[gatsby-plugin-sharp] Requires incorrect gatsby module in mono-repo

[martin-css]

Description

We run Gatsby inside a Docker container to build our web site. Recently we had added a fair number of images and noticed a strange issue where our automed e2e test was failing due to images not being found (404 error). Investigation of the build confirmed that the relevant folders has been generated in public/static but were empty.

This was strange because it worked when being built locally on a developer and all images were produced. However, when running on our CI server, this was failing to produce all the images.

Given that the build was happening in a Docker container we assumed this must be some sort of race condition that occurs depending on the physical hardware used. Investigation confirmed that the CI server was taking longer to process each images and hence the overall build was completed before all images had been created.

This was strange as I was aware that the bootstrap process was meant to wait until all outstanding jobs were completed.

After some debugging, I found the root of the problem. gatsby-plugin-sharp acquires the bound action creators via this line:

const { boundActionCreators } = require(`gatsby/dist/redux/actions`)

We run Gatsby iniside a monorepo. The plugin is correctly sending the CREATE_JOB and END_JOB actions but these were going to a totally different Redux store due to the way Yarn had hoisted the dependencies! The require will find the "closest" gatsby which might not be the gatsby module executing.

Hence the correct store was never receiving the actions and the code in the bootstrap process to check for active jobs would pass even though the plugin was still working.

Corrective Action

gatsby-plugin-sharp should use the actions that are passed to the gatsby-node API file. This will ensure the plugin is always referring to the correct store.

I will submit a pull request with this change. I've mainly created this issue for reference purposes in case it helps anyone else.

Other considerations

I've not had time to check but any other plugins that pull out the boundActionCreators from require('gatsby/dist/redux/actions') would also suffer from this bug of referencing the wrong Redux store which could lead to all sorts of weird behaviour.