The character ² is not a valid search character. On Electrical Engineering, one common term is I²C, sometimes (correctly) spelled as I²C (IIC or I-squared-C). A search for I²C does not throw an error, nor does it return anything with I²C. Instead it results in questions and answers including IC, an unrelated term. And the automatic URL recognition does not work when ² is in the URL.

For example https://electronics.stackexchange.com/questions/203076/i²c-bit-banging

Notice how it hyperlinks I²C bit banging to https://electronics.stackexchange.com/questions/203076/i, while dropping ²c-bit-banging?

Sometime between writing this bug report and 2022, the automatic URL recognition no longer tries to fix the URL. After editing the question, the broken renaming went away, so just the link shows. The rest still doesn't work properly.

Notably, ² is valid in a URL, so it will bring up the correct question if copied and pasted, or hyperlinked, but not in the search or URL parsing.

Can this be fixed by the code review team? This is a valid Unicode utf-8 character Superscript 2 hex 0x00B2

If anything, can a search for, and results for, ² be mapped to 2?

This is not a duplicate of that question, because this does not work, while that was fixed. So this is a new issue.

  • 2
    Related: Search and Unicode characters – Unicode characters should be valid search terms.
    – cde
    Nov 28, 2015 at 9:13
  • Re "dropping ²c-bit-banging": Is that still the case? What browser or mobile app (incl. version) was this tested on? Is it about rendering on the Stack Exchange pages? And/or what URL is redirected to in the browser? Mar 21, 2022 at 12:23
  • @This_is_NOT_a_forum As of the OP’s yesterday edit, it says that it is not the case any longer. You just removed the “Edit:” label that made that clear. Perhaps the whole discussion of URLs should be removed, now that it is no longer relevant. Mar 21, 2022 at 12:52
  • @emil no it is still broken, in a different way
    – cde
    Mar 21, 2022 at 15:07
  • Is it? As the post is written now, it says that the URL handling is fixed, only searching is broken. If this is not what you mean, please rewrite it clearly. Please remove all the distracting bits about what was broken before and how it changed. Just state clearly what is broken now. Mar 21, 2022 at 15:52


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