Calculation error in human_time_diff

[SGr33n]

Hi,
a few days ago I used human_time_diff() for the first time. It was in a wp-cron task manager, to check when the last run happened. Now the human_time_diff is rounded by php round, this means that if 2h and 1min ago it returns 2 hours ago, but if 2h, 30m and 1sec it returns 3 hours... and this is not true, because 3 hours haven't passed... and this also happens on 2 years and 1 hour (3 years?). So there is a patch to correct this, even if you want to correct it.

Thanks :)

[ocean90]

Introduced in [1976].

Related: #9272, #29849

[adamsilverstein]

@SGr33n good catch, thanks for opening the ticket.

I did some testing and can see that a difference of 2h, 30m and 1sec returns 3 hrs, however for 2 years and 1 hour the function returned 2 years. To get 3 years I had to use 2 years six months and a day.

After my testing, I'm not sure floor is actually better there than round, for example if 1 year 364 days have elapsed, floor will return 1 year which seems off. Furthermore, the existing behavior has been in core for 12 years, and changing it is likely to impact users who expect it to work as is. Finally, the human_time_diff filter applied on the returned value enables developers to adjust the default behavior for all uses.

In 38773.2.diff​ I added a few unit tests to verify the rounding behavior. All three assertions in test_rounding will fail before with round vs floor because they round up.

38773.3.diff​ is the unit tests only, adjusted to match the current core behavior, these will break if the patch is applied.

[SGr33n]

Hi @adamsilverstein, thanks :) you're right, I was wrong to write, It was 2 years 6 months and 1 day that returned 3 years.
So I will follow the thread to see how this will evolve.

[adamsilverstein]

38773.4.diff​
Add unit tests verifying the current rounding behavior of human_time_diff.

@SGr33n We aren't going to change this long-established behavior, by now the rounding is expected. if you want to change the core behavior to using floor, you can use the filter that runs at the end of the function, add something ​like this.

[adamsilverstein]

In 38773.5.diff​:
Add some additional test cases around the rounding margins.

[adamsilverstein]

In 41018:

Date/Time: Add unit tests for the human_time_diff function.

Verify that human_time_diff works as expected for minute, hour and day intervals. Test that rounding works as expected when the time difference is near the rounding margin.

Props SGr33n.
Fixes #38773.