Remove unnecessary options

[tmat]

ForceRoslynLSPCompletionExperiment is no longer necessary since LspCompletionFeatureFlag feature flag can be turned on/off directly as a global option.
UsePartialSemanticForCompletion is a test-hook flag that can be set directly on CompletionServiceWithProviders.

[tmat]

@allisonchou

[CyrusNajmabadi]

Approving with the TestAccessor change.

[allisonchou]

Thanks Tomas! lgtm.

[sharwell]

LspOptions.LspCompletionFeatureFlag only has a feature flag storage location. Feature flags cannot be set on machines without telemetry enabled (not even through manual local override for testing), so we either need to retain the ForceRoslynLSPCompletionExperiment option or add a RoamingProfileStorageLocation to LspCompletionFeatureFlag

[tmat]

LspOptions.LspCompletionFeatureFlag only has a feature flag storage location. Feature flags cannot be set on machines without telemetry enabled (not even through manual local override for testing), so we either need to retain the ForceRoslynLSPCompletionExperiment option or add a RoamingProfileStorageLocation to LspCompletionFeatureFlag

Is this to allow manually changing it in the registry? I don't understand the scenario.

[sharwell]

Is this to allow manually changing it in the registry?

Yes, otherwise there is no way to test the flag.

[tmat]

Is this to allow manually changing it in the registry?

Yes, otherwise there is no way to test the flag.

Testing where? Integration tests on CI? In unit tests the flag is tested, the registry storage is not needed. Integration Tests can also use IGlobalOptionsService to set the flag as needed.

[sharwell]

Testing where?

Locally. It's impossible to set a feature flag for local testing. All feature flags are backed by secondary option with registry storage so local developers can set the value for smoke testing and/or debugging.

[genlu]

UsePartialSemanticForCompletion part LGTM

[tmat]

@sharwell This feature flag can be set locally in UI here:

[sharwell]

@tmat Awesome, verified locally that IVsFeatureFlags (unlike IVsExperimentationService) can be used locally when telemetry is disabled.

[tmat]

Thanks for the extra validation!

[sharwell]

Note this means there are a bunch of other options using the dual pattern that can likely be consolidated.

[tmat]

@sharwell Yeah, that's likely. Will add it to the list of things to clean up :)

[tmat]

Not all our feature flags are shown in the above UI. Maybe they should be. #55974

[sharwell]

I don't think we need to show all feature flags in the UI. For items we don't expect users to change, it's sufficient to allow them to be set via vsregedit.