1890466 - EmailInputType::PunycodeEncodeEmailAddress does not check for hyphen

Status: NEW

(Core :: DOM: Forms, defect)

Description

[Henri Sivonen (:hsivonen) (away from Bugzilla until 2026-04-13)]

Per https://html.spec.whatwg.org/#valid-e-mail-address , EmailInputType::PunycodeEncodeEmailAddress should check that labels don't start or end with a hyphen, but we don't currently check for that. (We should probably check what other browser do before checking it. Trailing hyphens do exist in labels that are not overseen by ICANN. See bug 1184059.)

Comment 1

[Leo Tenenbaum [:ltenenbaum]]

Labels starting/ending with hyphens are still considered as suffering from a type mismatch (in Firefox as well as WebKit and Chromium), so I guess the question is just whether it should also be considered as suffering from bad input and whether value should still be puny-encoded or not?
Chromium seems to never set badInput for email inputs (even when puny-encoding fails), and only puny-encodes value if it is a valid email address. (And there is also the question of whether two consecutive dots should be checked for.)

Comment 2

[Henri Sivonen (:hsivonen) (away from Bugzilla until 2026-04-13)]

We should port https://github.com/hsivonen/emaildemo/blob/main/src/lib.rs to Gecko. See long discussion in https://github.com/whatwg/html/pull/10522 and https://github.com/whatwg/html/issues/4562