Regression in Upgrade header handling

[bnoordhuis]

See nodejs/node#627 and nodejs/node#628 for background.

In a nutshell, 2.4.1 doesn't like uncommon Upgrade header formats. The regression test in nodejs/node#628 is a good example.

/cc @indutny

[mscdex]

"Uncommon" here means "invalid" since both Connection: upgrade and Upgrade: ... are required according to RFC 7230 (second paragraph). Unless we're wanting to support broken clients.... but are there real cases of that out in the wild where clients only send Upgrade?

On a semi-related note, Upgrade headers must also be ignored if received from an HTTP 1.0 client. I'm guessing this should be handled at the parser layer too?

[indutny]

@mscdex all of your comment is correct, except that I have introduced an unintentional behavior change. This means that there could be some bug that I have overlooked.

[indutny]

Nah, I see now where this behavior was introduced 091ebb8 . @bnoordhuis on a second thought I think that @mscdex is right about it as the change was quite intentional.

@bnoordhuis Why do we want to support this?

[indutny]

Not a regression.