From: jumnichi.kose@...
Date: 2017-03-23T00:49:59+00:00
Subject: [ruby-dev:50035] [Ruby trunk Bug#13352] RegExp infinite looping

Issue #13352 has been updated by jumnichi_kose (小瀬 淳一).


Thank' to @naruse

> https://regex101.com/

Your's workaround is fine.

It OK that "Somewhere in my regular expression was bad".

But,I do not understand what was wrong with my RexExp.


A similar regular expression does not fall into an infinite loop.
~~~ ruby
r = /\[((?:[^none of\]]*|other)*)\]/
a="[data]"
a[0...(-2)].scan r # => []
a.scan r # =>  [["data"]]

~~~

The other workaround was to not use "none of".
~~~ ruby
r = /(?=\W)\W?(?:(?:(?:\/\*<)?[\'\"]?([\w_\$]+)[\'\"]?(?:>\*\/\s+this)?|(this))\.(\$scope|json)|([\'\"](?:\$scope|json)[\'\"]))((\.)(inputObjects)|(\.)(spreadSheets)(?:\.[\'\"]?([\w_\$]+)[\'\"]?|\[[\'\"]?((?:[\w\s(\.)+\-\/_|!]*|\[[\w\s(\.)+\-\/_|!]\])*)[\'\"]?\])(\.)(model))\s*(?:\.[\'\"]?([\w_\$]+)[\'\"]?|\[[\'\"]?((?:[\w\s(\.)+\-\/_|!]+|\[[\w\s(\.)+\-\/_|!]*\]|\/\*[\w\s(\.)+\-\/_|!]+\*\/)+)[\'\"]?\])/

txt = ".model |,| 'anController'.$scope.inputObjects['fieldName .../* !! comment ...*/]"

txt.scan r # =>  [["anController", nil, "$scope", nil, ".inputObjects", ".", "inputObjects", nil, nil, nil, nil, nil, nil, nil, "fieldName .../* !! comment ...*/"]]

txt[0..(-2)].scan # => []

~~~

I am glad when the site that is explained where is wrong is introduced.


----------------------------------------
Bug #13352: RegExp infinite looping
https://bugs.ruby-lang.org/issues/13352#change-63738

* Author: jumnichi_kose (小瀬 淳一)
* Status: Rejected
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.3.3p222 (2016-11-21 revision 56859) [x64-mingw32],  ruby 2.2.4p230 (2015-12-16 revision 53155) [i386-mingw32]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
----------------------------------------
ruby entered an infinite loop with the following three steps.

~~~ ruby
r = /(?=\W)\W?(?:(?:(?:\/\*<)?[\'\"]?([\w_\$]+)[\'\"]?(?:>\*\/\s+this)?|(this))\.(\$scope|json)|([\'\"](?:\$scope|json)[\'\"]))((\.)(inputObjects)|(\.)(spreadSheets)(?:\.[\'\"]?([^\.\'\"\|\s,]+)[\'\"]?|\[[\'\"]?((?:[^\'\"\]\[]*|\[[^\]]*\])*)[\'\"]?\])(\.)(model))\s*(?:\.[\'\"]?([^\.\'\"\|\s,]+)[\'\"]?|\[[\'\"]?((?:[^\'\"\]\[]*|\[[^\]]*\])*)[\'\"]?\])/
txt = ".model |,| 'anController'.$scope.inputObjects['fieldName .../* !! comment ...*/"
txt.scan r
~~~

Node.js also falls into an infinite loop.
~~~ javascript
var r = /(?=\W)\W?(?:(?:(?:\/\*<)?[\'\"]?([\w_\$]+)[\'\"]?(?:>\*\/\s+this)?|(this))\.(\$scope|json)|([\'\"](?:\$scope|json)[\'\"]))((\.)(inputObjects)|(\.)(spreadSheets)(?:\.[\'\"]?([^\.\'\"\|\s,]+)[\'\"]?|\[[\'\"]?((?:[^\'\"\]\[]*|\[[^\]]*\])*)[\'\"]?\])(\.)(model))\s*(?:\.[\'\"]?([^\.\'\"\|\s,]+)[\'\"]?|\[[\'\"]?((?:[^\'\"\]\[]*|\[[^\]]*\])*)[\'\"]?\])/
var txt = ".model |,| 'anController'.$scope.inputObjects['fieldName .../* !! comment ...*/"

var s =r.exec (txt)

console.log(s)


~~~





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