A user reports that he has received the confirmation email email in rough mode, with a broken link. The link was displayed this way:
https://fr.wikipedia.org/wiki/Special:ConfirmEmail/[here is the token]
Users are redirected to https://fr.wikipedia.org/wiki/Special, which is not really helpful. It this happen often, we may have lost a lot of new users.
If I get it correctly it was in plain text format, and not HTML format.
In that case there is not much we can do if people use broken email clients which don't understand that a colon can be part of a valid URL...?
Maybe add < and > on each side of the URL? It usually helps to keep the link consistant.
Could the original reporter send a plain text email to themselves that include a line such as <https://www.example.com/Special:Example/123> to confirm that this would help, and tell us which exact email application was used to read the email which was problematic?
The one created by the email provider, sunrise.ch. If they have the same quality as French providers, it explains a lot. :/
On many services, there is a note at the end of the email, saying "copy the entire email in your browser if it is not working". It may be a way to have less failure, but I'm not sure it can be a fix.
Maybe : could be converted to %3A but I'm not convinced, because T72245: enotif watchlist notification emails include percent-encoded URLs in body for non-ASCII scripts, should use normalized titles instead.
Similar issues are T40265: Links in emails: Parentheses ( or ) not recognized as part of URL - brackets should be URL-encoded and T50940: Punctuation like ".", "?" and "!" at the end of page title in links not interpreted as part of the URL by various applications.