Thomas Wisniewski Assignee
	Description • 8 years ago

The XHR spec states that GetAllResponseHeaders() should return the empty string on errors (we're in a "network error" response state, and those are stated to not have any headers). Chrome already passes the relevant web platform test:

http://w3c-test.org/XMLHttpRequest/xmlhttprequest-network-error.htm

	Thomas Wisniewski Assignee
	Comment 1 • 8 years ago

Here's a patch which passes the test.

Try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=dfbd3de4a26d

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 2 • 8 years ago

Comment on attachment 8770984 [details] [diff] [review]
1286744-return_empty_string_for_getAllResponseHeaders_if_errors.diff

Where does the spec actually say that. fetch is so unreadable spec that finding anything there is rather hard.

	Olli Pettay [:smaug][bugs@pettay.fi]
	Comment 3 • 8 years ago

Ah, this "A network error is a response whose status is always 0, status message is always the empty byte sequence, header list is always empty, body is always null, and cache state is always "none". "

	Thomas Wisniewski Assignee
	Comment 4 • 8 years ago

Thanks, I'll try to be extra-clear with my wording next time to spare the extra reading exercise.

Requesting checkin.

	Pulsebot
	Comment 5 • 8 years ago

Pushed by ryanvm@gmail.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/54af298e7b99
Return the empty string from GetAllResponseHeaders() if the XHR failed. r=smaug

	Carsten Book [:Tomcat]
	Comment 6 • 8 years ago
bugherder

https://hg.mozilla.org/mozilla-central/rev/54af298e7b99

	Kohei Yoshino [:kohei]
	Comment 7 • 8 years ago

Posted the site compatibility doc: https://www.fxsitecompat.com/en-CA/docs/2016/network-error-for-async-xhr-now-fires-error-event-instead-of-throwing-getallresponseheaders-will-be-empty/

	Jean-Yves Perrier [:teoli]
	Comment 8 • 8 years ago

I have precised the return value of 
https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/getAllResponseHeaders
and a mention in
https://developer.mozilla.org/en-US/Firefox/Releases/50#DOM_and_HTML_DOM