Ask questionsImage loading (via graphql) from front matter fails on Hot Reload when editing MDX while theme development via yarn workspaces


Hot reload of the post written in MDX (i.e. when a post is edited) fails when we pull featured image data inside graphql query with following error

  errors: [
    TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received type undefined
        at validateString (internal/validators.js:112:11)
        at Object.resolve (path.js:981:7)
        at findLinkedFileNode (/Users/bornshrewd/code/blog/theme-test/node_modules/gatsby/dist/schema/resolvers.js:207:47)
        at resolveValue (/Users/bornshrewd/code/blog/theme-test/node_modules/gatsby/dist/schema/resolvers.js:222:108)
        at /Users/bornshrewd/code/blog/theme-test/node_modules/gatsby/dist/schema/resolvers.js:219:10
        at processTicksAndRejections (internal/process/task_queues.js:85:5)
        at async Promise.all (index 2)
        at async Promise.all (index 2)
        at async Promise.all (index 0)
        at async Promise.all (index 0)
        at async Promise.all (index 0) {
      message: 'The "path" argument must be of type string. Received type undefined',
      locations: [Array],
      path: [Array]
  data: [Object: null prototype] {
    allMdx: [Object: null prototype] { edges: [Array] }


"gatsby-theme-blog-starter" threw an error while running the createPages lifecycle:

The "path" argument must be of type string. Received type undefined

GraphQL request:13:13
12 |             slug
13 |             image {
   |             ^
14 |               publicURL

Steps to reproduce

I'm using MDX inside gatsby themes and my post front matter looks like

title: Title
description: Description
pagetitle: Page Title
summary: Page Description
date: '2017-01-28'
update_date: '2017-01-29'
  - technology
  - tech
slug: theme
published: true
image: ./atech-guide.png

Page Text

Pages for posts are dynamically created using the following query

      filter: {frontmatter: {published: {eq: true}}}
    ) {
      edges {
        node {
          frontmatter {
            image {

Code link:

Code to generate the pages dynamically lies inside the theme.

As you can see I pass the static URL of my image to use it inside SEO component.

While developing the theme by setting up yarn workspace, I noticed that when I edit my MDX content Hot reloading fails with error as mentioned above.

But when I publish my theme and use it in my website via npm version Hot reloading is successful with no errors.

Also, it's just the issue with image data because when I remove the image data from graphql query hot reloading is successful

I'm not sure what's wrong. Please let me know in case I'm missing something

My theme URL:

Blog where I use my theme:

Yarn Command: yarn workspace atech-guide clean && yarn workspace atech-guide develop

In case it's needed, I will put my yarn workspace on git for debugging this issue

Expected result

Hot reloading of post while editing should not fail

Actual result

Hot reloading of the post while editing fails with the error above.


    OS: macOS 10.14.5
    CPU: (8) x64 Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
    Shell: 3.2.57 - /bin/bash
    Node: 12.8.1 - /usr/local/bin/node
    Yarn: 1.17.3 - /usr/local/bin/yarn
    npm: 6.11.3 - /usr/local/bin/npm
    Python: 2.7.10 - /usr/bin/python
    Chrome: 76.0.3809.132
    Firefox: 68.0.1
    Safari: 12.1.1
    gatsby-cli: 2.7.8

CC: @ChristopherBiscardi


Answer questions Jc2k

This seems to be a dupe, and the fix attached to it works for me.


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