gatsby-plugin-canonical-urls: root page canonical url contains trailing slash when trailingSlash === never

[techfg]

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

When trailingSlash is set to never, gatsby-plugin-canonical-urls generates a canonical url for the default page that ends in a trailling slash (all other pages are correct).

The issue seems to stem from https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-canonical-urls/src/gatsby-ssr.js#L10 where it always adds pathname to the parsed url.

Reproduction Link

https://codesandbox.io/p/sandbox/canonical-urls-contains-trailingslash-l7f9sf

Steps to Reproduce

1. Set trailingSlash to never in gatsby-config.js
2. Build site (gatsby develop)
3. Inspect HTML head in default page (`/')

Note

If using Codesandbox repro, you may need to open the sandbox URL in a separate tab to open dev tools

Expected Result

The default page canonical url should not contain a trailing slash

Actual Result

The default page canonical url does contain a trailing slash

Environment

System:
    OS: Linux 5.15 Debian GNU/Linux 11 (bullseye) 11 (bullseye)
    CPU: (2) x64 AMD EPYC
    Shell: 5.8 - /bin/zsh
  Binaries:
    Node: 18.16.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 9.5.1 - /usr/local/bin/npm
  npmPackages:
    gatsby: ^5.11.0 => 5.11.0
    gatsby-plugin-canonical-urls: ^5.11.0 => 5.11.0

Config Flags

N/A

[techfg]

Apologies, just found the closed issue #37536 which references #34205 (reply in thread) where this was discussed. The release notes from 4.7 indicate that any path with a / when never is configured will 301 redirect which is the behavior I experience. Thinking this through some more and validating behavior, confirmed that 301 is returned when path ends in / EXCEPT for the default page where only window.location.href is "adjusted" to remove the slash which makes sense since root paths can't be redirected.

The main concern was making sure everything is consistent across core gatsby & the plugins when trailingSlash is never which it does appear to be. I should have looked more closely before opening this issue, apologies again.

Closing this out.