Trailing slash is not enforced when editing the path for a subdirectory site in multisite

[simonwheatley]

It is possible to edit an existing subdirectory site so that the path does not end in a trailing slash, this causes the subdirectory site in question to have an inaccessible home URL.

To reproduce:

• Create a multisite network in subdirectory mode
• Create a new subdirectory site
• Visit the subdirectory site successfully
• Edit the site to change the path so there is no trailing slash
• You should be unable to visit the subdirectory site now

[johnbillion]

Can the same thing can happen with the leading slash?

[simonwheatley]

Ensures trailing and prefixing slash on path

[simonwheatley]

Good spot, yes it can. Even more terminal issues there.

Patch amended to also add a prefixing slash.

[simonwheatley]

Attaching a diff showing a different approach, this time I'm using sanitise title and then adding the slashes manually. This approach allows us to check for multiple slashes which might have been added as well.

Also attaching some tests for this issue.

My first unit tests for WordPress, so I'd welcome any feedback. :)

[simonwheatley]

New test method for multisite to test the path is correctly sanitised and slashed

[simonwheatley]

Use sanitize_title and manually add prefixing and trailing slash for subdir site path

[jeremyfelt]

Related #18117 (almost duplicate). It would be good to make sure both of these solutions go hand in hand.

[jeremyfelt]

@simonwheatley - I have feedback on process. :) The new develop.svn repository allows for the creation of a single patch that includes both the src and tests changes. It's much easier to apply and test that. Just run svn diff from the root of develop.svn's trunk.

[jeremyfelt]

I'd like to work on getting this in for 4.1. We should refresh the patch to match the unit test changes in #29896.

[earnjam]

18117.4.diff:ticket:18117​ appears to solve the trailing slash problem described in this ticket.

[johnbillion]

Related: #30417

[jeremyfelt]

In 31155:

Enforce leading and trailing slashes on paths updated with update_blog_details()

In multisite, core expects the stored value for a site's path to have leading and trailing slashes. When these slashes are missing, it becomes impossible to visit the site.

This enforces proper /path/ creation in update_blog_details(), most likely used when updating an existing site through site-info.php.

Props earnjam, simonwheatley.

Fixes #18117. Fixes #23865.