Bug 170687 – test262: test262/test/language/literals/regexp/u-dec-esc.js

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Joseph Pecoraro]

Summary:
Unicode DecimalEscape with # > BackReferenceLimit should throw a SyntaxError
Non-Unicode has fallback behavior to an IdentityEscape.

Test:
js> /\8/.exec("a8b")
8

js> /\8/u.exec("a8b")
null

Expected:
The second case (unicode) should throw a SyntaxError.

Spec:

B.1.4 Regular Expressions Patterns
https://tc39.github.io/ecma262/#sec-regular-expressions-patterns

> DecimalEscape::
>   NonZeroDigit DecimalDigits(opt) [lookahead ∉ DecimalDigit]
>
> AtomEscape[U]::
>   [+U]DecimalEscape
>   [~U]DecimalEscape but only if the integer value of DecimalEscape is <= _NcapturingParens_
>   CharacterClassEscape
>   CharacterEscape[~U]

In the non-Unicode case we only go to DecimalEscape if # < capturing parens. Otherwise it falls down to character escapes (and ultimate Identity Escape).
  => non-Unicode case just escapes the character

In the Unicode case we go to DecimalEscape...

21.2.2.11DecimalEscape
https://tc39.github.io/ecma262/#sec-decimalescape

> The production DecimalEscape::NonZeroDigit evaluates as follows:
> 
>     Return the MV of NonZeroDigit.
>
> The production DecimalEscape::NonZeroDigitDecimalDigits evaluates as follows:
> 
>     Let n be the number of code points in DecimalDigits.
>     Return (the MV of NonZeroDigit × 10n) plus the MV of DecimalDigits.
>
> The definitions of “the MV of NonZeroDigit” and “the MV of DecimalDigits” are in 11.8.3.
>
> NOTE
> If \ is followed by a decimal number n whose first digit is not 0, then the escape sequence
> is considered to be a backreference. It is an error if n is greater than the total number
> of left-capturing parentheses in the entire regular expression.

The NOTE says to throw an Error if n > capturing parens.
  => Unicode case should throw an error

Notes:
- Chrome throws a syntax error for /\2/u
- Firefox throws a syntax error for /\2/u

[Joseph Pecoraro]

Seems there are some test262 tests that cover this, and we do fail them:
test262/test/language/literals/regexp/u-dec-esc.js
test262/test/language/literals/regexp/u-invalid-legacy-octal-escape.js
test262/test/language/literals/regexp/u-invalid-oob-decimal-escape.js

[Joseph Pecoraro]

Created attachment 306789 [details]
[PATCH] For Bots

[Build Bot]

Attachment 306789 [details] did not pass style-queue:


ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:898:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:899:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:900:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:901:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:902:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:903:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:904:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:905:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:906:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:907:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:908:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:909:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:910:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:911:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:912:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:913:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:914:  One space before end of line comments  [whitespace/comments] [5]
Total errors found: 17 in 6 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Joseph Pecoraro]

Created attachment 306821 [details]
[PATCH] Proposed Fix

[Build Bot]

Attachment 306821 [details] did not pass style-queue:


ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:898:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:899:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:900:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:901:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:902:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:903:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:904:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:905:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:906:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:907:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:908:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:909:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:910:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:911:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:912:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:913:  One space before end of line comments  [whitespace/comments] [5]
ERROR: Source/JavaScriptCore/yarr/YarrPattern.cpp:914:  One space before end of line comments  [whitespace/comments] [5]
Total errors found: 17 in 9 files


If any of these errors are false positives, please file a bug against check-webkit-style.

[Michael Saboff]

Comment on attachment 306821 [details]
[PATCH] Proposed Fix

r=me

[WebKit Commit Bot]

Comment on attachment 306821 [details]
[PATCH] Proposed Fix

Clearing flags on attachment: 306821

Committed r215311: <http://trac.webkit.org/changeset/215311>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.