1664426 - Intermittent /fetch/corb/script-resource-with-json-parser-breaker.tentative.sub.html | CORB-blocks <random> that starts with the following JSON parser breaker - assert_unreached: Empty body of a CORS-blocked response shouldn't trigger syntax errors

Status: RESOLVED INCOMPLETE

(Core :: DOM: Networking, defect, P5)

Description

[Treeherder Bug Filer]

Filed by: hskupin [at] mozilla.com
Parsed log: https://treeherder.mozilla.org/logviewer.html#?job_id=315315222&repo=try
Full log: https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/NRk78eexQoikQ-4QwVJ1FQ/runs/0/artifacts/public/logs/live_backing.log

---

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

This kind of failure will start to happen once my patch on bug 1612831 lands and gets rid of an error in the wptrunner. It happens for nearly all the combinations of MIME type and syntax error.

Also there is at least one timeout that happens for image/png and maybe also other image and application types. The reason for those is that such MIME types aren't allowed for scripts, and the script is not getting loaded. That's clearly visible in the webconsole.

Here an excerpt:

Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:3
The script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=text/json&body=)%5D%7D%27” was loaded even though its MIME type (“text/json”) is not a valid JavaScript MIME type.
script-resource-with-json-parser-breaker.tentative.sub.html
Uncaught SyntaxError: expected expression, got ')'
sniffable-resource.py:1
The script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=text/json&body=%7B%7D%26%26” was loaded even though its MIME type (“text/json”) is not a valid JavaScript MIME type.
script-resource-with-json-parser-breaker.tentative.sub.html
Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:2
The script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=text/json&body=%7B%7D%20%26%26” was loaded even though its MIME type (“text/json”) is not a valid JavaScript MIME type.
script-resource-with-json-parser-breaker.tentative.sub.html
Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:3
The script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=text/plain&body=)%5D%7D%27” was loaded even though its MIME type (“text/plain”) is not a valid JavaScript MIME type.
script-resource-with-json-parser-breaker.tentative.sub.html
Uncaught SyntaxError: expected expression, got ')'
sniffable-resource.py:1
The script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=text/plain&body=%7B%7D%26%26” was loaded even though its MIME type (“text/plain”) is not a valid JavaScript MIME type.
script-resource-with-json-parser-breaker.tentative.sub.html
Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:2
The script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=text/plain&body=%7B%7D%20%26%26” was loaded even though its MIME type (“text/plain”) is not a valid JavaScript MIME type.
script-resource-with-json-parser-breaker.tentative.sub.html
Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:3
Uncaught SyntaxError: expected expression, got ')'
sniffable-resource.py:1
Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:2
Uncaught SyntaxError: expected expression, got '&&'
sniffable-resource.py:1:3
Script from “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=image/png&body=)%5D%7D%27” was blocked because of a disallowed MIME type (“image/png”).
script-resource-with-json-parser-breaker.tentative.sub.html
Loading failed for the <script> with source “http://www1.web-platform.test:8000/fetch/corb/resources/sniffable-resource.py?type=image/png&body=)%5D%7D%27”. script-resource-with-json-parser-breaker.tentative.sub.html:1:1

Anne, do you know what's going on here? I assume there is missing feature parity in Firefox and for now we should just add the expected failures and timeouts? After landing my patch it might be easier to investigate and fix the problem. Thanks.

Comment 2

[Anne (:annevk)]

We already fail fetch/corb/script-resource-with-json-parser-breaker.tentative.sub.html as far as I can tell and do not implement CORB (nor plan to, see bug 1532642). Given that, it's a bit hard to evaluate what changed as a result of your patch and whether that is problematic or not. In principle though we should not have a difference before/after Fission.

Comment 3

[Intermittent Failures Robot]

17 failures in 3410 pushes (0.005 failures/push) were associated with this bug in the last 7 days.

Repository breakdown:

• try: 17

Platform breakdown:

• macosx1014-64: 2
• windows10-64-qr: 3
• linux1804-64-qr: 4
• windows7-32: 2
• windows10-64: 2
• linux1804-64: 1
• android-em-7-0-x86_64: 2
• linux1804-64-asan: 1

For more details, see:
https://treeherder.mozilla.org/intermittent-failures.html#/bugdetails?bug=1664426&startday=2020-09-07&endday=2020-09-13&tree=all

Comment 4

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Yes, we fail in terms of ERROR but which is a harness error. With my patch it will start failing with FAIL, TIMEOUT, and NOTRUN. The latter only happens because the image/png case never finishes due to the failure as mentioned above.

Comment 5

[Jens Stutte [:jstutte]]

Bulk closing some old intermittents.