Bug 50570 – REGRESSION (r73065?): A regex no longer works

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Francisco Tolmasky]

Created attachment 75703 [details]
URL regex that matches in FF, IE, and Safari but not nightlies.

After this change I believe: http://trac.webkit.org/changeset/73065, regexes that were succeeding before (and succeed in other browsers) now no longer match. I have included a reduction.

In the reduction I've attached, Safari logs the following:

["file:///Users/tolmasky/Desktop/HelloWorld/index.html", "file", "//", "", undefined, undefined, undefined, "", undefined, "/Users/tolmasky/Desktop/HelloWorld/index.html", undefined, undefined]

But the nightly logs "null".

[Geoffrey Garen]

<rdar://problem/8739603>

[Michael Saboff]

*** Bug 50673 has been marked as a duplicate of this bug. ***

[Michael Saboff]

Created attachment 76077 [details]
Patch to fix linking of parentheses tail code.

[Alexey Proskuryakov]

+        Changed the handling of adjacent parentheses backtracks in two ways.
+        First, only outer most paren backtracks default to back tracking
+        to the "next character" looping code.  Second, added a jump around 
+        backtracks that fall through to the next backtrack where the
+        second backtrack has some greedy processing before the backtracking
+        from outside the parentheses code.
+        https://bugs.webkit.org/show_bug.cgi?id=50570

A somewhat more readable and common format would be:

+        REGRESSION (r73065): A regex no longer works
+        https://bugs.webkit.org/show_bug.cgi?id=50570
+
+        Changed the handling of adjacent parentheses backtracks in two ways.
+        First, only outer most paren backtracks default to back tracking
+        to the "next character" looping code.  Second, added a jump around 
+        backtracks that fall through to the next backtrack where the
+        second backtrack has some greedy processing before the backtracking
+        from outside the parentheses code.

[Michael Saboff]

Created attachment 76089 [details]
New Patch with redundant {increment/decrement}ParenNestingLevel calls

[Gavin Barraclough]

Hi Michael,

(1) please fix the change log comment per alexey's request.
(2) please remove the superfluous indent.
(3) please switch JumpList -> Jump.
(4) please comment the new check, with a simple example.

cheers,
G.

[Michael Saboff]

Created attachment 76111 [details]
Patch addressing reviewers comments

Note that I also cleaned up ALL of the extra whitespace in the file JavaScriptCore/yarr/RegexJIT.cpp.  Therefore the resulting patch is large.

[Michael Saboff]

Committed r73640: <http://trac.webkit.org/changeset/73640>