Detect new available names in bus

[Thomas Kluyver]

On Thu, 17 Feb 2022, at 04:52, Lawrence D'Oliveiro wrote:
> Is there any reason why bus peers need to be aware of the difference
> between an “activatable” service and one which is already running?

In practice, a method call on an activatable name is likely to be slower and less reliable (because the service may fail to start) than calling a service which is already running. So I'd like to have some way to distinguish these cases.

We had issues with the Python keyring library that would sometimes hang for 10s of seconds while D-Bus tried to launch a keyring/wallet service which was getting stuck (I think maybe prompting for a password in a way that wasn't visible). We didn't end up checking 'is this already running' in that case, but it illustrates why you might care about the distinction.

Thomas