Fix regex for uBO (addresses https://github.com/DandelionSprout/adfil…

[Yuki2718]

…t/discussions/163#discussioncomment-4117315)

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• This is not an ad/bug report;
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• My changes do not break web sites, apps and files structure.

What problem does the pull request fix?

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• Missed ads or ad leftovers;
• Website or app doesn't work properly;
• AdGuard gets detected on a website;
• Missed analytics or tracker;
• Social media buttons — share, like, tweet, etc;
• Annoyances — pop-ups, cookie warnings, etc;
• Filters maintenance.

What issue is being fixed?

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DandelionSprout/adfilt#163 (reply in thread)
It turned out uBO requires - to be escaped if it's at the end.

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[Alex-302]

Our regexes are valid. The most of filters have rules with -] in regexes.

[Yuki2718]

Then how about NOT_PLATFORM(ext_ublock)? uBF has counterparts of these regex rules anyway.

The most of filters have rules with -] in regexes.

Yeah, found on Annoyances as well and I won't fix them all. Not too serious issue.

[scripthunter7]

I think that this issue can also occur in the case of many filter lists, since -] is a valid regex, so this PR does not solve the problem itself. Maybe a better solution would be to replace -] with \-] internally before the regexp is passed to the analyzer.

[Yuki2718]

So move to https://github.com/AdguardTeam/FiltersCompiler ?

[scripthunter7]

So move to https://github.com/AdguardTeam/FiltersCompiler ?

I think this issue is related to the uBlock parser:
https://github.com/gorhill/uBlock/blob/master/src/js/static-filtering-parser.js#L26

I guess uBO also uses lists that don't go through the AG's Filters Compiler, and those lists can easily use -] in regexps.

[Yuki2718]

@gorhill

[scripthunter7]

By the way, here is the problematic part in the analyzer library:

https://github.com/foo123/RegexAnalyzer/blob/807f106914ed8b650d792d7a158f63040fd579c3/src/js/Regex.js#L1079-L1099

When line 1094 checks whether the currently iterated character is a hyphen, you need a lookahead in which you check whether the next character sequence is whitespaces + closing bracket.

But this seems like a rather outdated / low documented / low tested library, I think there are much more modern ones.

[scripthunter7]

Without any warranty, something like this: https://github.com/scripthunter7/RegexAnalyzer/blob/master/src/js/Regex.js

[gorhill]

We discussed this a long time ago, I said I would fix this eventually, we should not bother AdGuard's repo just because I take long to fix stuff which is one thing among all the rest I need to work on.

[danny0838]

@gorhill About the commit (I cannot leave a comment in the commit page, seems to be an issue of GitHub?):

I wonder if modifying the regex.js library without populating to the upstream is a good idea. Also this doesn't seem to deal with the [-abc] case.

I would recommend preprocessing regex strings by escaping starting and ending - with \- before sending to the analyzer instead, until the library is fixed.

[krystian3w]

(I cannot leave a comment in the commit page, seems to be an issue of GitHub?)

That is limitation to disable open issues in repository of add-on code.

Sometimes someone can turn it off - once I managed to give a reaction to PR and after a few days someone blocked it (undo/new actions was down).