Comment 11 for bug 1839290

Thank you, Dan.
The PPA build indeed fixes the test case in #8, for Xenial at the very least. Sending SIGABRT to foo.service's process now causes services to restart, just as intended. Here are the logs from the very same Xenial machine, as in #8:

$ sudo apt install systemd=229-4ubuntu21.28~next20200212b2
<...>
$ sudo systemctl daemon-reexec
$ sudo systemctl status foo bar
● foo.service
   Loaded: loaded (/etc/systemd/system/foo.service; static; vendor preset: enabled)
   Active: active (running) since Thu 2020-02-13 11:04:06 MSK; 5min ago
 Main PID: 4753 (sleep)
   CGroup: /system.slice/foo.service
           └─4753 /bin/sleep infinity

Feb 13 11:04:06 pono-mac systemd[1]: Started foo.service.

● bar.service
   Loaded: loaded (/etc/systemd/system/bar.service; static; vendor preset: enabled)
   Active: active (running) since Thu 2020-02-13 11:04:06 MSK; 5min ago
 Main PID: 4759 (sleep)
   CGroup: /system.slice/bar.service
           └─4759 /bin/sleep infinity

Feb 13 11:04:06 pono-mac systemd[1]: Started bar.service.

$ sudo kill -6 4753
$ sudo systemctl status foo bar
● foo.service
   Loaded: loaded (/etc/systemd/system/foo.service; static; vendor preset: enabled)
   Active: active (running) since Thu 2020-02-13 11:12:05 MSK; 2s ago
 Main PID: 11122 (sleep)
    Tasks: 1
   Memory: 200.0K
      CPU: 1ms
   CGroup: /system.slice/foo.service
           └─11122 /bin/sleep infinity

Feb 13 11:12:05 pono-mac systemd[1]: Stopped foo.service.
Feb 13 11:12:05 pono-mac systemd[1]: Started foo.service.

● bar.service
   Loaded: loaded (/etc/systemd/system/bar.service; static; vendor preset: enabled)
   Active: active (running) since Thu 2020-02-13 11:12:05 MSK; 2s ago
 Main PID: 11123 (sleep)
    Tasks: 1
   Memory: 224.0K
      CPU: 1ms
   CGroup: /system.slice/bar.service
           └─11123 /bin/sleep infinity

Feb 13 11:12:05 pono-mac systemd[1]: Started bar.service.

I'll test it with Bionic in a few hours.