illumos gate

While trying to test something, I was running through the ksh93 test suite and noticed the following failure from it:

test builtins begins at 2022-01-15+19:28:11
        builtins.sh[320]: printf "%T" now
test builtins failed at 2022-01-15+19:28:19 with exit code 1 [ 161 tests 1 error ]
test builtins(C.UTF-8) begins at 2022-01-15+19:28:19
        builtins.sh[320]: printf "%T" now
test builtins(C.UTF-8) failed at 2022-01-15+19:28:28 with exit code 1 [ 161 tests 1 error ]
test builtins(shcomp) begins at 2022-01-15+19:28:28
        shcomp-builtins.ksh[320]: printf "%T" now
test builtins(shcomp) failed at 2022-01-15+19:28:36 with exit code 1 [ 161 tests 1 error ]

If we look at the test, it has the following line in and of itself:

318 [[ $(printf '%T\n' now) == "$(date)" ]] ||
319 [[ $(printf '%T\n' now) == "$(date)" ]] ||
320 err_exit 'printf "%T" now'

However, if we look at the output of these two things, we'll see that they can never equal, no matter how fast we are:

u@h:w$ printf '%T\n' now; date                         
Sat Jan 15 19:40:36 GMT 2022
Sat Jan 15 19:40:36 UTC 2022

While in the there's both LANG=C.UTF-8 and TZ=UTC, it appears that ksh93 printf builtin prefers to think of it as GMT instead of UTC, leading to this always failing, even if you get within the same second.