Bug 67119 – Return value of window.onerror has inverted semantics

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Yury Semikhatsky]

In Chrome, returning 'true' from window.onerror allows the error to propagate, and returning 'false' suppresses it.

This is the inverse of the behavior in Firefox and IE, where returning 'true' suppresses the error, but returning 'false' propagates it.

(See also https://developer.mozilla.org/en/DOM/window.onerror which states: "When the function returns true, this prevents the firing of the default event handler.")

The attached html page can be used to reproduce the issue.


Original Chromium bug report: http://code.google.com/p/chromium/issues/detail?id=92062

[Yury Semikhatsky]

Ian is going to make the spec match behavior of IE and FF, WebKit implementation should also be changed.

[Yury Semikhatsky]

Created attachment 105490 [details]
Patch

[WebKit Review Bot]

Comment on attachment 105490 [details]
Patch

Attachment 105490 [details] did not pass chromium-ews (chromium-xvfb):
Output: http://queues.webkit.org/results/9563186

New failing tests:
fast/events/window-onerror13.html

[Darin Adler]

I think the test coverage here is not sufficient. I’d like to see tests covering the case where the function does not have a return statement. And cases where event.preventDefault() is called.

[Yury Semikhatsky]

Committed r94061: <http://trac.webkit.org/changeset/94061>

[Yury Semikhatsky]

(In reply to comment #4)
> I think the test coverage here is not sufficient. I’d like to see tests covering the case where the function does not have a return statement. And cases where event.preventDefault() is called.

I'll add new tests in a separate patch shortly.

[Csaba Osztrogonác]

It made 3 tests fail on the SL bot and on the Qt bot. (maybe on other bots too) Reopen to fix the bug and/or update tests. (I don't know if the new results are correct or not.)

--- /Volumes/Data/WebKit-BuildSlave/snowleopard-intel-release-tests/build/layout-test-results/fast/workers/shared-worker-script-error-expected.txt 
+++ /Volumes/Data/WebKit-BuildSlave/snowleopard-intel-release-tests/build/layout-test-results/fast/workers/shared-worker-script-error-actual.txt 
@@ -1,4 +1,5 @@
 CONSOLE MESSAGE: line 12: ReferenceError: Can't find variable: generateError
+CONSOLE MESSAGE: line 18: ReferenceError: Can't find variable: generateError
 Test SharedWorker script error handling functionality. Should print a series of PASS messages, followed with DONE.
 
 SUCCESS: unhandled error generated


--- /Volumes/Data/WebKit-BuildSlave/snowleopard-intel-release-tests/build/layout-test-results/http/tests/security/cross-origin-script-window-onerror-redirected-expected.txt 
+++ /Volumes/Data/WebKit-BuildSlave/snowleopard-intel-release-tests/build/layout-test-results/http/tests/security/cross-origin-script-window-onerror-redirected-actual.txt 
@@ -1,3 +1,4 @@
+CONSOLE MESSAGE: line 1: SyntaxError: Expected an identifier but found 'sensitive' instead
 Test that window.onerror won't reveal any potentially sensitive script content if the latter is loaded from a different domain after a redirect. The test passes if you don't see any data from the linked resource. Bug 52903.
 
 window.onerror message: Script error. at : 0



--- /Volumes/Data/WebKit-BuildSlave/snowleopard-intel-release-tests/build/layout-test-results/http/tests/security/cross-origin-script-window-onerror-expected.txt 
+++ /Volumes/Data/WebKit-BuildSlave/snowleopard-intel-release-tests/build/layout-test-results/http/tests/security/cross-origin-script-window-onerror-actual.txt 
@@ -1,3 +1,4 @@
+CONSOLE MESSAGE: line 1: SyntaxError: Expected an identifier but found 'sensitive' instead
 Test that window.onerror won't reveal any potentially sensitive script content if the latter is loaded from a different domain. The test passes if you don't see any data from the linked resource. Bug 52903.
 
 window.onerror message: Script error. at : 0

[Csaba Osztrogonác]

Fixed in http://trac.webkit.org/changeset/94066