Just ran into the same issue as Can't post a comment which contains -1. I did not down-vote the answer that I wanted to add a comment to. Related: Making valid use of comments containing "-1".


Workaround: since the check is just a regex and doesn't take into account if you voted, a re-write does the trick: rewrite

I wonder though, is that regex still adequate? Shouldn't the vote be taken into account at least?

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    “−1”, on the other hand, passes with flying colours. I wonder if it’s going to encourage more proper use of Unicode characters. Nov 19, 2023 at 17:05
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    'I wonder though, is that regex still adequate? Shouldn't the vote be taken into account at least?' Then someone could just comment first about their downvote and then downvote. Nov 19, 2023 at 17:06
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    See meta.stackoverflow.com/a/283953/2157772. Of note is that comments over 120 characters are exempt from the check. Nov 19, 2023 at 17:12
  • That said, I counted the characters in your attempted comment, and at 121 characters, it is supposed to be barely long enough to make it past the filter. I filed a bug on MSO. Nov 19, 2023 at 18:50
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    So it turns out that the documentation wasn't exactly correct. Your comment was a few characters too short to be exempt from the filter. In other words, an edge case. Nov 19, 2023 at 19:18
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    the downvote privilege is fairly higher than the comment privilege. taking votes into account would fail to factor in people trying to use comments to express a downvote when they can't downvote yet.
    – starball
    Nov 20, 2023 at 0:06

1 Answer 1


Keep in mind that there is an exemption that allows comments beginning with "-1" to be posted as long as there are more than 121 characters after the "-1" text. In your case, you were at 118 characters after the "-1", meaning you were just four characters short. In other words, your case was a fairly minor edge case. (This was initially documented incorrectly, but that has now been corrected.)

In my opinion, implementing the check for an existing vote wouldn't solve much. As someone commented, one can simply post the comment and then cast the vote. Also, what if someone casts a vote, then posts a comment like yours that's false-positively recognized?

Perhaps it's worth getting more data as to what length leads to fewer false positives without letting too many true positives in - but the general design as is should stay.

  • Thank you for looking into this, and pointing me to this (although I'm not supposed to say "thanks"). This whole story reminds me of the special character requirements for passwords. People had stupid passwords before. Now they have stupid passwords with special characters. Can we do better? Obviously not. Nov 20, 2023 at 7:58

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