dart run build_runner build cn't running properly

[anandsathya80]

when running dart run build_runner build --delete-conflicting-outputs get message :

[INFO] Generating build script completed, took 258ms
[WARNING] Throwing away cached asset graph due to version mismatch or corrupted asset graph.

You have hit a bug in build_runner
Please file an issue with reproduction steps at https://github.com/dart-lang/build/issues

PathNotFoundException: Deletion failed, path = '.dart_tool/build/generated' (OS Error: The system cannot find the path specified.
, errno = 3)
dart:async _CustomZone.runUnary
package:build_runner_core/src/generate/build_definition.dart 333:7 _Loader._deleteGeneratedDir
dart:async Future.wait.
package:build_runner_core/src/generate/build_definition.dart 411:9 _Loader._tryReadCachedAssetGraph.
package:build_runner_core/src/logging/logging.dart 25:18 logTimedAsync
package:build_runner_core/src/generate/build_definition.dart 213:22 _Loader.prepareWorkspace
package:build_runner_core/src/generate/build_impl.dart 114:27 BuildImpl.create
package:build_runner_core/src/generate/build_runner.dart 34:26 BuildRunner.create
package:build_runner/src/generate/build.dart 109:17 build
package:build_runner/src/entrypoint/build.dart 35:18 BuildCommand._run
package:args/command_runner.dart 212:13 CommandRunner.runCommand
package:build_runner/src/entrypoint/run.dart 26:18 run
.dart_tool\build\entrypoint\build.dart 82:16 main

[jakemac53]

Interesting, was this a one-off error or is it continuing to happen? Is it possible you had multiple build_runner instances going at the same time, or some other task which might have deleted your .dart_tool dir while running a build?