fix(amazonq): inline suggestion scrolling now uses built-in VSC commands.

[Hweinstock]

Problem

The current implementation overwrites the editor.action.inlineSuggest.showPrevious and editor.action.inlineSuggest.showNext commands to swap out the inlineProvider. These custom overwrites cause a few issues:

• forces us to maintain a ton of state [leads to bugs, some of which were observed in bug bash].
• causes the suggestions to "refresh" when going through them since we are re-instantiating the provider on "scrolls".
• doesn't natively support "accept word"/"accept line".

Solution

• Remove the overwrite, remove reliance of session state.
• Simplify implementation to use native VSC commands.

Fixed Bugs

• Scrolling through suggestions now works and doesn't "refresh".
• Accept Word/Accept Line now work properly.
• Significantly faster to scroll through suggestions.
• Inline Reference Codelense no longer flashes when scrolling through suggestions.

Tests and Verification:

Testing this change it feels significantly 'smoother'.

suggestionScrollingFIx.mov

Future Work

• with some more aggressive refactoring, and once telemetry is mostly in Flare, we can completely delete the sessionManager.
• revisit reference codelense, and see if its the right choice. Maybe a message instead?

---

• Treat all work as PUBLIC. Private feature/x branches will not be squash-merged at release time.
• Your code changes must meet the guidelines in CONTRIBUTING.md.
• License: I confirm that my contribution is made under the terms of the Apache 2.0 license.

[Hweinstock]

lint-duplicate-code failure is unrelated:

[
  {
    first: 'https://github.com/aws/aws-toolkit-vscode/blob/ab045d280548db0929d2958ad96a39ceacbcaea1/packages/core/src/codewhisperer/util/runtimeLanguageContext.ts#L262-L276',
    second: 'https://github.com/aws/aws-toolkit-vscode/blob/ab045d280548db0929d2958ad96a39ceacbcaea1/packages/core/src/codewhisperer/util/runtimeLanguageContext.ts#L141-L155',
    numberOfLines: [15](https://github.com/aws/aws-toolkit-vscode/actions/runs/15057354954/job/42325918841?pr=7323#step:10:16)
  }
]

[jpinkney-aws]

cc @zixlin7 was this stuff added to support inline completions that come after the initial request? or is it no longer needed? As far as I can see from the demo we still have pagination

[Hweinstock]

My understanding of the old implementation is that we fetch all the suggestions, add them to the session, and then request them from the session one at a time (by triggering the provideInlineCompletion via overwriting the scroll commands). This is where the state tracking comes in to manage what the "active" suggestion is. We also add 'placeholder' items so that VSC knows we can scroll.

Since we're fetching all the suggestions anyway, we can return those directly and avoid 'placeholder' items, and additional triggers of provideInlineCompletion.

However, I don't have all the context on the original reason for this decision.

When testing this, I also noticed a slight bug on current prod where it always shows were on suggestion 1, even when we scroll.

[Hweinstock]

Checked with Zoe and sounds like this is a hack to handle the codelenses for references and imports.

• references are confirmed working in fix(amazonq): code reference codelense works #7331.
• import codelense is unknown. Note: There weren't any reported issue in first three bug bashes, so either this is not a common case, or already works. However, still worth following up to confirm this.