Someone filed an issue today that I don't think is from Drupal Core, but it very well could be.
See
#1145964: search module running into comma as decimal place problem →
, comment #1 for an explanation of what is happening -- basically, the person is seeing an SQL error due to having a query where 8,1918095044299 is supposed to be treated as a number (but SQL can't figure it out, because it has a comma in it instead of a period for the decimal point).
This issue (even though it is probably not a core issue but a problem with a contrib module) made me question whether we actually know that the Drupal Core test suite would pass on, for instance, a machine where PHP's locale tells it to print out a comma for a decimal point.
So I'm filing this issue to bring up the discussion... I put it in the locale.module component because that seems to be the most related, but it's really about (I think) the PHP locale, not the Drupal locale.
Is there testing in core now that covers this?
Closed: outdated
9.5
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Definitely a mistake from #15, probably when I kept too many drupal issues open.
But since there hasn't been a follow up to #16 going to reclose for inactivity.
If still a valid task though please reopen updating the issue summary.
Thanks all!