Bug 127177

Summary: Yarr interpreter reports non-match instead of throwing when bailing out
Product: WebKit Reporter: Till Schneidereit <till>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: bzbarsky
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
URL: https://bugzilla.mozilla.org/show_bug.cgi?id=953013

Description Till Schneidereit 2014-01-17 09:53:23 PST 
The Yarr interpreter contains a limit on how many attempts are made to match disjunctions. When this limit is reached, a bailout with JSRegExpErrorHitLimit happens. This bubbles up and is returned as the result of JSC::Yarr::interpret, the caller of which treats it the same as JSRegExpNoMatch.

In SpiderMonkey, we changed things to throw an exception in this case; see the patch in the linked bug.
Comment 1 Boris Zbarsky 2014-01-17 11:42:12 PST 
Note that this leads to incorrect behavior in Safari.  For example:

  /^a(\w+)+b/.test("axbxxxxxxxxxxxxxxxxxxxx")

returns false in Safari, whereas the correct value is true.  Chrome gets this right.