Bad state: Failed to find package_config.json on Flutter's master channel

[rrousselGit]

Context: I'm trying to use build_runner on Freezed using Flutter's master channel.
But I get the following exception:

remirousselet@mac freezed % dart run build_runner watch -d            
Unhandled exception:
Bad state: Failed to find package_config.json.
#0      BuildPackagesLoader.forPaths (package:build_runner/src/build_plan/build_packages_loader.dart:36:7)
#1      BuildPackages.forPaths (package:build_runner/src/build_plan/build_packages.dart:178:32)
#2      loadBuilderFactories (package:build_runner/src/bootstrap/build_script_generate.dart:71:45)
#3      generateBuildScript (package:build_runner/src/bootstrap/build_script_generate.dart:23:34)
#4      Bootstrapper._writeBuildScript (package:build_runner/src/bootstrap/bootstrapper.dart:171:31)
#5      Bootstrapper.run (package:build_runner/src/bootstrap/bootstrapper.dart:69:13)
#6      BuildRunner._runWithBuilders (package:build_runner/src/build_runner.dart:218:31)
#7      BuildRunner._runOrThrow (package:build_runner/src/build_runner.dart:109:20)
<asynchronous suspension>
#8      BuildRunner.run (package:build_runner/src/build_runner.dart:51:14)
<asynchronous suspension>
#9      main (file:///Users/remirousselet/.pub-cache/hosted/pub.dev/build_runner-2.14.0/bin/build_runner.dart:11:7)
<asynchronous suspension>

Freezed is not using workspaces.

pwd is:
<path/to/freezed>/packages/freezed

There's a packages/freezed/.dart_tool/package_config.json (but no <root>/.dart_tool/package_config.json). My guess is that build_runner is incorrectly trying to obtain the package_config from the root

Note

build_runner appears to be creating a .dart_tool at the root of the git repository. I don't have any pubspec at the root of the project, so there's no reason for build_runner to create one there.
Specifically, it is creating a <root>/.dart_tool/build/lock/build_runner.workspace.lock

This could be related to the fact that I have an analysis_options.yaml at the root of the project, but no associated pubspec.yaml

[rrousselGit]

I've worked around the issue by temporarily using workspaces in Freezed.

[davidmorgan]

Thanks for reporting! I think I see the issue.

build_runner will think you are using workspaces if it finds packages/freezed/.dart_tool/pub/workspace_ref.json.

But this file is not cleaned up if you stop using workspaces.

So it looks like you did try workspaces at one point, and the workspace_ref.json was left lying around and now confuses build_runner. You should be able to get it working as you want by deleting that file.

I will fix by making it always check for resolution: workspace before concluding there is a workspace.