Provide an option to disable usage of Get-Help for IntelliSense results

[verysmallposhscript]

There's a long delay in intellisense results on default cmdlets, as shown in the gif. It's taking upwards of 10 seconds after typing in a partial cmdlet name before the intellisense results pop up.

[daviwil]

Hey @verysmallposhscript, thanks for the report. I have a feeling that the delay is coming from our use of Get-Help to gather the details for the cmdlet. It's likely that I'll need to add an option to disable this help querying when the user finds it slowing down their IntelliSense. I'll add this in an upcoming release.

Regarding the tab-completion issue you mentioned on Reddit, I'll talk to the VS Code team to see if they can add a way to cycle through IntelliSense results so that we can have an experience that's more like what PowerShell developers are used to.

[ChrisLynchHPE]

I hope progress can be made on this issue. Intellisense either becomes broken (with 'Loading...' and eventually just goes away), or extremely slow to generate the list (even on a blank line). It makes development of PowerShell libraries really difficult.

I should also specify that this happens for me when I'm developing within my main module (which currently has >70K lines of code). When I'm in a new PowerShell file, no issues.

VSCode: 1.4.0
PowerShell Extension: 0.7.0
Windows 10 $PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.1.14905.1000
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.14905.1000
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

[daviwil]

Hey Chris, I'm going to prioritize this issue now that the cross-platform work is done. It's annoying me too at times.

@verysmallposhscript: How's the delay going for you in the latest releases of VS Code (1.4.0) and the PowerShell extension (0.7.10?

[ChrisLynchHPE]

Thanks! I was using Visual Studio 2013, but VSCode is so much lighter overall. I love the progress both projects have made. Hopefully this performance bug can be squashed!

[rkeithhill]

@daviwil It would be nice if VSCode would allow us to return the completion list in phases. First we give VSCode the raw-ish completion data sans help. Then as someone moves up and dow the list, VSCode queries to see if there is more "info" for that completion item. Kind of like how they handle scopes today with the expensive property. Perhaps it is only when expensive is true that VSCode asks for more info on a particular completion.

[daviwil]

Technically they do allow that right now, there's an initial "completions" request that gets the list and then the "resolve" request that asks for further details about the currently selected completion. It could be that using Get-Help to get cmdlet details could be causing a slowdown.

[rkeithhill]

@daviwil Do we spin up the Get-Help task on another thread right after the initial request? And do (should) we cache that information? Ideally, the resolve request would come in and we'd either have the cache entry populated or not and return quickly. Over time, the Get-Help bg task(s) would finish and fill in the cached data? Just brainstorming a bit here.

[daviwil]

Crap, GitHub totally wiped out the text I had written here :( Anyway, we invoke Get-Help right after the user highlights one of the completion results they get back (the resolve step). I've filed an issue on the PSES repo to track the need for a cache:

PowerShell/PowerShellEditorServices#280