js` `onCreateWebpackConfig` to exclude the offending module from the lib chunk.

Example fix

// gatsby-node.js workaround: exclude asset modules from lib chunk
exports.onCreateWebpackConfig = ({ stage, actions, getConfig }) => {
  const config = getConfig()
  if (config.optimization && config.optimization.splitChunks) {
    const lib = config.optimization.splitChunks.cacheSets?.lib || config.optimization.splitChunks.cacheGroups?.lib
    if (lib && lib.test) {
      const orig = lib.test
      lib.test = (module) => orig(module) && module.libIdent !== undefined
    }
  }
  actions.replaceWebpackConfig(config)
}

// Defensive name callback that skips modules without libIdent
name(module) {
  if (!module.libIdent) return 'fallback-chunk'
  const hash = crypto.createHash('sha1')
  hash.update(module.libIdent({ context: program.directory }))
  return hash.digest('hex').substring(0, 8)
}

When it happens

Trigger: A dependency in `node_modules` larger than 160kb ships a module type for which webpack does not provide `libIdent` (e.g. an asset/data/native module surfaced through a loader chain). The `name` callback is invoked during chunk optimization and the guard trips.

Common situations: Adding a heavy dependency (WASM, large data files, native bindings) whose webpack module type lacks `libIdent`; upgrading webpack-related Gatsby internals or a loader that changes the emitted module type; very rarely hit, typically indicates a loader/bundler edge case.

Related errors

• something changed in webpack but I don't know what
• The result of this StaticQuery could not be fetched. This i
• ${err}
• Missing compiler
• Missing required params

AI-assisted analysis of gatsbyjs/gatsby@8b06340921 (2026-08-13). Data as JSON: /api/errors/82676ef4660b18cb. Report an issue: GitHub.