datediff duration format spec %0 (and %SPC) for padding to any desired fixed width

[UNIVAC-Colonel-Panic]

UTC date duration is my particular use case - how to zero (or space) pad to fixed width to line up in a column?

Sample code

#!/bin/bash

oldest=1529218800 # approx 2018-06-17
 older=1606723200 # approx 2020-11-30
 newer=1608796800 # approx 2020-12-24
newest=1609304992 # approx 2020-12-29

datediff -i "%s" -f "%000dd:%0Hh:%0Mm:%0Ss" $oldest $older

datediff -i "%s" -f "%000dd:%0Hh:%0Mm:%0Ss" $older  $newer

datediff -i "%s" -f "%000dd:%0Hh:%0Mm:%0Ss" $newer $newest

Actual output from above:

897d:01h:00m:00s
24d:00h:00m:00s
05d:21h:09m:52s

Goal is to pad the number of days to be a fixed width of three digits:

897d:01h:00m:00s
024d:00h:00m:00s
005d:21h:09m:52s

The man datediff page says %0 is the modifier to pad refined values with zeroes but it seems to only pad out to two character positions vs. one character for each 0 I put in the format spec. If this is working as designed, can this be made as a feature request? It doesn't have to be implemented like in my example -- %000 -- but using whatever method is practical.