Gatsby Head API doesn’t react on context change

[juliavorcakova]

Preliminary Checks

• This issue is not a duplicate. Before opening a new issue, please search existing issues: https://github.com/gatsbyjs/gatsby/issues
• This issue is not a question, feature request, RFC, or anything other than a bug report directly related to Gatsby. Please post those things in GitHub Discussions: https://github.com/gatsbyjs/gatsby/discussions

Description

I need to share a state between body and head. I’m trying to achieve it with context and Gatsby Head API, but Gatsby Head doesn’t seems to react on context changes. It reads the initial state correctly, but after the context is updated it doesn’t rerender.

Reproduction Link

https://codesandbox.io/p/sandbox/sad-hofstadter-vl7jl8?file=%2Fsrc%2Fpages%2Findex.js%3A22%2C38

Steps to Reproduce

1. start the app https://vl7jl8-8000.csb.app/
2. open browser console
3. click on 'update context' button
4. observe that after clicking the button, there are no logs from Gatsby Head (head context: {contextValue}) nor changes in "context-test" meta tag

Expected Result

Head rerenders when context value changes.

Actual Result

Head doesn’t react on context value change.

Environment

System:
    OS: Windows 10 10.0.19045
    CPU: (8) x64 Intel(R) Core(TM) i7-10610U CPU @ 1.80GHz
  Binaries:
    Node: 18.17.0 - C:\Program Files\nodejs\node.EXE
    npm: 9.6.7 - C:\Program Files\nodejs\npm.CMD
  Languages:
    Python: 3.10.11
  Browsers:
    Edge: Spartan (44.19041.1266.0), Chromium (115.0.1901.200)
  npmPackages:
    gatsby: ^5.12.1 => 5.12.1
    gatsby-plugin-manifest: 4.24.0 => 4.24.0
    gatsby-plugin-react-helmet: 5.25.0 => 5.25.0
    gatsby-plugin-react-helmet-canonical-urls: 1.4.0 => 1.4.0

Config Flags

No response