Audit which inspector service extensions are used in DevTools

[kenzieschmoll]

Widget inspector service extensions are defined here: https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/widgets/service_extensions.dart#L106

and registered here:
https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/widgets/widget_inspector.dart#L986

We should audit which extensions are actually used in DevTools, and remove the rest. This will prevent us from having to do unnecessary work to make unused extensions work for multiwindow support.

[kenzieschmoll]

disposeAllGroups is currently unused in DevTools.
Recommendation: remove, unless this will actually be needed for multiwindow support (if there are many groups or something like that).

disposeId is currently unused in DevTools.
Recommendation: remove.

getParentChain is currently unused in DevTools.
Recommendation: remove. This is unused in DevTools. It has been sitting in commented out code for a long time.

trackRepaintWidgets is currently unused in DevTools.
Recommendation: do not remove, as this may be used in the Performance page to support showing repaints for a frame.

screenshot is currently unused in DevTools.
Recommendation: do not remove. This is something we will likely want to use in the future.

setPubRootDirectories is currently unused in DevTools.
Recommendation: do not remove. We can remove if the IDEs move away from this API, but this implementation uses the logic for the new add and remove APIs, so it shouldn't be extra work to leave this for now.

@jacob314 can you please comment if you disagree with any of the recommendations here.
@DanTup and @helin24 can you comment if any of the extensions I have tagged with a remove recommendation are used by the IDEs? Thanks.

[kenzieschmoll]

FYI @goderbauer

[goderbauer]

For completeness: Does DevTools make use of any of the other more general service extensions?

• https://github.com/flutter/flutter/blob/ac76dabe6744f4636a86da366ed1a2ce6973f689/packages/flutter/lib/src/widgets/service_extensions.dart#L13
• https://github.com/flutter/flutter/blob/ac76dabe6744f4636a86da366ed1a2ce6973f689/packages/flutter/lib/src/rendering/service_extensions.dart#L13
• https://github.com/flutter/flutter/blob/ac76dabe6744f4636a86da366ed1a2ce6973f689/packages/flutter/lib/src/scheduler/service_extensions.dart#L13
• https://github.com/flutter/flutter/blob/ac76dabe6744f4636a86da366ed1a2ce6973f689/packages/flutter/lib/src/services/service_extensions.dart#L13
• https://github.com/flutter/flutter/blob/ac76dabe6744f4636a86da366ed1a2ce6973f689/packages/flutter/lib/src/foundation/service_extensions.dart#L13

[DanTup]

@kenzieschmoll

As far as I know, only setPubRootDirectories is used by VS Code from the inline list above. ext.flutter.inspector.show is also used.

The current/legacy Flutter DAP also uses ext.flutter.inspector.getSelectedSummaryWidget and ext.flutter.inspector.disposeGroup. The new SDK DAP does not (it uses the new ToolEvent stream), so in time these will become unused by VS Code.

@goderbauer of your list(s), VS Code uses:

• ext.flutter.platformOverride
• ext.flutter.debugAllowBanner
• ext.flutter.debugPaint
• ext.flutter.debugPaintBaselinesEnabled
• ext.flutter.brightnessOverride
• ext.flutter.repaintRainbow
• ext.flutter.showPerformanceOverlay
• ext.flutter.timeDilation

[goderbauer]

Thanks!

Side question: What is "Flutter DAP"?

so in time these will become unused by VS Code.

What will mark the end here? Do we just have to wait a certain amount of time? Or wait until a certain version is released?

[DanTup]

Side question: What is "Flutter DAP"?

DAP is the Debug Adapter Protocl. It's a protocol for an editor (like VS Code) to talk to a debugger (like the Dart VM/VM Service). If lots of editors and lots of languages adopt this, there is less per-editor-per-language work that needs to be done. We have wrappers over the VM Service that translate into this protocol (they're more structly "DAs" - Debug Adapters, but DAPs is shorter to say 😄).

The original implementation of the DAP was inside Dart-Code (written in TypeScript), and was intended only for use by VS Code (so it had a lot of customisations). The new DAP implementations like in the Dart/Flutter SDKs and are written in Dart (and usable by many other DAP-compliant editors):

• https://github.com/dart-lang/sdk/blob/main/pkg/dds/tool/dap/README.md
• https://github.com/flutter/flutter/blob/master/packages/flutter_tools/lib/src/debug_adapters/README.md

What will mark the end here? Do we just have to wait a certain amount of time? Or wait until a certain version is released?

After Dart 3 ships, I hope to begin migrating VS Code users over to the new ones. How quickly this occurs depends on whether we find any significant bugs in them. We found some blocking bugs with the last stable release so the migration was postponed. Those issues are fixed now and I plan to begin re-enabling the new SDK DAPs for Flutter pre-release versions (with all the fixes) once the next DWDS goes out (to get dart-lang/webdev#2011).

[goderbauer]

To make it easier to see what is and isn't used I translated the information on this bug into a spreadsheet: https://docs.google.com/spreadsheets/d/1i1RW8Q0pNxBc6vWva9y5Wp_EPNoE6uyJqrIUwGGb_mM/edit#gid=0

If people could fill in some of the missing information, I'd appreciate it.

I also added flutter_tools as a user of these extension.

[helin24]

@kenzieschmoll among the ones you tagged as 'remove', getParentChain is used by IntelliJ.

@goderbauer I noted in the IntelliJ column which service extensions NOT used by DevTools are still used by IntelliJ, but I didn't look for all of the service extensions. If there are other that may be removed based on our usage let me know and I'll check.

[kenzieschmoll]

Finished updating spreadsheet for DevTools extensions @goderbauer

[kenzieschmoll]

Closing as this audit is complete from the DevTools perspective.