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I discovered a strange, blank link in this user's Top Network Posts:

Top Network Posts, with one link to a blank post on Meta Stack Exchange that's scored 13

The above link and screenshot are of the user's Unix & Linux site profile, but this issue can be reproduced on any of the user's site profiles other than Meta Stack Exchange (as the blank post appears to be on this site, and posts from the same site are excluded).

The link seems to go to https://meta.stackexchange.com/questions/-2147482643/330386#330386, which features a really negative question ID (close to the lowest value that can be represented by a 32-bit signed integer, specifically -(2^31) + 1005), and lacks the title in the URL that is present in all of the other links. It leads to a 404 error.

Going to the actual answer 330386 seems to go to an actual answer on a question migrated to this site, which happens to have a score of 13 (as of the time this was asked).

Why is the question ID incorrect here? Based on the duplicates, it seems that this affects posts (both questions and answers) that were migrated from other sites: somehow, the question ID seems to be getting messed up.

Update: It looks like the above linked user has deleted their account on this site, so the issue cannot be reproduced on the profile I originally reported. It can, however, be reproduced on this one. The errant link in that profile is https://ell.stackexchange.com/questions/-2147480236/184031#184031, and the errant question ID seems to also be close to the lowest possible 32-bit signed integer, -(2^31) + 3412.

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  • 1
    Related / duplicate(?): Top network post URL bug - that's also a migrated question with a question ID close to -2^31. – Glorfindel Aug 15 '19 at 6:57
  • It's a good idea to add the actual date because weeks or months from now, and if the post is edited another time, users won't know which month (or year) the update refers to. – Mari-Lou A Nov 20 '19 at 7:12
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    From what I can understand, the link on the EL&Uer's profile appears to point to a deleted post on ELL,which leads to a 404 page, even though I have enough rep to see deleted posts on both sites. – Mari-Lou A Nov 20 '19 at 7:16
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+200

This issue has been fixed.

Details:

  • The specific issue occurred when an answer was migrated along with a question.
  • Due to the buggy mechanics here the post lost its associate with the parent post on a network post aggregation table that we use for things like querying Top network posts (the actual associate with the migrated parent post in the Posts table was fine).
  • If that answer later got enough votes to show up on the user's Top network posts, the url was generated with the wrong parent post Id (that big ugly negative number) that had been saved in the aggregation table.
  • Changes:
    • The actual bug has been fixed
    • Additional safeguards have been put into place to prevent bad data from being inserted in this way (and to log it if this is attempted)
    • All 4,447 posts affected by this have had their data corrected in the relevant network aggregation table, so any user where this error was showing up should now have correct links in their Top network posts list (this is cached, so may need a few minutes to show up everywhere)

migrate a question
answer receives much esteem
link built properly

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