Incorrectly removing trailing slash from URL

[sb-relaxt-at]

From my understanding removing any trailing slash in rebuildURL is not correct:

silverstripe-externalurlfield/src/ExternalURLField.php

Line 158 in 02436af

return rtrim(http_build_url($defaults, $parts), "/");

The trailing slash could be part of a fragment or query, e.g.:

• http://www.example.org/#foo/
• http://www.example.org/?foo=/

In these cases we have no knowledge whether or not the trailing slash is meaningful. But even if the trailing slash is part of the path, it might be relevant, as the webserver could serve two different pages (compare Google Webmasterblog). Therefore I would suggest removing the rtrim call.

[JamesDPC]

I encountered this issue when an external site redirected to another external site if the trailing slash was not present.

eg.:

• I entered https://example.net/ into the field, saved the record
• The field stored https://example.net
• The URL clicked is https://example.net
• Due to example.net redirect rules, the visitor ends up at https://example.com
• The visitor expected to stay at https://example.net

Removing the trailing slash is unexpected and seems arbitrary, could this be updated and released? It's a trivial change.