Description:
As of waybar 0.9.9-2, clock widgets are broken when their format string includes %l (hour, space padded, 1..12) or %P (am/pm).

Minimal config file:

{"modules-left": ["clock"], "clock": {"format": "{:%Y-%m-%d %l:%M:%S %P}"}}

Steps to reproduce:

1. Install waybar 0.9.9-2 and run `waybar --config ‹config-file-path›`.
2. Note that the time is missing in the bar, and that the console shows “[error] : invalid format”.
3. Remove %l (changing to the supposedly-equivalent %_I doesn’t help), and change %P (am/pm) to %p (AM/PM) or remove it: it works.
4. To demonstrate that it is a regression, downgrade to waybar 0.9.9-1 and try again with the config file that failed in 0.9.9-2: it works.

I haven’t filed an issue on Waybar at this time since the regression is occurring in Arch package revisions.