[bug]: ☂️ umbrella issue for cache and over-eager persistence issues

[DSchau]

Description

In this umbrella issue, I'd like to provide a means for others to share any issues encountered regarding caching, specifically in instances when the solution to a problem you were facing was remediated by removing the cache (e.g. rm -rf .cache).

Issues that we have seen before (but generally have not been able to reproduce) can usually be classified as one of the following:

1. Remote content sourced by a plugin is available (e.g. in the database, CMS, etc.) but is not available after a local re-build
2. A local plugin source code changed, but the change(s) do not seem to have taken effect
3. Local content (e.g. images, Markdown, etc.) were changed, but the changes do not seem to show up after a build

If any of these scenarios, or more broadly speaking, if you've ran into a problem where content wasn't appearing appropriately and deleting the cache solved this problem--then please chime in!

Intent

If we can reliably reproduce these types of issues and scenarios, we can harden our cache and improve the experience for all Gatsby users. Specifically, if we can reliably reproduce we can fix the underlying issue and then author end-to-end tests to ensure that the caching issue remains fixed.

Template

Please use the following template to report an issue so that we can most effectively debug the underlying issue.

Note: it is extremely important that you provide as much information as possible for the reproduction step. The more info and clearer the reproduction, the better we will be able to debug and ship fixes to these issues!

## Description

<!-- What led you to delete the cache? What was the exact problem that deleting the cache seemed to have fixed? -->

## Reproduction

<!-- Please, please provide detailed steps to reproduce. Ideally a Github repository where we can reproduce the issue(s) ourselves, as well. -->

## Environment Info

<!-- Run `npx gatsby info --clipboard` in the root of your Gatsby app and paste the output here -->

[mrispoli24]

I think I ran into this issue and after much frustration I started this issue but ended up closing it after deleting the public folder and getting everything to work. I do believe this sounds a lot like what others are experiencing though.

[nickytonline]

I built my site off of the Netlify CMS starter, https://github.com/nickytonline/www.iamdeveloper.com. ‪It has deleting the .cache as part of their build steps. See https://github.com/netlify-templates/gatsby-starter-netlify-cms/blob/master/package.json#L40‬

Not sure why, but they must have a good reason to delete the .cache.

I remember when I started off with another starter site, I had to delete the .cache frequently, but this was pre-Gatsby 2.

[keithmifsud]

Please bear in mind that I am not 100% sure this was the cause of the issue forcing me to delete the .cache directory but it did fix the issue as soon as I did. I have a json file with an array of objects. I decided to give each object an identifier key. Gatsby does not like this key name, maybe it conflicts with an internal key name. I renamed the identifier to name but the related changes were not being built until I deleted the .cache directory.

[endymion1818]

In working with several developers using GatsbyJS over the past 9 months I’ve only had this isssue come up once. A colleague was experiencing graphql errors because an API wasn’t being reached. We had recently changed how we fetch data (using gatsby-source-Wordpress) in Gatsby-config.js. When he updated his master branch, running the cli command “gatsby develop” still used the old settings. Deleting .cache solved the issue.

[oobidin]

I've been working with GatsbyJS last 6 months and I faced some issues when you update some local content (MDs and JSONs in our case) and it doesn't update. Actually, we've created the yarn clean command with the content: rm -rf public && rm -rf .cache to solve such kind of issues.

[trotzig]

We updated our content types in contentful (removed some types, added some). Removing the cache folder made the dev server start up again. Cc @axhamre.

[kylefraser]

We've run into an issue with contentful where, when we've added images via a rich-text, we've had to delete the .cache folder in order to query additional properties with GraphQL on the embedded asset.

For instance, we've added images, re-started the dev server, and were still unable to query image properties like

target {
   fields {
      file {
         url
      }
   }
}

deleting the .cache folder, solved this for us.

[vacas5]

I abstracted a lot of functions utilized inside my sourceNodes function into a separate file. Changes made in that file were not detected by cache busting, and so any time I changed the code in my abstracted file, I would have to clear the cache manually. Any way that Gatsby could detect changes in required files within gatsby-node.js would be advantageous to my use case.

[amankkg]

Not sure if it counts...

Recently, I had to press Clear cache and retry deploy button in Netlify's CI during this PR - that checks turned green only after cache clean.

It started to fail with adding of prismjs and its theme CSS import in gatsby-browser.js.