Searching for google-collections takes me to https://stackoverflow.com/questions/tagged/google-collections, and in the search box [google-collections] gets displayed (note the brackets). Pressing enter (the searching has changed from full-text search to tag search) leads to https://stackoverflow.com/questions/tagged/guava, and the search term has changed to [guava].

So there's a search term replacement chain google-collections -> [google-collections] -> [guava], which is a bit strange. First, a text gets replaced by a tag, and then, the tag gets replaced by another one due to aliasing. This should probably happen in one step.

Note that, despite the aliasing, the search results differ. ColinD (the guava guy answering most guava-related questions here) is not sure, if retagging should happen. Adding the [guava] tag to all questions tagged [google-collections] is not possible, since some of them already have the maximum tag count. Maybe adding it wherever possible and replacing otherwise could be the way to go?

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    voting to reopen, since this isn't a SO-specific issue - just a general search behaviour thing. Jul 30, 2014 at 4:03
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    Search has changed a lot since this was first posted, but this complete chain is not reproducible now...searching "google-collections" won't switch to a tag search anymore. The tag synonyms work as intended.
    – Laura
    Jul 31, 2014 at 15:46

1 Answer 1


There's a synonym of . However, the tags have not been merged - thus there exist questions that have .

As such, if you go to the first tag normally, it will take you to see the questions that still have that tag. That's what happens in the first search replacement. However, as per normal tag search protocol, if you search for the child of a synonym, it will instead search for the synonym. That's what happens in the second search replacement.

If they are true synonyms, then the tags should be merged, which will replace all instances of with , and so the first search replacement will henceforth no longer occur. If they are not correct synonyms, then the synonym must be broken, which will cause the second search replacement to henceforth no longer occur.

  • I see that there are two replacement steps, just find it weird. They're are not true synonyms (g-c is the old version), and ColinD is not sure if they're to be merged.
    – maaartinus
    Apr 25, 2011 at 15:19
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    @maaartinus One replacement step autoreplaces search terms for popular tags to be tag searches (google-collections shouldn't actually qualify as far as I know, but it apparently does), while the other is autoreplaces child synonyms with their master synonyms. They usually don't happen sequentially because we generally merge synonyms after the synonym takes effect. If they are not true synonyms as you say, I would suggest posting a new Meta request to ask for the synonym to be broken.
    – Grace Note StaffMod
    Apr 25, 2011 at 15:21

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