The Flutter SDK is not available.

[CryptUser]

With a new installation of Flutter, following the reflectable tutorial on https://github.com/dart-lang/reflectable I get to the point were the command "pub run build_runner build lib" results in the error: "The Flutter SDK is not available".

For the reproduction as follows I removed my flutter path, and installed it fresh (but still have the plugins for IntelliJ IDEA and Android Studio). Note: Installation is working fine for other purposes as compiling sample app, etc.

How to reproduce:

1. Install Flutter as usual for Mac:
   a) cd ~/development
   b) git clone -b beta https://github.com/flutter/flutter.git
   c) export PATH=/Users/myname/development/flutter/bin:$PATH
   d) flutter doctor

[✓] Flutter (Channel beta, v0.5.1, on Mac OS X 10.13.5 17F77, locale en-SE)
[!] Android toolchain - develop for Android devices (Android SDK 27.0.3)
! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses
[!] iOS toolchain - develop for iOS devices (Xcode 9.2)
✗ libimobiledevice and ideviceinstaller are not installed. To install, run:
brew install --HEAD libimobiledevice
brew install ideviceinstaller
✗ ios-deploy not installed. To install:
brew install ios-deploy
✗ CocoaPods not installed.
CocoaPods is used to retrieve the iOS platform side's plugin code that responds to your plugin usage on the Dart side.
Without resolving iOS dependencies with CocoaPods, plugins will not work on iOS.
For more info, see https://flutter.io/platform-plugins
To install:
brew install cocoapods
pod setup
[✓] Android Studio (version 3.0)
[✓] IntelliJ IDEA Community Edition (version 2017.3)
[!] VS Code (version 1.24.1)
[✓] Connected devices (2 available)

2. New Flutter project in IntelliJ Idea
   a) Choose SDK path: /Users/myname/development/flutter
   b) Choose project location: ~/gitroot/PlayGround/reflectable_test

3. Follow reflectable tutorial (from https://github.com/dart-lang/reflectable):
   a) Replace lib/main.dart with the main.dart from https://github.com/dart-lang/reflectable
   b) Add "reflectable: any" to pubspec.yaml under dependencies
   c) In main.dart, click on the now appearing "get dependencies"
   (import 'main.reflectable.dart'; still shows an error)
   d) On the command line:
   cd /Users/myname/gitroot/PlayGround/reflectable_test/
   pub run build_runner build lib

Result: shows "The Flutter SDK is not available."

[zoechi]

In a Flutter project you need

flutter packages pub run build_runner build lib

[CryptUser]

Thank you! This, and adding "build_runner: any" to the dependencies made the program run. Strangely, however, it did not create the file "main.reflectable.dart" which I expected. Did I miss something here?

[zoechi]

It's better to add it to dev_dependencies: because it's not imported from code in lib/.
I haven't used reglectable myself yet. Perhaps better to ask there ot on StackOverflow.

[CryptUser]

Thanks for your comment. I did as you said. Additionally, I had found somewhere else that one shouldn't use lib as the entry point, so I moved main.dart to a parallel directory entry_point and ran "flutter packages pub run build_runner build entry_point". It didn't complain, but resulted in "Succeeded ... with 0 outputs". Deleting the .dart_tool/ directory didn't help. I'll put the question on StackOverflow as you suggested.

[zoechi]

Where did you read that about the entry_point?
Can you please also post a link to the SO question?

[zoechi]

See also google/reflectable.dart#117

[CryptUser]

I read about the entry points in another issue, but unfortunately do not seem to find it again. Anyway, it said that lib is only for libraries, and one should use another directory as entry point (the reflectable tutorial uses "web", by the way). I'll put a link to the SO question, once it's published.

[zoechi]

Command line apps use bin/, browser apps use web/, and Flutter apps use lib/.
Entrypoint files in lib/ cause some problems because they weren't anticipated there, but so far there were only troubles if lib/main.dart contained relative imports or was imported by another file.
Flutter expects the entry-point file in lib, so there is no point in moving it somewhere else.

[CryptUser]

Thanks for the explanation. Meanwhile I got the SO question published: https://stackoverflow.com/questions/51169706/flutter-reflection-with-reflectable-working-example-needed

[eernstg]

Doing the things that you describe, @CryptUser, I do get the following:

tmprepos/reflectable_flutter/flutter19049/flutter_app$ flutter packages pub run build_runner build test/reflectable_test.dart
[INFO] Generating build script...
[INFO] Generating build script completed, took 430ms

[INFO] Initializing inputs
[INFO] Building new asset graph...
[INFO] Building new asset graph completed, took 520ms

[INFO] Checking for unexpected pre-existing outputs....
[INFO] Checking for unexpected pre-existing outputs. completed, took 2ms

[INFO] Running build...
[INFO] 1.0s elapsed, 0/2 actions completed.
[INFO] 2.1s elapsed, 0/2 actions completed.
[SEVERE] reflectable on test/widget_test.dart:
Unable to resolve asset ID for "dart:ui"
[INFO] reflectable on test/widget_test.dart:Ignoring entry point flutter_app|test/widget_test.dart that does not include the library 'package:reflectable/reflectable.dart'
[INFO] Running build completed, took 12.8s

[INFO] Caching finalized dependency graph...
[INFO] Caching finalized dependency graph completed, took 35ms

[INFO] Succeeded after 12.9s with 1 outputs

Not sure where our experiments diverge, but it "should work" as far as I can see... ;-)

[zoechi]

@eernstg could you make the example project available on GitHub somewhere?

[eernstg]

Sure. I'd expect android and ios to be omitted because they are created/downloaded. The rest is here: https://github.com/eernstg/reflectable-flutter.

[CryptUser]

Thanks for the example project, this works for me as well :-)
It's strange that when you did the same you got a different result, but with your example project at hand I may be able to find out where the difference was. Thanks again!

[eernstg]

Thank you! I've fixed it up a bit more such that it actually uses Flutter, and a build.yaml.

[eernstg]

It's strange that when you did the same you got a different result

No, it's always like that. ;)

[CryptUser]

Trying a bit further, I realised, that when moving main.dart to the test folder, and running flutter packages pub run build_runner build test, the file main.reflectable.dart IS created. However, when I move main.dart to the lib folder, and run flutter packages pub run build_runner build lib, this file IS NOT created. This behaviour appears to be repeatable. Note that I used the project as described at the top for this, without a build.yaml file. Any ideas why this is? Is this special for a file name main.dart?

[eernstg]

moving main.dart to the test folder .. main.reflectable.dart IS created

@CryptUser, I have considered this behavior to be a built-in property of the build package, in the sense that it does not handle code generation for libraries under lib (reflectable does take such libraries into account, and also libraries from other packages, but it doesn't output any files under lib).

However, you mentioned the following here and here:

I had found somewhere else that one shouldn't use lib as the entry point

.. but unfortunately do not seem to find it again.

I had the same experience, I can't find it today. I've asked the main creator of the build package about this issue, will return later when I know more.

[CryptUser]

I should say that I also tested to move main.dart to other directories (entry_point, other) and performed the respective flutter packages pub run build_runner build entry_point or flutter packages pub run build_runner build other, respectively. The file main.reflectable.dart is only created when I use the directory test, not in any of the other directories. In other words, it's not lib which appears to be special, but test.

[zoechi]

I gues build.yaml should then also include - lib/**.dart in generate_for:?

[CryptUser]

I didn't use build.yaml at all, since the tutorial at https://github.com/dart-lang/reflectable does not mention it's use. I'll try if I get it working with this file.

[eernstg]

.. the tutorial at https://github.com/dart-lang/reflectable does not mention [build.yaml]

Right, I discovered that as well. I'll add something about that, but it's all 'package build' related so you should be able to learn whatever there is to learn about build.yaml over there.

[eernstg]

[should] include - lib/**.dart in generate_for:?

That's exactly what I've asked about when I got in touch with the main creator of the build package (@jakemac53), but that clause came from him, so I assumed that it was needed.

[CryptUser]

Adding the build.yaml from https://github.com/eernstg/reflectable-flutter to my project, the file main.reflectable.dart is still not created, when I use folders "other" or "entry_point" (for both the build.yaml and the flutter command, of course). Probably it's better to start from the working repo, and see what it takes to break it ;-)

[eernstg]

Would be great, and do tell us about it!

[CryptUser]

Shouldn't the following work?

• Take the repo https://github.com/eernstg/reflectable-flutter and add a folder other parallel to lib.
• Take the main.dart from https://github.com/dart-lang/reflectable (called web/main.dart there) and put it in the other folder.
• In the build.yaml, replace "test" with "other" in the generate_for path.
• On the command line run flutter packages pub run build_runner build

Again, I get 0 output when doing this.

[eernstg]

Maybe it's because you're not specifying what to build: flutter packages pub run build_runner build other. (Perhaps test is being built by default, but build_runner has no default settings for other or anything else that it hasn't heard about.)

[CryptUser]

I tried flutter packages pub run build_runner build other and flutter packages pub run build_runner build other/main.dart as well, with the same result. Does it work for you?

[eernstg]

Does it work for you?

Trying it now.

Also, we have this sentence here:

generate_for: List of String or Map, Optional:. The subset of files within
the target's sources which should have this Builder applied.

which seems to confirm that 'generate_for' is about filtering something which has already been selected as a target, not about getting a target in the first place.

[eernstg]

(.. there is no web/main.dart in https://github.com/dart-lang/reflectable, and there isn't even a web directory ..)
(Ah, it's from the README text; got it)

[CryptUser]

I mean the one inside the readme text (scroll down the page), under the headline Usage.

[eernstg]

I get the same behavior: Build will not generate code for anything in other, but it does happen for entry points in test and example. It seems like there are some directories which are on a positive list, and all others are ignored. Maybe it's just something I should have seen in a config file, but I hope @jakemac53 will clarify this.

[eernstg]

By the way, here's the "not in lib" rule: https://www.dartlang.org/tools/pub/package-layout#public-libraries. And here's the whitelist: https://www.dartlang.org/tools/pub/glossary#entrypoint-directory, so you could try to see if it works for you to stick to one of those.

Apart from that I'm sure that there will be more conflicts than this one concerned with the treatment of lib by Flutter (here's the rule: https://flutter.io/flutter-for-react-native/#project-structure-and-resources, that the Flutter entry point is lib/main.dart, period).

[CryptUser]

Thanks for these links, they helped a lot. While the first one says

Entrypoints—Dart scripts with a main() function—cannot go in lib.

the third one says

In Flutter, the entry point file is ’projectname’/lib/main.dart

No wonder is the lib folder somewhat special for Reflactable with Flutter. Thanks to your second link I could figure out that putting main.dart in the 'bin' folder works - even without the build.yaml file. In the lib folder I did not get it to work without the build.yaml file, but with it even the lib folder produced the main.reflectable.dart file. With that, I think I should get Reflectable to work in a real project. Thanks for your time!

[eernstg]

Cool, thank you!

[nareshdb]

In my case, I was always getting The Flutter SDK is not available with 'pub run '
When I followed @zoechi 's suggestion flutter packages pub run <bla bla>, I got no output for a long time so I killed the process.
Then without doing anything else, I ran pub run <bla bla> and it worked. 😆 🙌

[JPinkstonSaatva]

@nareshdb What test library do you have in your dev_dependencies? In order for flutter pub run <bla bla> to work, you need to be using flutter_test. If pub run <bla bla> is working you are most likely using test and not flutter_test. Hope this helps.

[Bozayi]

Your project is probably showing on your global dart installation, not on [path-your-flutter-SDK]/flutter/bin/dart. Check your flutter dart path.
$ which flutter dart
if it's looking like this,

  [/path-to-flutter-sdk]/bin/flutter
  /usr/local/bin/dart

make sure that your flutter and dart SDK show on the same path like this.

[/path-to-flutter-sdk]/bin/flutter
 [/path-to-flutter-sdk]/bin/dart

[github-actions]

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