[ruby-core:85229] [Ruby trunk Bug#14418] ruby 2.5 slow regexp execution

Issue #14418 has been updated by shevegen (Robert A. Heiler).


> You have to insert a blank line before 

I also often just insert four ' ' space characters before the code
I want to add; no idea if it is correctly interpreted but it seems
to work on both github and ruby-lang.org, so I tend to use it. :D

To the regexp performance, I have no idea if it is a bug or not,
but I think either way, it may be helpful to have some test code
that can test different regexps and correlate it with the "expected
speed outcome". That way issue requests like this could help people
before they report a (potential) issue, to see whether everything
works as-is or some kind of bug exists.

Since you use "ß", let me ask you - what encoding do you use within
the script? Possibly UTF-8? Have you tested if some ISO-encoding
makes a difference in regards to speed?

----------------------------------------
Bug #14418: ruby 2.5 slow regexp execution
https://bugs.ruby-lang.org/issues/14418#change-69978

* Author: jakub.wozny (Jakub Woźny)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.5
* Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN
----------------------------------------
I have simple regexp that performing very slow.
~~~ ruby
"fußball "*20 =~ /^([\S\s]{1000})/i
~~~

It works fast if I remove ```\i``` flag. I figured out that is also depends on string length or on quantifier value (in this case it is ```{1000}```).
When you remove ```ß``` form the string it also works fast.

I tested on 2.3.1, 2.4.3 and 2.5.0.

I'm not sure it is a bug or it just works that way.



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