commit 9f42ef774ead524aee0650bba35a531b88bb29ff
author Jens Johansen <jensj@google.com> Tue Apr 01 00:56:39 2025 -0700
committer Commit Queue <dart-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Apr 01 00:56:39 2025 -0700
tree c2e64419068690d377d5fd1b176e5226f4396f39
parent f6fcd37cb88a974a24ef48510f2cbf00b8560279

[analyzer] Add "interactive" option to "getResolvedUnit"; "setSubscriptions" are not; non-interactive ones have less priority

The legacy_many_files_in_flutter_set_subscriptions benchmark shows how
"flutter.setSubscriptions" calls can make the analyzer slower to
respond.

What happens is this:

* The user opens a new file in the IDE.
* The IDE sends the `flutter.setSubscriptions` request which equates to
  a call to `getResolvedUnit` for each file in the request. If this is,
  say, 300 files it's 300 calls to `getResolvedUnit`.
* The IDE sends a `edit.getAssists` request for the newly opened file.
  This request starts processing, reaches `getResolvedLibrary(file)`
  which calls `getUnitElement` ultimately adding the path to
  `_unitElementRequestedFiles` which in `performWork` is done _after_
  `_requestedFiles`, meaning it has to do all the flutter requested
  files first.
* The user might then request completion for instance, but because the
  analyzer only processes one request at a time it has to wait for the
  `edit.getAssists` request to finish first, which had to wait for the
  files from the `flutter.setSubscriptions` request to process.

All in all it's a lot of waiting for the user.

This CL adds a `interactive` option to the `getResolvedUnit` call. It
defaults to true in which case files are still added to
`_requestedFiles` and processed the same. If it's false it will instead
be added to a newly introduced list instead and processed at a lower
priority. Subscription requests are changed to pass `false` to
`interactive`, avoiding the scenario above.

Comparing before this CL with this CL on the
"legacy_many_files_in_flutter_set_subscriptions" benchmark with 100
files / CodeType.ImportChain these are the statistics on the changes
based on 5 runs each:

```
Completion after open of new file: -81.6652% +/- 7.7564% (-3.70 +/- 0.35) (4.53 -> 0.83)
getAssists call: -96.6315% +/- 0.9307% (-3.61 +/- 0.03) (3.74 -> 0.13)
peak virtual memory size: -5.6786% +/- 3.2964% (-139.00 +/- 80.69) (2447.80 -> 2308.80)
total program size (virtual): -4.6387% +/- 3.8146% (-110.80 +/- 91.11) (2388.60 -> 2277.80)
```

Even when https://github.com/flutter/flutter-intellij/issues/7980 is
hopefully fixed I think it is a fair change to de-prioritize a
non-interactive request.

Change-Id: Icba2faebf12f9913cf24db7cb90fdc6f4c74164e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/418020
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Jens Johansen <jensj@google.com>