The block time is parsed using PHP's strtotime() function (see SpecialBlock::parseExpiryInput()). strtotime() is known to be extremely lenient and prone to interpreting very stupid inputs as valid values. Other fun block durations to try include "100000 years" and "a potato" (see T51580).

In this case: strtotime( '3.14159265359 seconds' ); → 1620646599. This happens to be the Unix timestamp for Monday, May 10, 2021, 11:36:39 UTC. I'm not going to even attempt to figure out where this output comes from, but it sure does.

I think this is the expected behavior.

Oops, sorry Cyberpower for removing you as a subscriber ... I was trying
to figure out how to subscribe *myself* and was having great difficulty
due to my screen reader. I finally managed it with Firefox ...

Couldn't we check if something strange is being sent to the function to begin with. If we are setting seconds, we could validate it as an integer for example.

Now that I think about it, further examples might help. Both of these displayed correctly when I did them (2008/2009), but no longer do so.

Firstly, I blocked myself as a test for 2.71828 seconds, which now displays as 02:37 (UTC), 1 January 1970:
https://en.wikipedia.org/w/index.php?title=Special:Log&type=block&user=&page=Graham87&year=&month=-1&tagfilter=&subtype=

Then I blocked Giano for what was supposed to be 3.14159 seconds, but apparently appeared as 3 hours, here:
https://en.wikipedia.org/w/index.php?title=Special:Log&type=block&user=&page=User:Giano II&year=&month=-1&tagfilter=&subtype=

That block now displays as 03:16, 1 January 1970 (UTC).

In T133438#2232333, @Cyberpower678 wrote:

Couldn't we check if something strange is being sent to the function to begin with. If we are setting seconds, we could validate it as an integer for example.

The function is supposed to check for strange values itself. It does reject some inputs, at least. Trying to second-guess it and writing our own parser doesn't seem very worthwhile to me. It seems that the only situation where this causes problems is joke blocks. ;)

In T133438#2235608, @matmarex wrote:

In T133438#2232333, @Cyberpower678 wrote:

Couldn't we check if something strange is being sent to the function to begin with. If we are setting seconds, we could validate it as an integer for example.

The function is supposed to check for strange values itself. It does reject some inputs, at least. Trying to second-guess it and writing our own parser doesn't seem very worthwhile to me. It seems that the only situation where this causes problems is joke blocks. ;)

I would say for the case of seconds, we need to round that number to an integer. Alternatively we could leave it, as an Easter egg for April Fools.

Ha, I actually figured out what '3.14159265359 seconds' means. It means 3:14 AM today, plus 159265359 seconds. Nothing we could round here.