Preliminary Checks

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Description

While writing markdown I use thumbnail and parent in the frontmatter to render a thumbnail in lists and to describe my site taxonomy. This blog was created in 2019, and I recently tried to upgrade all dependencies from Gatsby 3 to 5.

This issue occurs in my custom "createPages" code, though it persists when running the site and testing in the iGraphQL explorer

Diagnosis

While reading node-model.js I console.log'd ids and noted it was a Set

  findRootNodeAncestor(obj, predicate = null) {
    let iterations = 0;
    let ids = this._rootNodeMap.get(obj);
    console.log(ids); // DEBUG
    if (!ids) {
      ids = [];
    }
    if (obj !== null && obj !== void 0 && obj.parent) {
      ids.push(obj.parent);
    }

Set(1) { '1afed4c9-65b6-512d-97ab-5c2f6a7aca3b' }

Invesigating _rootNodeMap indeed, it is created as a set

    // don't need to track node itself
    if (!isNode) {
      let nodeIds = rootNodeMap.get(data);
      if (!nodeIds) {
        nodeIds = new Set([nodeId]);
      } else {
        nodeIds.add(nodeId);
      }
      rootNodeMap.set(data, nodeIds);
    }

There appears to be a type disparity between ids as a Set (.add) and ids as an Array (.push)

This code was added in Oct 2022 and includes the type disparity
696a7ba

Fix

Update the findRootNodeAncestor function to consistently treat nodeIds as a Set

#39262

Reproduction Link

https://github.com/sdobz/gatsby-markdown-frontmatter-repro

Steps to Reproduce

1. npm init gatsby
   a. Enable markdown plugin
2. https://www.gatsbyjs.com/docs/how-to/images-and-media/working-with-images-in-markdown/
3. Create a markdown page with "parent" in the frontmatter and "thumbnail" pointing to a file

Expected Result

I expect to see one page listed in the print

Actual Result

I see graphql errors

{
  errors: [
    TypeError: ids.push is not a function
        at LocalNodeModel.findRootNodeAncestor
(/home/vkhougaz/projects/gatsby-markdown-frontmatter-issue/node_modules/gatsby/src/schema/node-model.js:527:11)
        at ContextualNodeModel.findRootNodeAncestor
(/home/vkhougaz/projects/gatsby-markdown-frontmatter-issue/node_modules/gatsby/src/schema/node-model.js:684:27)
        at fileByPathResolver
(/home/vkhougaz/projects/gatsby-markdown-frontmatter-issue/node_modules/gatsby/src/schema/resolvers.ts:526:46)
        at processTicksAndRejections (node:internal/process/task_queues:105:5)
        at async Promise.all (index 0)
        at async Promise.all (index 0)
        at async Promise.all (index 0)
        at async Promise.all (index 1)
        at async Promise.all (index 0) {
      path: [Array],
      locations: [Array],
      extensions: [Object: null prototype] {}
    }
  ],
  data: [Object: null prototype] {
    allMarkdownRemark: [Object: null prototype] { edges: [Array] }
  }
}

Environment

System:
    OS: Linux 5.15 Ubuntu 20.04.6 LTS (Focal Fossa)
    CPU: (16) x64 AMD Ryzen 7 3800XT 8-Core Processor
    Shell: 5.8 - /usr/bin/zsh
  Binaries:
    Node: 22.14.0 - /nix/store/bmakyv5ip1wc9jk155glzdw4vnnrym04-nodejs-22.14.0/bin/node
    Yarn: 1.22.22 - /nix/store/sfh8adsjz44xyismwlzamq25k6lk9igl-yarn-1.22.22/bin/yarn
    npm: 10.9.2 - /nix/store/bmakyv5ip1wc9jk155glzdw4vnnrym04-nodejs-22.14.0/bin/npm
  npmPackages:
    gatsby: ^5.14.1 => 5.14.1 
    gatsby-cli: ^5.14.0 => 5.14.0 
    gatsby-plugin-sharp: ^5.14.0 => 5.14.0 
    gatsby-source-filesystem: ^5.14.0 => 5.14.0 
    gatsby-transformer-remark: ^6.14.0 => 6.14.0 
    gatsby-transformer-sharp: ^5.14.0 => 5.14.0

Config Flags

No response