Comment 5 for bug 1824688

I have ran a few tests on 16.04, 18.04, 18.10, and 19.04 (all X86_64):

16.04:

root@u1604:~# date +%-Y -d '- 2010 years'
9
root@u1604:~# date --version
date (GNU coreutils) 8.25
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.

18.04:

root@bionic:~# date +%-Y -d '- 2010 years'
9
root@bionic:~# date --version
date (GNU coreutils) 8.28
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.

18.10:

root@u1810:~# date +%-Y -d '- 2010 years'
9
root@u1810:~# date --version
date (GNU coreutils) 8.28
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.

19.04:

cerdea@piatam:/data/buildd/coreutils$ date +%-Y -d '- 2010 years'
date: invalid date ‘- 2010 years’
1 cerdea@piatam:/data/buildd/coreutils$ date --version
date (GNU coreutils) 8.30
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.

Interestingly, it is also failing on git head:

130 cerdea@piatam:/data/buildd/coreutils$ src/date +%-Y -d '- 2010 years'
src/date: invalid date ‘- 2010 years’
1 cerdea@piatam:/data/buildd/coreutils$ src/date --version
date (GNU coreutils) 8.31.12-6d78a
Copyright (C) 2019 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.