27

I came across this weird tag accidentally. SO claims there are 67488 questions tagged with it. Is it a bug or a feature?

The screenshot:

enter image description here

13
  • Seems to be gone now.
    – user50049
    Feb 8, 2012 at 15:32
  • @TimPost Hm. I'm still seeing the thing on the Questions page in Related Tags.
    – Costique
    Feb 8, 2012 at 15:43
  • I see 2,626,020 questions tagged...o.O
    – tombull89
    Feb 8, 2012 at 15:47
  • Another weird thing is that I cannot find the tag using search or filtering the Tags page.
    – Costique
    Feb 8, 2012 at 15:49
  • Possible duplicate: meta.stackexchange.com/questions/100841/…
    – Costique
    Feb 8, 2012 at 15:57
  • @Costique Yup, but I'm not inclined to close this, as this seems to be one of those bugs. Ya know, the kind that has been linked to Tourette Syndrome.
    – user50049
    Feb 8, 2012 at 16:01
  • @TimPost: I'm seeing this in my list as well...
    – animuson StaffMod
    Feb 8, 2012 at 17:15
  • This is strange, I can't reproduce it.
    – user50049
    Feb 8, 2012 at 17:17
  • @TimPost It's still there for me, though. Its number of questions is fluctuating as if it's a real thing.
    – Costique
    Feb 8, 2012 at 17:21
  • 1
    Wait, reproduced, look at the related tags between SQL and Ruby On Rails (thanks @Fabian)
    – user50049
    Feb 8, 2012 at 17:22
  • @TimPost: I also notice that specific tag has a title="show questions tagged '*~294'" whereas all the other tags in that list have a title=""...
    – animuson StaffMod
    Feb 8, 2012 at 17:25
  • @TimPost Yay! That's it. I wonder if there's a valid tag which has the exact same number of questions. Could a valid tag be renamed/aliased?
    – Costique
    Feb 8, 2012 at 17:31
  • Also found in the Tagged Questions for c++, which shows *~294 × 12836.
    – kennytm
    Feb 8, 2012 at 19:58

2 Answers 2

17

We had a secret sub-domain that we used to test features required for facebook.stackoverflow.com and recently removed it.

This tag is just some stale data that will be purged in a few hours, after peak traffic.

3
  • 12
    And you would have gotten away with it, if it weren't for us meddling kids!
    – user50049
    Feb 8, 2012 at 20:15
  • 3
    shakes fist angrily Feb 8, 2012 at 20:16
  • 1
    Thanks for fixing it. Yeah, Facebook is evil, it's that bad.
    – Costique
    Feb 9, 2012 at 4:34
8

I can't say why the tag was appearing in that list, but it seems to be a valid combination of wildcards. The * character is a client-side wildcard and ~ is a server side wildcard. The server-side wildcard has the additional restriction that you need at least 4 characters in your pattern or it will be rejected.

So what this tag pattern means is

*   :match anything client-side
~   :match anything server-side
294 :match 294

The last match is needed because of the server-side 4 character limit, if you remove the last character the pattern is rejected. If you use a number there that doesn't exist in any tag this part seems to be ignored entirely and you're left with a pattern that matches every question on the site.

For tag the client-side wildcard is automatically replaced by the server-side wildcard, so this pattern is equivalent to ~~294.

That this URL works is probably a feature, but this tag certainly shouldn't appear in any tag listings.

1
  • Thanks for the explanation. Looks like a bug. I wonder where the number comes from.
    – Costique
    Feb 8, 2012 at 15:55

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