dotnet-suggest: Completion when launching global tool via "dotnet"

[ralish]

Tools that have a dotnet- prefix (e.g. dotnet-monitor) can be invoked via the main dotnet executable. I.e. you can launch a tool named dotnet-monitor by running dotnet-monitor or dotnet monitor (note the space). The latter simply results in dotnet launching the dotnet-monitor tool indirectly (so it's clearly less efficient), but from the user's perspective you get the same result.

The dotnet-suggest tool however only appears to successfully provide suggestions for tools that are directly invoked, even though such tools register both their potential entrypoints in .dotnet-suggest-registration.txt. I took a look at the code and the relevant part seems to be the FormatSuggestionArguments method in the SuggestionDispatcher class.

If the executable is dotnet it uses a different code path that strips the second token before passing it through to the target executable for suggestions. Some examples to help illustrate:

• dotnet monitor -> invokes dotnet [suggest:0] ""
• dotnet monitor config -> invokes dotnet [suggest:6] "config"
• dotnet monitor config show -> invokes dotnet [suggest:11] "config show"

I don't understand what this logic is trying to do. Is there some subtlety I'm missing here? Even if I manually send what I think should be the "correct" args to dotnet I still don't get back correct completions, e.g. dotnet [suggest:13] "monitor config", so it's unclear if this is meant to work at all, or ever did. But in that case, why do tools using System.CommandLine register their dotnet aliases?

I am very confused ...