Flutter autocomplete suggestions not working

[BojanDolic]

My autocomplete suggestions just stopped working.
As an example, none of the widgets show inside suggestions window when I start typing, here is the screenshot when I want to add BoxDecoration:

First image
Second image

Steps to Reproduce

I'm not exactly sure how this happened, but the issue started when I ran android emulator inside tool window ( I ran it as a separate window before.)

I created this project few days ago and everything was working fine until now.

Version info

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 2.10.1, on Microsoft Windows [Version 10.0.19043.1526], locale sr-Latn-BA)
[!] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    X cmdline-tools component is missing
      Run `path/to/sdkmanager --install "cmdline-tools;latest"`
      See https://developer.android.com/studio/command-line for more details.
    X Android license status unknown.
      Run `flutter doctor --android-licenses` to accept the SDK licenses.
      See https://flutter.dev/docs/get-started/install/windows#android-setup for more details.
[√] Chrome - develop for the web
[X] Visual Studio - develop for Windows
    X Visual Studio not installed; this is necessary for Windows development.
      Download at https://visualstudio.microsoft.com/downloads/.
      Please install the "Desktop development with C++" workload, including all of its default components
[√] Android Studio (version 2020.3)
[√] Android Studio (version 2021.1)
[√] IntelliJ IDEA Community Edition (version 2021.1)
[√] Connected device (4 available)
[√] HTTP Host Availability

! Doctor found issues in 2 categories.

Edit:
I tried to fix it with invalidate caches and restart, flutter clean, without emulator running, running emulator outside tool window again. None of those things fixed the problem.

[stevemessick]

BoxDecoration is part of Material Design. Do you have uses-material-design: true in your pubspec.yaml?

[BojanDolic]

BoxDecoration is part of Material Design. Do you have uses-material-design: true in your pubspec.yaml?

Yes I do. Everything was working correctly until now. Autocomplete for widgets worked fine until now.
I tried restarting my PC also which didn't help.

I also tried autocomplete in another project and it worked fine. I created empty project and autocomplete also worked so it seems that the issue is tied to this project but what is bothering me is that everything was ok until I launched emulator.

[stevemessick]

I would not expect the emulator to affect completion. To be honest, this is a puzzle. I don't know what project-specific thing could cause this. Your quickest remedy may be to re-create your project. If you don't want to do that you could try Flutter Pub Get and Flutter Pub Upgrade from the Tools > Flutter menu.

Have you ever opened the Android module as its own project in Android Studio (Tools > Flutter > Open Android module in Android Studio)? That could possibly cause changes (rarely).

[BojanDolic]

I would not expect the emulator to affect completion. To be honest, this is a puzzle. I don't know what project-specific thing could cause this. Your quickest remedy may be to re-create your project. If you don't want to do that you could try Flutter Pub Get and Flutter Pub Upgrade from the Tools > Flutter menu.

Luckily project is not big so I recreated it. I tried Flutter Pub Get and Flutter Pub Upgrade with no success.

Have you ever opened the Android module as its own project in Android Studio (Tools > Flutter > Open Android module in Android Studio)? That could possibly cause changes (rarely).

I did not. When I go to Tools > Flutter there is no Open Android module in Android option shown.

[stevemessick]

Sorry, but the menu item name changes depending on what is selected in the Project view. In your screen shot, it is named Open for Editing in Android Studio. Have you used that?

Does completion work as expected in the new project?

Since I'm guessing the answers to these two questions are "no" and "yes", I'm going to see if I can get some help trying to understand what went wrong in the original project.
@alexander-doroshko @bwilkerson can you think of anything that might explain the original problem?

[bwilkerson]

I can think of a couple of possibilities, but they all seem very unlikely.

Code completion depends on analysis, and analysis depends on having a valid and up-to-date package_config.json file. If something caused the file to be corrupted that could explain the problem.

Analysis also depends on being able to read the source for those packages from the .pub-cache directory. If one of the packages in that directory was corrupted that could potentially cause problems.

Or if some of the files needed for analysis are on a file system that became inaccessible, that could potentially cause problems.

... I ran android emulator inside tool window ( I ran it as a separate window before.)

@stevemessick Is there something different about how the emulator runs when running in a tool window that would explain this?

@BojanDolic If you manually type BoxDecoration does the analyzer find the class (not produce a diagnostic saying that it's undefined)? Can you navigate to it? If the answer to these is "yes" than analysis appears to be working correctly, so my previous guesses are disproven.

[BojanDolic]

@bwilkerson Yes, I can even click to open its source code. Here is the video, hope it will help:

2022-02-25-19-06-32.mp4

[stevemessick]

@BojanDolic When using the project you re-created and running the emulator in the embedded window, does completion work as expected?