Improve behavior after publishing a new version causes `/latest/` to lose children about docs.rs HOT 2 OPEN

I like the idea.
we probably would just have to define a new error type & page with the necessary information.

Also note another option:
when you switch platforms in a release and the other platform doesn't have the current file, we convert the URL into a search and run a rustdoc search on the other platform. Not sure if this would be a useful other option for this 404 page.

from docs.rs.

@kpreid Here is a suggestion.

How to Solve the Issue

1. Design a New 404 Error Page:

   • Information Display: The 404 page should clearly state that the requested resource does not exist but that the package and version are valid.
   • Navigation Options: Provide direct links to:
     • The root documentation page for the current version.
     • A page to browse other versions of the package.
   • Previous Version Lookup (Stretch Goal):
     • Implement a feature to search for the most recent previous version where the resource was available and link to that version.

2. Implementing Navigation Links:

   • Root Documentation Link: This can be achieved by extracting the base URL from the request and appending the version to navigate to the root documentation for that version.
   • Version Browsing Link: Provide a link to the package’s main page where users can select different versions to view.
   • Previous Version Lookup:
     • Implement logic to search through the version history of the package to find the last version where the resource existed. This might involve querying metadata or change logs.

Example 404 Page Design

Here’s a conceptual design for the improved 404 error page:

404 Not Found

The requested resource does not exist in the current version of the package.

Package and Version Information:

• Package: example
• Version: 0.18.0

Navigation Options:

• Return to the root documentation for this version
• Browse other versions of the package

(Optional) Previous Version with Resource:

• The requested resource was available in version 0.17.0. [View documentation for this version]

from docs.rs.