[validator] Multiline "on:tap" does not trigger ARIA validation

[RoganMurley]

What's the issue?

If an on attribute is multiline then ARIA validation isn't triggered. ARIA validation should be triggered even if the on attribute is multiline.

How do we reproduce the issue?

This Playground should be invalid...

...like this Playground is.

[amaltas]

This regex match is not matching multiline values. https://github.com/ampproject/amphtml/blob/master/validator/validator-main.protoascii#L4839

The fix is to change the pattern to something like "tap:(.|\n)*" which match newlines. However this fix won't make it until we identify if a large number of existing valid amp documents will get invalidated due to the missing attribute which was not detected due to this bug.

Keeping this issue open but low priority.

[amaltas]

cl/355064647 for internal reference.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.